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Message from db1 at Thursday, 06-Jan-11 16:05:05 GMT
Hi everyone. I am not writing this to show off or anything like that, but thought some people might like to hear of some results concerning a EWE antenna I have made. I have been asked about HF (shortwave) antennas a few times recently by new users on Globaltuners and I thought maybe if I wrote something in the forum section it might allow more new users to have a read and a think about how they might be able to start receiving some things at their own home. For new users, a longwire antenna is a quick and often very effective way of getting an antenna up and hearing stations, but if you want to try something else, then a EWE antenna might interest you.
First of all, if you are new to antennas and radios, don't be put off by mentions of things like longwires/ beverages, verticals etc. They are just types of antennas that people often use. Also, don't be put off by any other "technical" words.
This post also isn't saying "EWEs are best...etc.", as everyone has their own opinions on antennas and some people have had more experience with a wider range of antennas, and know more technical information than myself. Also, different antennas are better in different circumstances and not as good in other circumstances. I've only really made longwires, longwire/beverages, low dipoles and the EWE. I once tried a 1/4 wave vertical but had absolutely no luck with it at all. This is not saying anything against this antenna, but just that it wasn't working with what I wanted (a broadband antenna {see further below for explanation} able to not take up much height or space) and I probably was not making it as best as it could have been made either.
Anyway, seeing as the EWE antenna is (or was) a very popular antenna with Globaltuners (and formerly Javaradio, Javoradio, Dxtuners) operators, but not really widely known about, I thought some people might want to try them out as well at their own location, and so some information of my results might be of interest to such people. In the following I have used some quite long sentences and added brackets in parts to give some little explanations of words and concepts).
Background:
I don't have much room for antennas at my house, so its either low longwires / bent beverages or something small.
I had once before made a EWE antenna but I had to take it down when we cut down a supporting tree. Since then its only been low wires (one of these is a kind of longwire beverage i.e. a very low wire around my house's fences.)
I don't want to put up huge antennas that will block my neighbours' views, so any antenna has to be quite low. Antennas can be great for radio users but we also need to be considerate to our neighbours who have to live with the antenna being there too.
I decided on the EWE from having had fantastic results from Kelly Lindman's radio on Javaradio/Dxtuners (Kelly used to run the website before it became GlobalTuners), where he had 7 or 8 EWES facing different directions of the globe, that you could switch between, to find out where a signal was coming from and to get the best signal.
The EWE is a dream antenna for those with not much space, and from my experience (I stress its only my opinion based on my use of antennas - please don't be offended anyone who has had more experience and does not agree), in terms of a "broadband" antenna (i.e. made for covering a wide area of the HF {shortwave} bands, as opposed to being built just for one or a small number of particular frequency areas), the EWE can match the reception of big antennas up high in the air, and receive signals better than them sometimes too, because of the fact that they put a wire to the ground (this is called "terminated" i.e. a wire goes from the antenna to the earth) therefore cutting out static which can build up on high un-terminated ended antennas, and also because they are directional and broadband in nature.
As I said, I am NOT an expert when it comes to high up receiving antennas and so I am sure such antennas can be made to be "the best!", and better than any smaller antenna (like the EWE) and that it is due to noisy environments, or the fact that they are usually made for only certain frequency areas, and other factors that sometimes might make them sound noisy compared to the EWE on various frequency areas ( note: some people also get terrible results with a EWE - because of things like different soils etc. but different resistor values and different techniques can probably get around these problems).
Also, high up and "big" antennas are going to give you MORE GAIN - (i.e. more strength in the received radio signal), than a EWE antenna, and a high, big antenna can be brilliant for people who are interested in certain set frequency areas, and in these cases, broadband is not what is desired. The good thing about the EWE though, is that it gives a great forward to back ratio in reception,( i.e. noise or other stations coming from behind the antenna can be blocked out, and so the station in front becomes hearable.) The lost gain (compared to some bigger antennas) can be bumped up by using a preamplifier ( which although boosting the noise level too, still has that great forward to back ratio to work with, and so the wanted signal is hopefully :) stronger than the backwards interference.
Of course, not all interference is going to come from behind the antenna, and so a higher, bigger antenna may receive the signal more than the noise (due to different angles of the radio waves (i.e. the noise might be coming from a high angle from above, and the wanted signal from a lower angle, and a high vertical antenna (straight up and down) might get the wanted lower signal better than it gets the high up noise? This would need someone else to say if this is correct - I honestly am not the best person to say this is correct or not).
Back to the pre-amp. I am not using a preamplifier myself but might eventually get around to making one and test how it goes with one.
Anyway, I decided a while back that I was going to start again and build 4 EWEs. They were to be roughly North South East and West independently. I have since decided that it is going to be less effective to have a north and south EWE, as it would mean making one antenna smaller and also it would mean pointing them more to the north north east (NNE) and south south west(SSW). Instead I am choosing to have an antenna that I can operate by a switch ( or switches) and make it north or south and 2 other antennas for east and west ( in reality these will be east south east(ESE) and west north west(WNW). The switching part will be done in the future, when I can get round to it and work out the best way of doing it.
What is the EWE and how does it work?
A Ewe antenna is an HF and broadcast band, broadband, directional antenna (mainly made for lower hf frequencies up to 10/11mhz or so, although fine for higher frequencies too but with less gain {signal strength} and without the directionality), designed by a man called Floyd Koontz, that can be built with various possible dimensions but most often it is 7.5 metres (25 feet) of wire strung between 2 vertical wires/or metal poles of 3 metres (10 feet) height (or simply one wire with bends to make one part horizontal and the other two parts vertical).
The horizontal wire is basically just joining the two vertical poles/wires, which are responsible for most of the effectiveness of this antenna. The 2 verticals being in line with each other (i.e. one behind the other - in line with the general direction you want to receive), and being "fed" at the coaxial cable end at the bottom and fed at the top at the rear pole ( for information on this "feeding" see the dxing.info webpage below- I am probably not describing it very well), causes directionality to occur towards the front of the antenna where the coaxial cable is connected (i.e. the antenna receives signals from one direction more than it receives from other directions - this helps you hear something in one direction without as much interference from things coming from other directions.). Furthermore, the back end is sent down into the ground (terminated) through a resistor ( I use a variable resistor - see further below for explanations) and this further increases directionality. It actually can "block out" a signal from a station that is coming from behind it. This means that if for instance you are listening for a station in the north and a station in the south is interfering, you can adjust the resistor until
(hopefully) the southern station is removed entirely (or made weaker).
Here is a video someone has made which shows this happening. It starts with one EWE and then switches to another EWE facing the other way...you will notice the change in station on the same frequency.
http://www.youtube.com/watch?v=8pbONcJXW3U&feature=related
How I constructed the antenna:
(See further down for pictures showing the parts mentioned)
I already had the vertical parts, as I had planned on doing this a few years ago but never got around to it. They are thin (aluminium tubes (3 metres long). You can easily use wire for the entire antenna but you will need something to support each end of the horizontal part, like two trees or other non- metallic posts (metallic posts could probably be used as long as they are very very close to the vertical wires but I am not sure that they wouldn't affect the effectiveness of the antenna, so I tried to avoid this option myself. The designer of this antenna however has 4 seperate EWEs with the front ends of each only seperated by a post width, so it obviously can be done. Large metal objects though are best not to be near the antenna if you can avoid it and (according to the websites below) best not to be within about 10 feet of the front of the coax end of the antenna.
I also have an "un-un" (not a balun) that matches up the antenna's impedence (somewhere round 450 ohm) to the coaxial cable I use (50 ohm). Don't worry about words like "un-un" or balun. All that you need to
know is that they are little things you can either make or buy, that will go "in between" the antenna and the coaxial cable that goes eventually to the 50 ohm input (or a 75 ohm input) of your radio.
Basically the cable is "different" from the antenna electrically and so they need to "match up" to each other as best they can to produce the best signal to the radio. You will find explanations on the websites below. For anyone who remembers, often tvs would have a balun where the cable from the tv antenna would connect to the back of the tv. These are different ones but thats what a balun is. This however is an un-un, but it is a similar kind of thing. (a balun means "balanced to balanced" whereas an un-un means "unbalanced to unbalanced".
The coaxial cable I am using is called 50 Ohm RG-58C/U. You can get this at an electronics store. It might have a slightly different name but just make sure its 50 ohm and called something like rg-58. You could use other 50 ohm coaxial cables (made for hf) but they are much more expensive. They are better than the rg-58, as they don't lose as much signal, but if you need a fair bit in length, I personally choose the cheaper. It is normally suggested that people choose the better one if they need it quite long (over 30 metres?), to avoid losing as much signal strength, but even then, I personally would choose the cheaper one....but thats just my preference. Feel free to choose what you would prefer.
You will also need some plugs to connect the coaxial cable to the un-un and to the radio. The plugs you need depends on what your radio and un-un use. I use a pl-259 (also called a uhf connector - even though we are using it for hf and not UHF....don't worry....its just the name :) ) as this fits my hf receiver, and a BNC connector for connecting to the un-un.
For the 7.5 metre horizontal part of the antenna, I used plastic coated, hard but bendable wire (from a hardware store). Again, others might prefer copper wire or stranded wire etc. but this is what I am using just now, and one day I might try something else.
I stripped back some of the plastic coating to leave maybe 4 centimetres of bare wire exposed on each end. I then put some hose clamps (used for clamping garden hoses) on the ends of the aluminium poles. I then placed the exposed ends of the wire between the clamps and the poles and tightened the clamps. ( I will put tape over these areas eventually to weatherproof them too).
At the bottom I connected a small wire (same type of wire - but doesn't have to be) to the bottom of the "front" (north) pole and connected it to the "antenna" wingnut of the un-un. (This is just one side of the un-un and it is where the antenna goes. The other part of the un-un is to take a wire from it to the ground.
I connected a wire from the "ground" wingnut of the un-un, to a ground rod ( a metal pole I put into the ground - I used copper, but only because there was some in the house when we came to live here - it can be a bit expensive if you have to buy it though - although depending on who you talk to, copper is normally seen as the best for lightening protection... please read up on safety when it comes to proper ground rods, i.e. what to use and how to go about putting them into the ground. Please don't just use whatever you have until you have asked an expert. I use some galvanised steel for other ground rods (I haven't tried them with a EWE though) but these are for low antennas. I honestly don't know if they are good to use or not as there is no copper coating on them at all and usually copper is advised. Maybe someone else can write a post on what you can use for ground rods (and their length). I think my ground rods are around 3 feet long each. Normally people use 8foot long ground rods for grounding antennas,
but for this antenna I used the copper I had and it works great (for reception - for lightening protection it might be another story). It is normally adviseed to also put another ground rod below the place where your coaxial cable will eventually enter your building. You might want to make this one longer and use this one more for protection, although really every rod should be used also for protection.
The coax plugs into the unun and leads back to my radio.
At the other end, a clamp at the bottom of the rear (south) pole clamps a wire that goes to one connector on a variable resistor (potentiometer) ( You can get these at Electronics stores) (I am using a 1kohm variable resistor - If you have harder soil or dry conditions, you might want a 2kohm variable resistor). Again, you don't need to know about resistors etc., just to know that a variable resistor is easier to use than a normal resistor because you can adjust it to find the best "resistance value". Another wire goes from another connector of the variable resistor, to a clamp on another ground rod in the ground.
One thing that concerned me was that about 4 metres away from the front of the antenna, is a concrete wall of a couple of metres height and a small metal fence above that. Behind the concrete is earth, as the house next door is up higher than our house. I don't know what effect this is having on reception and whether it makes reception of "lower angled" signals, less likely than higher angled signals, but I put the antenna as far away from it as I thought was the most I could due to the fact that most of the area below the 7.5m wire, is concrete, and I didn't want the pole to be over concrete.I have wondered whether the concrete below will affect the performance , and I briefly tried a kind of "couterpoise" (this is simply connecting a wire to the ground connections at both ends of the antenna and having this wire run below the 75m wire and on top of the concrete), but I decided it wasn't necessary, as I was still getting good results the next day without it. I might still look into this and test a counterpoise again, and then decide how best to place it if I decide to have one. I don't really want a wire running along the concrete where it might trip someone up, and look a bit ugly too.
Test results.
After I set everything up I did some testing.
I haven't done much testing so far with the resistor value but I looked up broadcast band frequencies that are from stations to the south west of me ( in fact its closer to west south west), and one so happened to be the same frequency as I was hearing a station in the North (although possibly from a relay). This was 720khz. I should say though, that I think the northern station was actually an "accidental" broadcast ( these are like fainter images of the proper broadcast on another frequency that are accidentally broadcast in other parts of the radio band).
I tuned it on the radio and heard the cutting in/out sound of both stations. It was hard to make out things being said because they both were interfering with each other. I turned the radio's volume up, so that I could hear it where I have the antenna and I walked over to the back end of the EWE and slowly turned the knob of the variable resistor. As I did it, the west-south-west station reduced in strength and then disappeared totally, and the northern station was clear and strong. The fact that the unwanted signal was coming from the west south west instead of from direct south, shows either the strength of the Koontz design at reducing rear signals- even from west south west etc., or it is possible that other nearby objects in my backyard are affecting the directionality as well. In any case, it is interesting that the signal from west south west could be entirely blocked by turning the variable resistor. The page at http://www.ok1rr.com/e107_plugins/content/content.php?content.114 shows what is called an Azimuth pattern. This in a way shows the EWE's strength of reception from different directions. As you can see, most of the part behind 90 and 170 degrees, is weaker than the signal from above. It will take me some time to find the best point on the resistor for HF (shortwave), but I will spend some time soon trying to find that.
Unfortunately my longwire antenna is fed (i.e. connected to some coaxial cable) through to a room upstairs and so I couldn't quickly compare results or directions of signals, but I suddenly noticed that with the EWE, I was now receiving lots of Japanese signals...much more than I usually receive. ( I personally listen more to what are called Utility stations, and these are often weaker than broadcast stations.)
I am in New Zealand, so Asia is to the north (or north west). I was hearing a lot of utility stations I had never heard before, and while I was still picking up stations from the other side of the world, I think these were taking the path from the North to get to me. Russian frequencies were coming in nicely too (again - these were not hearable on the longwire/beverage at all). Comparing it to the other antenna, it wasn't just due to noise that I wasn't picking them up. I couldn't even hear the stations transmitting, on the long./bev but the EWE was giving me a strong signal with no (or little) noise. It is possible that some of these stations might have become hearable if the longwire bev was higher in the air for more of its' length, or pointed in a different direction, but I will eventually reverse the connections on the EWE and let you know if the south suddenly becomes hearable instead of the north.
I was mainly tuning around 6 mhz, 8mhz and 9mhz but around 2,3 and 4 mhz, it was noisier and I didn'thear much (in terms of utility stations). This was mainly due to the fact that I only tried for a few minutes, as I have less interest in these areas (not that they are less interesting, but just that I spend less time bothering tuning there). It was probably/possibly that there was nothing transmitting when I was tuning. The noise may also have been noticed because I had had such good reception around 5-10 mhz etc. that I naturally felt disappointed when I briefly tried 2,3,4 mhz. Also, these areas are known to be noisy compared to higher areas, and that is why the EWE was made with these areas in mind. I personally don't have a lot of experience tuning 2 and 3 mhz, but I know it is harder to pick up signals in these areas due to the higher noise levels.
At the moment it is raining here and I am not getting the chance to dig little holes to pour some concrete in to support the antenna. I am going to put pvc pipes into the concrete to act as sleeves for the antenna poles. I am going to put other pvc pipes over the bottom parts of the poles and these will slot into the sleeves. I am also going to put some wooden poles inside them too and connect some ropes to act as guy ropes to further support the poles. These ropes will be pegged into the ground. This will allow me to take the antenna down at any point and keep the backyard relatively "normal" looking when its not needed ( although I am sure I will probably be wanting the antenna up most of the time :) ). With this method though I should be able to take it down before any strong winds are forecast...just in case.
I have added the next bit ( done a few days later) to this post so that all of the results and pictures are together. The rest of it can be seen in the later post.
Ok, today I have put the EWE up again, but this time I have faced it southwards, pointing in between South America and Africa (if you picture going "from" New Zealand, down through the Antarctic, and up the other side of the globe).
Here are some pictures of the bits and pieces I am using:
These are the alluminium poles:
http://img573.imageshack.us/i/dscf3582g.jpg/
Here they are again with the 7.5 metre wire attached by the hose clamps:
http://img31.imageshack.us/i/dscf3579t.jpg/
The next picture shows the bottoms of both poles, with the hose clamps on and with the wire that will go to the antenna wingnut of the un-un (I have this wire on already because the pole is going into the box of wood and it would be impossible to put it on once its in:
http://img691.imageshack.us/i/dscf3580a.jpg/
Here is the back end, in position, balanced/held up by wood and a wooden chair:
http://img340.imageshack.us/i/dscf3583h.jpg/
This shows the bottom of the rear pole, with a wire from it going to the variable resistor (or called potentiometer), and a wire from another connector of the variable resistor going to the hose clamp on the ground rod:
http://img337.imageshack.us/i/dscf3584o.jpg/
Note in the picture above I have two wires going to the rod. This is not required. I had to do this originally to allow me to have one wire to the ground rod and the other connected to another wire that ran along the ground (directly underneath the horizontal 7.5 metres wire) and joined up to the ground rod at the other pole. This wire was 7.5 metres too. This is the counterpoise I mentioned that I tried just in case the concrete was affecting things. I don't know if a counterpoise (if used) has to go straight to the other end or if it can go off at an angle and then come back to the other ground rod. I had originally thought I would need one because the original idea meant that one vertical would be coming down to concrete-not soil, so I thought I would need it, but I have since changed the plan and now both ends are above soil.
This next picture shows the wire from the Variable Resistor fastened to the ground rod by the hose clamp (the ground rod clamps are bigger than the others due to the rod being wider than the antenna poles.)
http://img402.imageshack.us/i/dscf3587c.jpg/
Here is a close up of the Variable resistor. The middle one doesn't have to go through that little hole by the way. I just did it that way. Also, it doesn't have to be soldered in this order. I was thinking afterwards I wanted to put the antenna wire on one of the end connectors of the variable resistor, but I had already done it this way and I looked it up to make sure this was ok and it supposedly is, so thats ok. It just depends what way you want to turn the variable resistor, to get higher blocking of signals coming from directions behind the rear of the antenna.
http://img600.imageshack.us/i/dscf3588v.jpg/
This shows the bottom of the rear pole:
http://img98.imageshack.us/i/dscf3589.jpg/
This is the "front end" of the antenna. The front pole goes into the box at the top of the picture, and a wire that is clamped to the bottom of this pole, pokes out of that little hole at the bottom (on the side) of the box. This wire then connects to the antenna wignut of the un-un, which is pictured on the piece of wood (with the coaxial cable connected, running back to the radio - which is stuck in between bushes :) )
http://img602.imageshack.us/i/dscf3590.jpg/
This shows the same:
http://img233.imageshack.us/i/dscf3591r.jpg/
Here is the rear pole after the front end has been put up too :
http://img714.imageshack.us/i/dscf3595s.jpg/
This is taken from behind the rear pole, showing the front pole (hard to see) in the distance. This also shows the direction it is pointing. You can see the water in the distance. Thats the Pacific Ocean, and after that its Antarctica and then between South America and South Africa.
http://img255.imageshack.us/i/dscf3596.jpg/
This shows the front pole in the box of wood:
http://img220.imageshack.us/i/dscf3598e.jpg/
This shows the front pole (side on), and where the radio had to be to test it - the coax cable was only long enough for there, so I had to sit half in between some bushes - some of which was Blackberry with thorns :(
http://img59.imageshack.us/i/dscf3608.jpg/
This shows it side on after it was all up:
http://img508.imageshack.us/i/dscf3612.jpg/
This is just before I pulled it down again. It was getting dark and a bit cold, so I decided to stop:
http://img521.imageshack.us/i/dscf3613d.jpg/
Todays results:
A funny story first. I had everything set and I turned on the receiver (which wouldn't go at first...a thing that can happen with frg-8800s when unplugged, and so I had to take a battery [used for keeping the memory of frequencies] out (which resets things), and tried the AM broadcast band. I thought "I wonder if this will now block out the bigger radio stations (that come from the North Island of NZ) and be stronger on the ones down south west?"
I turned the radio's tuning knob and there was hardly anything showing up. Even the big stations were weak and had noise.
I was excited, and thought "Wow, this antenna blocks rear signals better than I thought it could".
While I was pleased, it just didn't feel right...so I looked around and checked everything.....and all seemed fine....so I dis-connected the coaxial cable and there was no change in sound. I thought I must have damaged my radio when I accidentally pulled the power cord and pulled the radio a bit off of the little step ladder it was on. Then I looked, and saw that I had had the cable plugged into the wrong socket :)
The radio also has a socket for an antenna to listen to the vhf airband and I had plugged the ewe into that by mistake. The radio was in the garden and so I had had to plug the cable in while standing in front of it (i.e. instead of being behind the radio and plugging it in with the socket visibly in front of me).
I quickly changed it and the broadcast band was back to normal.
It did however still weaken rear signals like the other day, but now in reverse i.e. blocking north stations because I had now pointed the antenna south instead of north. Of course the northern stations were still there ( seeing as they are from New Zealand), and also because I think they are all rebroadcast anyway from a mountain in Dunedin where I live, so there wasn't really any way of blocking them :) ....even by plugging into the wrong socket.
Anyway, I had a quick tune around but it was afternoon, so no real chance of hearing any other countries' AM broadcast band stations. I tried later when it got darker, but not for long, but didn't hear anything really. There were a couple of things I wasn't sure about but they were probably NZ stations.
I'm not really an AM (called broadcast or MW band) person anyway (although when I get the ewe up properly I think I will enjoy trying it at night for other countries' normal local AM stations.
HF (shortwave)
I was really wanting to try hf, so I tuned around in the afternoon and I was getting loads of Spanish speaking shortwave broadcast stations. It was very sunny here (for any new radio people - the sun's position in the sky affects which radio waves get to you and which ones don't, from other countries)(I can't be sure of the time- I just know I was getting hot) and yet I was getting some great signals. I was even getting them around 6 mhz (and lower? ..I can't remember) ( normally during daytime, transmissions from overseas are on higher frequencies, and when night they go to lower frequencies). I don't listen a lot to shortwave broadcast stations, so I cannot say for sure if the antenna was responsible or not, but it seemed so much of a coincidence that most were Spanishy sounding and no ( or nearly no) strong noticable Asian stations (i.e. as I tuned, nothing jumped out strongly that was Asian..) Maybe I was telling myself that everything was Spanishy but I also got something that sounded possibly from the Caribbean, and some Middle Eastern/African sounding etc. I also possibly hearing European things too I think. It wasn't so much what I heard ( although that was convincing me that the antenna was really working superbly), but what I "didn't" hear. I wasn't noticing Asian stations.
When I tried tuning for utility stations ( aircraft etc. ) and amateur radio areas, again, I only heard Asian things a few times. The other day, nearly everything seemed Japanese. I came across various Atlantic civil aviation frequencies like Santa Maria and Gander. I didn't hear any Asian aviation freqs, although strangely I did have San Francisco coming in ok. I don't know what path the San Fransisco signal was taking to reach me. It could have come to the front of the antenna, but it might have simply been from the back. I suppose I shouldn't expect the antenna to be blocking out everything from behind it. I never used to expect that. Its just since the other day and the seemingly fantastic directionality I was getting, you then start to expect no rear signals at all :) (Well, not really expecting that, but you get a bit disappointed when you hear something from behind.)
Variable Resistor:
Throughout today, I went back and forth, adjusting the variable resistor value ( how much the knob is turned ), to see what would happen. Sometimes, not a lot happened, probably because the noise was from the same direction as the wanted signal.
Some stations however, you really noticed funny things happening.
I heard a utility station which sounded Spanishy, but I found that the signal strength increased when I turned the knob the "other" way (i.e. the way to have not so much blocking of rear signals).
I think the station might actually have been from the Phillipines or somewhee else in Asia, and thats why it was Spanish.
I know for certain though, after today's and the other day's testing, that the variable resistor really does work and really does weaken rear noise and signals/ and increase the signal from in front.
Hopefully this hasn't been too long, and has been helpful to someone. I'll try and answer any questions anyone has, and maybe some others who use EWEs will give some insights into how they get theirs to be the best they can get them to receive.
Can I ask a favour of people replying to this post? :)
Just to keep the forum posts tidy for people wanting to read only about the EWE antenna, could people who want to give their opinions on other types of antennas, please start seperate threads for each type of antenna design? I am sure people would love to read the views of people who know a lot about other designs and how they compare with or are better than the EWE, but just to keep things tidy, it would be great if this thread could just be about the EWE.
Thanks for that in advance. :)
The main sources of info which my explanations are based on for the workings of the ewe, are the following:
http://www.dxing.info/equipment/ewe.dx
http://www.ok1rr.com/e107_plugins/content/content.php?content.114
and for a switching version between 4 or more EWE's:
http://www.ok1rr.com/e107_plugins/content/content.php?content.115
Other understandings were gained from various sources over time like Marc Robinson (VK2BUA), in an article in Amateur Radio magazine, reprinted in Break In magazine, concerning static and terminations.
Last edited by db1 at Sunday, 09-Jan-11 12:28:26 UTC
Last edited by db1 at Monday, 10-Jan-11 12:20:42 UTC
First of all, if you are new to antennas and radios, don't be put off by mentions of things like longwires/ beverages, verticals etc. They are just types of antennas that people often use. Also, don't be put off by any other "technical" words.
This post also isn't saying "EWEs are best...etc.", as everyone has their own opinions on antennas and some people have had more experience with a wider range of antennas, and know more technical information than myself. Also, different antennas are better in different circumstances and not as good in other circumstances. I've only really made longwires, longwire/beverages, low dipoles and the EWE. I once tried a 1/4 wave vertical but had absolutely no luck with it at all. This is not saying anything against this antenna, but just that it wasn't working with what I wanted (a broadband antenna {see further below for explanation} able to not take up much height or space) and I probably was not making it as best as it could have been made either.
Anyway, seeing as the EWE antenna is (or was) a very popular antenna with Globaltuners (and formerly Javaradio, Javoradio, Dxtuners) operators, but not really widely known about, I thought some people might want to try them out as well at their own location, and so some information of my results might be of interest to such people. In the following I have used some quite long sentences and added brackets in parts to give some little explanations of words and concepts).
Background:
I don't have much room for antennas at my house, so its either low longwires / bent beverages or something small.
I had once before made a EWE antenna but I had to take it down when we cut down a supporting tree. Since then its only been low wires (one of these is a kind of longwire beverage i.e. a very low wire around my house's fences.)
I don't want to put up huge antennas that will block my neighbours' views, so any antenna has to be quite low. Antennas can be great for radio users but we also need to be considerate to our neighbours who have to live with the antenna being there too.
I decided on the EWE from having had fantastic results from Kelly Lindman's radio on Javaradio/Dxtuners (Kelly used to run the website before it became GlobalTuners), where he had 7 or 8 EWES facing different directions of the globe, that you could switch between, to find out where a signal was coming from and to get the best signal.
The EWE is a dream antenna for those with not much space, and from my experience (I stress its only my opinion based on my use of antennas - please don't be offended anyone who has had more experience and does not agree), in terms of a "broadband" antenna (i.e. made for covering a wide area of the HF {shortwave} bands, as opposed to being built just for one or a small number of particular frequency areas), the EWE can match the reception of big antennas up high in the air, and receive signals better than them sometimes too, because of the fact that they put a wire to the ground (this is called "terminated" i.e. a wire goes from the antenna to the earth) therefore cutting out static which can build up on high un-terminated ended antennas, and also because they are directional and broadband in nature.
As I said, I am NOT an expert when it comes to high up receiving antennas and so I am sure such antennas can be made to be "the best!", and better than any smaller antenna (like the EWE) and that it is due to noisy environments, or the fact that they are usually made for only certain frequency areas, and other factors that sometimes might make them sound noisy compared to the EWE on various frequency areas ( note: some people also get terrible results with a EWE - because of things like different soils etc. but different resistor values and different techniques can probably get around these problems).
Also, high up and "big" antennas are going to give you MORE GAIN - (i.e. more strength in the received radio signal), than a EWE antenna, and a high, big antenna can be brilliant for people who are interested in certain set frequency areas, and in these cases, broadband is not what is desired. The good thing about the EWE though, is that it gives a great forward to back ratio in reception,( i.e. noise or other stations coming from behind the antenna can be blocked out, and so the station in front becomes hearable.) The lost gain (compared to some bigger antennas) can be bumped up by using a preamplifier ( which although boosting the noise level too, still has that great forward to back ratio to work with, and so the wanted signal is hopefully :) stronger than the backwards interference.
Of course, not all interference is going to come from behind the antenna, and so a higher, bigger antenna may receive the signal more than the noise (due to different angles of the radio waves (i.e. the noise might be coming from a high angle from above, and the wanted signal from a lower angle, and a high vertical antenna (straight up and down) might get the wanted lower signal better than it gets the high up noise? This would need someone else to say if this is correct - I honestly am not the best person to say this is correct or not).
Back to the pre-amp. I am not using a preamplifier myself but might eventually get around to making one and test how it goes with one.
Anyway, I decided a while back that I was going to start again and build 4 EWEs. They were to be roughly North South East and West independently. I have since decided that it is going to be less effective to have a north and south EWE, as it would mean making one antenna smaller and also it would mean pointing them more to the north north east (NNE) and south south west(SSW). Instead I am choosing to have an antenna that I can operate by a switch ( or switches) and make it north or south and 2 other antennas for east and west ( in reality these will be east south east(ESE) and west north west(WNW). The switching part will be done in the future, when I can get round to it and work out the best way of doing it.
What is the EWE and how does it work?
A Ewe antenna is an HF and broadcast band, broadband, directional antenna (mainly made for lower hf frequencies up to 10/11mhz or so, although fine for higher frequencies too but with less gain {signal strength} and without the directionality), designed by a man called Floyd Koontz, that can be built with various possible dimensions but most often it is 7.5 metres (25 feet) of wire strung between 2 vertical wires/or metal poles of 3 metres (10 feet) height (or simply one wire with bends to make one part horizontal and the other two parts vertical).
The horizontal wire is basically just joining the two vertical poles/wires, which are responsible for most of the effectiveness of this antenna. The 2 verticals being in line with each other (i.e. one behind the other - in line with the general direction you want to receive), and being "fed" at the coaxial cable end at the bottom and fed at the top at the rear pole ( for information on this "feeding" see the dxing.info webpage below- I am probably not describing it very well), causes directionality to occur towards the front of the antenna where the coaxial cable is connected (i.e. the antenna receives signals from one direction more than it receives from other directions - this helps you hear something in one direction without as much interference from things coming from other directions.). Furthermore, the back end is sent down into the ground (terminated) through a resistor ( I use a variable resistor - see further below for explanations) and this further increases directionality. It actually can "block out" a signal from a station that is coming from behind it. This means that if for instance you are listening for a station in the north and a station in the south is interfering, you can adjust the resistor until
(hopefully) the southern station is removed entirely (or made weaker).
Here is a video someone has made which shows this happening. It starts with one EWE and then switches to another EWE facing the other way...you will notice the change in station on the same frequency.
http://www.youtube.com/watch?v=8pbONcJXW3U&feature=related
How I constructed the antenna:
(See further down for pictures showing the parts mentioned)
I already had the vertical parts, as I had planned on doing this a few years ago but never got around to it. They are thin (aluminium tubes (3 metres long). You can easily use wire for the entire antenna but you will need something to support each end of the horizontal part, like two trees or other non- metallic posts (metallic posts could probably be used as long as they are very very close to the vertical wires but I am not sure that they wouldn't affect the effectiveness of the antenna, so I tried to avoid this option myself. The designer of this antenna however has 4 seperate EWEs with the front ends of each only seperated by a post width, so it obviously can be done. Large metal objects though are best not to be near the antenna if you can avoid it and (according to the websites below) best not to be within about 10 feet of the front of the coax end of the antenna.
I also have an "un-un" (not a balun) that matches up the antenna's impedence (somewhere round 450 ohm) to the coaxial cable I use (50 ohm). Don't worry about words like "un-un" or balun. All that you need to
know is that they are little things you can either make or buy, that will go "in between" the antenna and the coaxial cable that goes eventually to the 50 ohm input (or a 75 ohm input) of your radio.
Basically the cable is "different" from the antenna electrically and so they need to "match up" to each other as best they can to produce the best signal to the radio. You will find explanations on the websites below. For anyone who remembers, often tvs would have a balun where the cable from the tv antenna would connect to the back of the tv. These are different ones but thats what a balun is. This however is an un-un, but it is a similar kind of thing. (a balun means "balanced to balanced" whereas an un-un means "unbalanced to unbalanced".
The coaxial cable I am using is called 50 Ohm RG-58C/U. You can get this at an electronics store. It might have a slightly different name but just make sure its 50 ohm and called something like rg-58. You could use other 50 ohm coaxial cables (made for hf) but they are much more expensive. They are better than the rg-58, as they don't lose as much signal, but if you need a fair bit in length, I personally choose the cheaper. It is normally suggested that people choose the better one if they need it quite long (over 30 metres?), to avoid losing as much signal strength, but even then, I personally would choose the cheaper one....but thats just my preference. Feel free to choose what you would prefer.
You will also need some plugs to connect the coaxial cable to the un-un and to the radio. The plugs you need depends on what your radio and un-un use. I use a pl-259 (also called a uhf connector - even though we are using it for hf and not UHF....don't worry....its just the name :) ) as this fits my hf receiver, and a BNC connector for connecting to the un-un.
For the 7.5 metre horizontal part of the antenna, I used plastic coated, hard but bendable wire (from a hardware store). Again, others might prefer copper wire or stranded wire etc. but this is what I am using just now, and one day I might try something else.
I stripped back some of the plastic coating to leave maybe 4 centimetres of bare wire exposed on each end. I then put some hose clamps (used for clamping garden hoses) on the ends of the aluminium poles. I then placed the exposed ends of the wire between the clamps and the poles and tightened the clamps. ( I will put tape over these areas eventually to weatherproof them too).
At the bottom I connected a small wire (same type of wire - but doesn't have to be) to the bottom of the "front" (north) pole and connected it to the "antenna" wingnut of the un-un. (This is just one side of the un-un and it is where the antenna goes. The other part of the un-un is to take a wire from it to the ground.
I connected a wire from the "ground" wingnut of the un-un, to a ground rod ( a metal pole I put into the ground - I used copper, but only because there was some in the house when we came to live here - it can be a bit expensive if you have to buy it though - although depending on who you talk to, copper is normally seen as the best for lightening protection... please read up on safety when it comes to proper ground rods, i.e. what to use and how to go about putting them into the ground. Please don't just use whatever you have until you have asked an expert. I use some galvanised steel for other ground rods (I haven't tried them with a EWE though) but these are for low antennas. I honestly don't know if they are good to use or not as there is no copper coating on them at all and usually copper is advised. Maybe someone else can write a post on what you can use for ground rods (and their length). I think my ground rods are around 3 feet long each. Normally people use 8foot long ground rods for grounding antennas,
but for this antenna I used the copper I had and it works great (for reception - for lightening protection it might be another story). It is normally adviseed to also put another ground rod below the place where your coaxial cable will eventually enter your building. You might want to make this one longer and use this one more for protection, although really every rod should be used also for protection.
The coax plugs into the unun and leads back to my radio.
At the other end, a clamp at the bottom of the rear (south) pole clamps a wire that goes to one connector on a variable resistor (potentiometer) ( You can get these at Electronics stores) (I am using a 1kohm variable resistor - If you have harder soil or dry conditions, you might want a 2kohm variable resistor). Again, you don't need to know about resistors etc., just to know that a variable resistor is easier to use than a normal resistor because you can adjust it to find the best "resistance value". Another wire goes from another connector of the variable resistor, to a clamp on another ground rod in the ground.
One thing that concerned me was that about 4 metres away from the front of the antenna, is a concrete wall of a couple of metres height and a small metal fence above that. Behind the concrete is earth, as the house next door is up higher than our house. I don't know what effect this is having on reception and whether it makes reception of "lower angled" signals, less likely than higher angled signals, but I put the antenna as far away from it as I thought was the most I could due to the fact that most of the area below the 7.5m wire, is concrete, and I didn't want the pole to be over concrete.I have wondered whether the concrete below will affect the performance , and I briefly tried a kind of "couterpoise" (this is simply connecting a wire to the ground connections at both ends of the antenna and having this wire run below the 75m wire and on top of the concrete), but I decided it wasn't necessary, as I was still getting good results the next day without it. I might still look into this and test a counterpoise again, and then decide how best to place it if I decide to have one. I don't really want a wire running along the concrete where it might trip someone up, and look a bit ugly too.
Test results.
After I set everything up I did some testing.
I haven't done much testing so far with the resistor value but I looked up broadcast band frequencies that are from stations to the south west of me ( in fact its closer to west south west), and one so happened to be the same frequency as I was hearing a station in the North (although possibly from a relay). This was 720khz. I should say though, that I think the northern station was actually an "accidental" broadcast ( these are like fainter images of the proper broadcast on another frequency that are accidentally broadcast in other parts of the radio band).
I tuned it on the radio and heard the cutting in/out sound of both stations. It was hard to make out things being said because they both were interfering with each other. I turned the radio's volume up, so that I could hear it where I have the antenna and I walked over to the back end of the EWE and slowly turned the knob of the variable resistor. As I did it, the west-south-west station reduced in strength and then disappeared totally, and the northern station was clear and strong. The fact that the unwanted signal was coming from the west south west instead of from direct south, shows either the strength of the Koontz design at reducing rear signals- even from west south west etc., or it is possible that other nearby objects in my backyard are affecting the directionality as well. In any case, it is interesting that the signal from west south west could be entirely blocked by turning the variable resistor. The page at http://www.ok1rr.com/e107_plugins/content/content.php?content.114 shows what is called an Azimuth pattern. This in a way shows the EWE's strength of reception from different directions. As you can see, most of the part behind 90 and 170 degrees, is weaker than the signal from above. It will take me some time to find the best point on the resistor for HF (shortwave), but I will spend some time soon trying to find that.
Unfortunately my longwire antenna is fed (i.e. connected to some coaxial cable) through to a room upstairs and so I couldn't quickly compare results or directions of signals, but I suddenly noticed that with the EWE, I was now receiving lots of Japanese signals...much more than I usually receive. ( I personally listen more to what are called Utility stations, and these are often weaker than broadcast stations.)
I am in New Zealand, so Asia is to the north (or north west). I was hearing a lot of utility stations I had never heard before, and while I was still picking up stations from the other side of the world, I think these were taking the path from the North to get to me. Russian frequencies were coming in nicely too (again - these were not hearable on the longwire/beverage at all). Comparing it to the other antenna, it wasn't just due to noise that I wasn't picking them up. I couldn't even hear the stations transmitting, on the long./bev but the EWE was giving me a strong signal with no (or little) noise. It is possible that some of these stations might have become hearable if the longwire bev was higher in the air for more of its' length, or pointed in a different direction, but I will eventually reverse the connections on the EWE and let you know if the south suddenly becomes hearable instead of the north.
I was mainly tuning around 6 mhz, 8mhz and 9mhz but around 2,3 and 4 mhz, it was noisier and I didn'thear much (in terms of utility stations). This was mainly due to the fact that I only tried for a few minutes, as I have less interest in these areas (not that they are less interesting, but just that I spend less time bothering tuning there). It was probably/possibly that there was nothing transmitting when I was tuning. The noise may also have been noticed because I had had such good reception around 5-10 mhz etc. that I naturally felt disappointed when I briefly tried 2,3,4 mhz. Also, these areas are known to be noisy compared to higher areas, and that is why the EWE was made with these areas in mind. I personally don't have a lot of experience tuning 2 and 3 mhz, but I know it is harder to pick up signals in these areas due to the higher noise levels.
At the moment it is raining here and I am not getting the chance to dig little holes to pour some concrete in to support the antenna. I am going to put pvc pipes into the concrete to act as sleeves for the antenna poles. I am going to put other pvc pipes over the bottom parts of the poles and these will slot into the sleeves. I am also going to put some wooden poles inside them too and connect some ropes to act as guy ropes to further support the poles. These ropes will be pegged into the ground. This will allow me to take the antenna down at any point and keep the backyard relatively "normal" looking when its not needed ( although I am sure I will probably be wanting the antenna up most of the time :) ). With this method though I should be able to take it down before any strong winds are forecast...just in case.
I have added the next bit ( done a few days later) to this post so that all of the results and pictures are together. The rest of it can be seen in the later post.
Ok, today I have put the EWE up again, but this time I have faced it southwards, pointing in between South America and Africa (if you picture going "from" New Zealand, down through the Antarctic, and up the other side of the globe).
Here are some pictures of the bits and pieces I am using:
These are the alluminium poles:
http://img573.imageshack.us/i/dscf3582g.jpg/
Here they are again with the 7.5 metre wire attached by the hose clamps:
http://img31.imageshack.us/i/dscf3579t.jpg/
The next picture shows the bottoms of both poles, with the hose clamps on and with the wire that will go to the antenna wingnut of the un-un (I have this wire on already because the pole is going into the box of wood and it would be impossible to put it on once its in:
http://img691.imageshack.us/i/dscf3580a.jpg/
Here is the back end, in position, balanced/held up by wood and a wooden chair:
http://img340.imageshack.us/i/dscf3583h.jpg/
This shows the bottom of the rear pole, with a wire from it going to the variable resistor (or called potentiometer), and a wire from another connector of the variable resistor going to the hose clamp on the ground rod:
http://img337.imageshack.us/i/dscf3584o.jpg/
Note in the picture above I have two wires going to the rod. This is not required. I had to do this originally to allow me to have one wire to the ground rod and the other connected to another wire that ran along the ground (directly underneath the horizontal 7.5 metres wire) and joined up to the ground rod at the other pole. This wire was 7.5 metres too. This is the counterpoise I mentioned that I tried just in case the concrete was affecting things. I don't know if a counterpoise (if used) has to go straight to the other end or if it can go off at an angle and then come back to the other ground rod. I had originally thought I would need one because the original idea meant that one vertical would be coming down to concrete-not soil, so I thought I would need it, but I have since changed the plan and now both ends are above soil.
This next picture shows the wire from the Variable Resistor fastened to the ground rod by the hose clamp (the ground rod clamps are bigger than the others due to the rod being wider than the antenna poles.)
http://img402.imageshack.us/i/dscf3587c.jpg/
Here is a close up of the Variable resistor. The middle one doesn't have to go through that little hole by the way. I just did it that way. Also, it doesn't have to be soldered in this order. I was thinking afterwards I wanted to put the antenna wire on one of the end connectors of the variable resistor, but I had already done it this way and I looked it up to make sure this was ok and it supposedly is, so thats ok. It just depends what way you want to turn the variable resistor, to get higher blocking of signals coming from directions behind the rear of the antenna.
http://img600.imageshack.us/i/dscf3588v.jpg/
This shows the bottom of the rear pole:
http://img98.imageshack.us/i/dscf3589.jpg/
This is the "front end" of the antenna. The front pole goes into the box at the top of the picture, and a wire that is clamped to the bottom of this pole, pokes out of that little hole at the bottom (on the side) of the box. This wire then connects to the antenna wignut of the un-un, which is pictured on the piece of wood (with the coaxial cable connected, running back to the radio - which is stuck in between bushes :) )
http://img602.imageshack.us/i/dscf3590.jpg/
This shows the same:
http://img233.imageshack.us/i/dscf3591r.jpg/
Here is the rear pole after the front end has been put up too :
http://img714.imageshack.us/i/dscf3595s.jpg/
This is taken from behind the rear pole, showing the front pole (hard to see) in the distance. This also shows the direction it is pointing. You can see the water in the distance. Thats the Pacific Ocean, and after that its Antarctica and then between South America and South Africa.
http://img255.imageshack.us/i/dscf3596.jpg/
This shows the front pole in the box of wood:
http://img220.imageshack.us/i/dscf3598e.jpg/
This shows the front pole (side on), and where the radio had to be to test it - the coax cable was only long enough for there, so I had to sit half in between some bushes - some of which was Blackberry with thorns :(
http://img59.imageshack.us/i/dscf3608.jpg/
This shows it side on after it was all up:
http://img508.imageshack.us/i/dscf3612.jpg/
This is just before I pulled it down again. It was getting dark and a bit cold, so I decided to stop:
http://img521.imageshack.us/i/dscf3613d.jpg/
Todays results:
A funny story first. I had everything set and I turned on the receiver (which wouldn't go at first...a thing that can happen with frg-8800s when unplugged, and so I had to take a battery [used for keeping the memory of frequencies] out (which resets things), and tried the AM broadcast band. I thought "I wonder if this will now block out the bigger radio stations (that come from the North Island of NZ) and be stronger on the ones down south west?"
I turned the radio's tuning knob and there was hardly anything showing up. Even the big stations were weak and had noise.
I was excited, and thought "Wow, this antenna blocks rear signals better than I thought it could".
While I was pleased, it just didn't feel right...so I looked around and checked everything.....and all seemed fine....so I dis-connected the coaxial cable and there was no change in sound. I thought I must have damaged my radio when I accidentally pulled the power cord and pulled the radio a bit off of the little step ladder it was on. Then I looked, and saw that I had had the cable plugged into the wrong socket :)
The radio also has a socket for an antenna to listen to the vhf airband and I had plugged the ewe into that by mistake. The radio was in the garden and so I had had to plug the cable in while standing in front of it (i.e. instead of being behind the radio and plugging it in with the socket visibly in front of me).
I quickly changed it and the broadcast band was back to normal.
It did however still weaken rear signals like the other day, but now in reverse i.e. blocking north stations because I had now pointed the antenna south instead of north. Of course the northern stations were still there ( seeing as they are from New Zealand), and also because I think they are all rebroadcast anyway from a mountain in Dunedin where I live, so there wasn't really any way of blocking them :) ....even by plugging into the wrong socket.
Anyway, I had a quick tune around but it was afternoon, so no real chance of hearing any other countries' AM broadcast band stations. I tried later when it got darker, but not for long, but didn't hear anything really. There were a couple of things I wasn't sure about but they were probably NZ stations.
I'm not really an AM (called broadcast or MW band) person anyway (although when I get the ewe up properly I think I will enjoy trying it at night for other countries' normal local AM stations.
HF (shortwave)
I was really wanting to try hf, so I tuned around in the afternoon and I was getting loads of Spanish speaking shortwave broadcast stations. It was very sunny here (for any new radio people - the sun's position in the sky affects which radio waves get to you and which ones don't, from other countries)(I can't be sure of the time- I just know I was getting hot) and yet I was getting some great signals. I was even getting them around 6 mhz (and lower? ..I can't remember) ( normally during daytime, transmissions from overseas are on higher frequencies, and when night they go to lower frequencies). I don't listen a lot to shortwave broadcast stations, so I cannot say for sure if the antenna was responsible or not, but it seemed so much of a coincidence that most were Spanishy sounding and no ( or nearly no) strong noticable Asian stations (i.e. as I tuned, nothing jumped out strongly that was Asian..) Maybe I was telling myself that everything was Spanishy but I also got something that sounded possibly from the Caribbean, and some Middle Eastern/African sounding etc. I also possibly hearing European things too I think. It wasn't so much what I heard ( although that was convincing me that the antenna was really working superbly), but what I "didn't" hear. I wasn't noticing Asian stations.
When I tried tuning for utility stations ( aircraft etc. ) and amateur radio areas, again, I only heard Asian things a few times. The other day, nearly everything seemed Japanese. I came across various Atlantic civil aviation frequencies like Santa Maria and Gander. I didn't hear any Asian aviation freqs, although strangely I did have San Francisco coming in ok. I don't know what path the San Fransisco signal was taking to reach me. It could have come to the front of the antenna, but it might have simply been from the back. I suppose I shouldn't expect the antenna to be blocking out everything from behind it. I never used to expect that. Its just since the other day and the seemingly fantastic directionality I was getting, you then start to expect no rear signals at all :) (Well, not really expecting that, but you get a bit disappointed when you hear something from behind.)
Variable Resistor:
Throughout today, I went back and forth, adjusting the variable resistor value ( how much the knob is turned ), to see what would happen. Sometimes, not a lot happened, probably because the noise was from the same direction as the wanted signal.
Some stations however, you really noticed funny things happening.
I heard a utility station which sounded Spanishy, but I found that the signal strength increased when I turned the knob the "other" way (i.e. the way to have not so much blocking of rear signals).
I think the station might actually have been from the Phillipines or somewhee else in Asia, and thats why it was Spanish.
I know for certain though, after today's and the other day's testing, that the variable resistor really does work and really does weaken rear noise and signals/ and increase the signal from in front.
Hopefully this hasn't been too long, and has been helpful to someone. I'll try and answer any questions anyone has, and maybe some others who use EWEs will give some insights into how they get theirs to be the best they can get them to receive.
Can I ask a favour of people replying to this post? :)
Just to keep the forum posts tidy for people wanting to read only about the EWE antenna, could people who want to give their opinions on other types of antennas, please start seperate threads for each type of antenna design? I am sure people would love to read the views of people who know a lot about other designs and how they compare with or are better than the EWE, but just to keep things tidy, it would be great if this thread could just be about the EWE.
Thanks for that in advance. :)
The main sources of info which my explanations are based on for the workings of the ewe, are the following:
http://www.dxing.info/equipment/ewe.dx
http://www.ok1rr.com/e107_plugins/content/content.php?content.114
and for a switching version between 4 or more EWE's:
http://www.ok1rr.com/e107_plugins/content/content.php?content.115
Other understandings were gained from various sources over time like Marc Robinson (VK2BUA), in an article in Amateur Radio magazine, reprinted in Break In magazine, concerning static and terminations.
Last edited by db1 at Sunday, 09-Jan-11 12:28:26 UTC
Last edited by db1 at Monday, 10-Jan-11 12:20:42 UTC
Message from Calico at Thursday, 06-Jan-11 17:52:57 GMT
Thank you for taking the time, please expand and add anytime.
Ewes being great antennas, can also be ground dependent, so I was wondering what your observations/findings may have been from your experimentation re. this. Some folks add radials for example to enhance reception, but your ground conductivity may be good?
Also, what preamplifier (make and dB) have you found to work for you?
Edit: OK, no external preamplifier mentioned in your posting, so does your radio have a preamp? What radio by the way?
Here using 2 cascaded (if need be) preamps, trying to avoid hi-gain if at all possible.
Waters and Stanton (among others) sell an interesting one for only £12.00
http://www.wsplc.com/acatalog/TT-1001_Broadband_RF_pre-amplifier.html
Importantly, can you expand a bit more on the impedance transformer you are using there, commercial or home brewed etc ? Have you found a way perhaps to measure roughly what your feed-point impedance at some range of freqs?
It would be really great,if you one day you found the time to possibly post photos of your antenna to photobucket.com or similar.
73 and thanks again for the posting :-)
Tim
Last edited by Calico at Thursday, 06-Jan-11 18:16:20 UTC
Ewes being great antennas, can also be ground dependent, so I was wondering what your observations/findings may have been from your experimentation re. this. Some folks add radials for example to enhance reception, but your ground conductivity may be good?
Also, what preamplifier (make and dB) have you found to work for you?
Edit: OK, no external preamplifier mentioned in your posting, so does your radio have a preamp? What radio by the way?
Here using 2 cascaded (if need be) preamps, trying to avoid hi-gain if at all possible.
Waters and Stanton (among others) sell an interesting one for only £12.00
http://www.wsplc.com/acatalog/TT-1001_Broadband_RF_pre-amplifier.html
Importantly, can you expand a bit more on the impedance transformer you are using there, commercial or home brewed etc ? Have you found a way perhaps to measure roughly what your feed-point impedance at some range of freqs?
It would be really great,if you one day you found the time to possibly post photos of your antenna to photobucket.com or similar.
73 and thanks again for the posting :-)
Tim
Last edited by Calico at Thursday, 06-Jan-11 18:16:20 UTC
Message from db1 at Friday, 07-Jan-11 03:54:34 GMT
Hi Calico,
Thanks for your message.
My ground seems to be quite good. We get a lot of rain here. I also filled the ground rod areas with water as I was putting them in, to help them go in easier. I have read other people saying that they probably have neighbours wondering why they are watering a ground rod :)
I wondered about the ground for another reason as well. The back end is near an end point of our garden and there is then a metre or so drop down to the neighbours place behind. I decided to place the ground rod in a bit from this edge (a foot or two sideways from the back pole) just to make sure things weren't affected. I wasn't sure if a EWE ground would work best with equal space round each pole, or if it was fine as long as there was a bit a space in some direction, and it was good at conducting.
My radio is an FRG-8800 and it doesn't have a pre-amp built in. Thanks for the link to the preamp. I will have a look at that.
I originally wanted to be able to use all 4 EWEs at the same time, on 4 different receivers. I have two 8800s, an frg-7, and a portable National Panasonic (I can't remember the number).
I drew up a plan to allow me to have all four receivers, able to switch between any of the antennas ( and maybe a longwire). I haven't got around to doing this yet, but I have a few rotary switches (and some normal switches) that I would use together to allow the 4rxs to use the 4 (or 5 different antennas) and also to allow 2 or more receivers to share the same antenna if I need to listen to 2 frequencies from the same part of the world, at the same time. This was one reason why I wanted a pre-amp, so that I could share an antenna between 2 or more receivers, but keep the signal strength up. I was going to make a splitter that would share the signal without interfering with each rx.
The switching thing took a bit of figuring out. I looked around on the internet and radio shops but no-one had anything to do this except big military ones :). A man told me that it would cost a lot to get someone to make something like that, so I decided to get some rotary switches and work out the different possible switching settings of them and work out a (slightly round about) way of getting it to work.
Concerning the transformer, I am using a "QB-9E End-fed UNUN/10w" (50 ohm to 450 ohm) (as far as I remember, this would be a 9:1 transformation) made by Erickson Engineering. The man who made it stopped soon after. He later sold on ebay but has gone again. I am wanting to get some more if I can as they are great units and at a cheap price. (I can't remember the price though). It is very sturdy and is rectangular in shape. Even though the core is protected inside the casing, I am going to put it into a larger box and tape the box up and put some silicon on the entry and exit points ( although I did this for my previous ewe and moisture still got in and made a bit of a mess, although the unun was probably ok still.)
I haven't measured the impedance of different frequencies as unfortunately I don't have the equipment to do this.
I might take some pictures or videos of putting the antenna together when I put it up properly. The rain has just cleared up, so I might go out today and have a look at where exactly I should put some holes for the concrete base.
What were you meaning about avoiding high gain? Were you meaning about overloading the rx?
db1 (David)
Thanks for your message.
My ground seems to be quite good. We get a lot of rain here. I also filled the ground rod areas with water as I was putting them in, to help them go in easier. I have read other people saying that they probably have neighbours wondering why they are watering a ground rod :)
I wondered about the ground for another reason as well. The back end is near an end point of our garden and there is then a metre or so drop down to the neighbours place behind. I decided to place the ground rod in a bit from this edge (a foot or two sideways from the back pole) just to make sure things weren't affected. I wasn't sure if a EWE ground would work best with equal space round each pole, or if it was fine as long as there was a bit a space in some direction, and it was good at conducting.
My radio is an FRG-8800 and it doesn't have a pre-amp built in. Thanks for the link to the preamp. I will have a look at that.
I originally wanted to be able to use all 4 EWEs at the same time, on 4 different receivers. I have two 8800s, an frg-7, and a portable National Panasonic (I can't remember the number).
I drew up a plan to allow me to have all four receivers, able to switch between any of the antennas ( and maybe a longwire). I haven't got around to doing this yet, but I have a few rotary switches (and some normal switches) that I would use together to allow the 4rxs to use the 4 (or 5 different antennas) and also to allow 2 or more receivers to share the same antenna if I need to listen to 2 frequencies from the same part of the world, at the same time. This was one reason why I wanted a pre-amp, so that I could share an antenna between 2 or more receivers, but keep the signal strength up. I was going to make a splitter that would share the signal without interfering with each rx.
The switching thing took a bit of figuring out. I looked around on the internet and radio shops but no-one had anything to do this except big military ones :). A man told me that it would cost a lot to get someone to make something like that, so I decided to get some rotary switches and work out the different possible switching settings of them and work out a (slightly round about) way of getting it to work.
Concerning the transformer, I am using a "QB-9E End-fed UNUN/10w" (50 ohm to 450 ohm) (as far as I remember, this would be a 9:1 transformation) made by Erickson Engineering. The man who made it stopped soon after. He later sold on ebay but has gone again. I am wanting to get some more if I can as they are great units and at a cheap price. (I can't remember the price though). It is very sturdy and is rectangular in shape. Even though the core is protected inside the casing, I am going to put it into a larger box and tape the box up and put some silicon on the entry and exit points ( although I did this for my previous ewe and moisture still got in and made a bit of a mess, although the unun was probably ok still.)
I haven't measured the impedance of different frequencies as unfortunately I don't have the equipment to do this.
I might take some pictures or videos of putting the antenna together when I put it up properly. The rain has just cleared up, so I might go out today and have a look at where exactly I should put some holes for the concrete base.
What were you meaning about avoiding high gain? Were you meaning about overloading the rx?
db1 (David)
Message from vk4fsgw at Friday, 07-Jan-11 09:34:18 GMT
Hi Dave, interesting thread here. I have experimented in EWE's but not a great deal of success, probably did not take time in setting 1 up. The other interesting thing is that you have the yaesu frogs 8800 and 7. Maybe you could add one on here (frg8800) at globaltuners. Not sure how much knowledge you have in electronics, but here is a simple circuit to build for the CAT system.URL is
http://francokok.com/index.php?option=com_content&view=article&id=46&Itemid=54&lang=en
Although these old receivers do not allow for any fancy button or stuff to be controlled, it can be done with ease.
I have made quiet a few of these CAT or C-IV's up to suit my frg and icoms. If you need help with it, just drop us an email or support blog.
Cheers
Steve
Last edited by vk4fsgw at Friday, 07-Jan-11 09:35:07 UTC
http://francokok.com/index.php?option=com_content&view=article&id=46&Itemid=54&lang=en
Although these old receivers do not allow for any fancy button or stuff to be controlled, it can be done with ease.
I have made quiet a few of these CAT or C-IV's up to suit my frg and icoms. If you need help with it, just drop us an email or support blog.
Cheers
Steve
Last edited by vk4fsgw at Friday, 07-Jan-11 09:35:07 UTC
Message from Calico at Friday, 07-Jan-11 09:56:37 GMT
Hi there David and Steve,
Reading with great interest here what you write about this antenna, as another friend here from the Pacific coast and myself are flirting with Ewes (pun intended). Let me quickly make very clear that I am not at all knowledgeable here either, just addicted to radio like most of us here :-)
The proof of the pudding is in the eating, and if your Ewe gives you good results towards Japan then there are good things happening!
Small garden here too, so beverages remain a dream, hence trying to do as much as I can with various kinds of loops, active, passive, small or big aperture, flags pennants , etc, but since you are so pleased with the Ewe, I will try it too very soon, have got all the hardware needed, let’s see if I will have the results needed. Maybe it can mow the lawn too by the way ?
:-)
What is interesting with the (two!) FRG-8800s is that they very conveniently for a Ewe antenna have Hi-z 500 Ohm antenna connectors (next to the 50 Ohm one). Which lends itself nicely for connecting directly the antenna to the radio, cheaper and with lower losses!
Probably you must have already used the Hi-z connectors, I wonder what your impressions are?
Re. the preamps....necessary evil, I suppose. LW/MW bands on ham radios are usually purposefully attenuated for front end and mixing product reasons. So that’s no good for a start for MW dx-ing, Then the Ewe, Flags etc are small antennas in proportion to the wavelengths we use them for (600m wavelength at 500 k/c)…low signal yield so a preamp can help a lot. Challenge is that preamps not only introduce their own noise, but also raise the noise floor of an otherwise settled radio, and this can drown weak dx signals, catch-22 sometimes :- (
Thinking of making the Π (ewe) here with two fishing rods and a ground rod at the bottom of each. Then by swapping which end is grounded and which is attached to the unun, I can cover E-W / W-E with one set of poles. If it works, I will get another pair up for SE/NW to be able to improve RNZI on 9870 :-)
Panasonic / National used to do great little portables, what a pity they don’t anymore. Playing with an RF-B65 here at the moment, what a gem! If only, as is the case with normal radios...it had a connector for an external antenna!
73 from foggy UK ,
Tim
Reading with great interest here what you write about this antenna, as another friend here from the Pacific coast and myself are flirting with Ewes (pun intended). Let me quickly make very clear that I am not at all knowledgeable here either, just addicted to radio like most of us here :-)
The proof of the pudding is in the eating, and if your Ewe gives you good results towards Japan then there are good things happening!
Small garden here too, so beverages remain a dream, hence trying to do as much as I can with various kinds of loops, active, passive, small or big aperture, flags pennants , etc, but since you are so pleased with the Ewe, I will try it too very soon, have got all the hardware needed, let’s see if I will have the results needed. Maybe it can mow the lawn too by the way ?
:-)
What is interesting with the (two!) FRG-8800s is that they very conveniently for a Ewe antenna have Hi-z 500 Ohm antenna connectors (next to the 50 Ohm one). Which lends itself nicely for connecting directly the antenna to the radio, cheaper and with lower losses!
Probably you must have already used the Hi-z connectors, I wonder what your impressions are?
Re. the preamps....necessary evil, I suppose. LW/MW bands on ham radios are usually purposefully attenuated for front end and mixing product reasons. So that’s no good for a start for MW dx-ing, Then the Ewe, Flags etc are small antennas in proportion to the wavelengths we use them for (600m wavelength at 500 k/c)…low signal yield so a preamp can help a lot. Challenge is that preamps not only introduce their own noise, but also raise the noise floor of an otherwise settled radio, and this can drown weak dx signals, catch-22 sometimes :- (
Thinking of making the Π (ewe) here with two fishing rods and a ground rod at the bottom of each. Then by swapping which end is grounded and which is attached to the unun, I can cover E-W / W-E with one set of poles. If it works, I will get another pair up for SE/NW to be able to improve RNZI on 9870 :-)
Panasonic / National used to do great little portables, what a pity they don’t anymore. Playing with an RF-B65 here at the moment, what a gem! If only, as is the case with normal radios...it had a connector for an external antenna!
73 from foggy UK ,
Tim
Message from db1 at Saturday, 08-Jan-11 00:23:28 GMT
Hi again,
Thankyou Steve for the offer of help and the webpage. I have a CAT for the 8800 already. I bought one off of someone in the UK who makes them. I might try making one (from the page you sent me) sometime, for the other 8800 though.
Tim, to tell the truth, I hadn't thought about trying the hi-z input for the EWE :) I naturally just went to the coax. I have used the high z for other wires I have tried out, but didn't think to test it when I started testing this ewe. Maybe I'll try that too. It will need coax eventually anyway though, as I have to lead the feed through a window and through and along a metal frame, but at the moment I am only testing near the antenna, so I could probably try it some time.
Good idea about the fishing rods too. It'll be great to hear your results.
Concerning the 8800s, I had one (second hand) and I thought that a particular piece of software wasn't able to work with it, so I planned on getting another receiver to allow it to work. I wanted to get an Icom r-71, but didn't get the right opportunities and then I saw another 8800 come up for 2nd hand sale online here in NZ, so I bought it. With utility listening, I like to be able to have different freqs on at the same time or have 2 radios scanning different freqs. Anyway, I later realised that the software did work with the radio, but just not as the software was meant to. I had to type in the freqs to scan (in the programme) in a backwards kind of way (due to the way the 8800 has it's computer code).
It would be nice to be able to put one on Globaltuners, and maybe one day I might try it, but there are a few things in the air about that. I was thinking of maybe giving my radio to someone I know who has expressed an interest in radios. I have to wait and see about that though.
Also, I share the internet connection with my family and we have a set download/upload limit. Maybe I could give it a try some time and see how it goes though for a short time.
Ok, I am just about to put the antenna up again (until I pur some concrete I am supporting the poles with a wooden chair at one end and a cardboard box full of firewood at the other end :) ) Hence the reason I haven't been leaving it up over night.
By the way, I should have made it clearer in my other post that I am not going to have any part of the pole going into the sleeve in the concrete. It will just be the pvc going into it and the antenna will start be just above the level of the ground. I re-read what I had written and it kind of sounded like the bottom part of the poles would be below the level of the ground.
I might take some pictures of the parts and of it getting put up, and put it online somewhere. I think I'll try pointing it south too, and hopefully (fingers crossed) hear stronger South Americans (and less signal strength from Asia) etc. - although it will kind of be pointing right in between South America and Africa.
db1
Thankyou Steve for the offer of help and the webpage. I have a CAT for the 8800 already. I bought one off of someone in the UK who makes them. I might try making one (from the page you sent me) sometime, for the other 8800 though.
Tim, to tell the truth, I hadn't thought about trying the hi-z input for the EWE :) I naturally just went to the coax. I have used the high z for other wires I have tried out, but didn't think to test it when I started testing this ewe. Maybe I'll try that too. It will need coax eventually anyway though, as I have to lead the feed through a window and through and along a metal frame, but at the moment I am only testing near the antenna, so I could probably try it some time.
Good idea about the fishing rods too. It'll be great to hear your results.
Concerning the 8800s, I had one (second hand) and I thought that a particular piece of software wasn't able to work with it, so I planned on getting another receiver to allow it to work. I wanted to get an Icom r-71, but didn't get the right opportunities and then I saw another 8800 come up for 2nd hand sale online here in NZ, so I bought it. With utility listening, I like to be able to have different freqs on at the same time or have 2 radios scanning different freqs. Anyway, I later realised that the software did work with the radio, but just not as the software was meant to. I had to type in the freqs to scan (in the programme) in a backwards kind of way (due to the way the 8800 has it's computer code).
It would be nice to be able to put one on Globaltuners, and maybe one day I might try it, but there are a few things in the air about that. I was thinking of maybe giving my radio to someone I know who has expressed an interest in radios. I have to wait and see about that though.
Also, I share the internet connection with my family and we have a set download/upload limit. Maybe I could give it a try some time and see how it goes though for a short time.
Ok, I am just about to put the antenna up again (until I pur some concrete I am supporting the poles with a wooden chair at one end and a cardboard box full of firewood at the other end :) ) Hence the reason I haven't been leaving it up over night.
By the way, I should have made it clearer in my other post that I am not going to have any part of the pole going into the sleeve in the concrete. It will just be the pvc going into it and the antenna will start be just above the level of the ground. I re-read what I had written and it kind of sounded like the bottom part of the poles would be below the level of the ground.
I might take some pictures of the parts and of it getting put up, and put it online somewhere. I think I'll try pointing it south too, and hopefully (fingers crossed) hear stronger South Americans (and less signal strength from Asia) etc. - although it will kind of be pointing right in between South America and Africa.
db1
Message from Calico at Saturday, 08-Jan-11 02:48:42 GMT
Ok David,
Two points I meant to ask you:
1) Have you experimented with different vertical lengths to find some optimum antenna response to incoming MW frequency signals?
I mean *IF* the two vertical legs of the antenna function similar to a phased array, have you perhaps tried/experimented with different length combinations? How did you arrive to and finalize the lenghts of the legs/horizontal wire?
2) In the first posting, a 75 m counterpoise was mentioned. Did this counterpoise run in any specific direction/compass bearing, or was it laid in a random direction more or less?
Will keep you posted with any results this end when I get round to running any tests, all is done under the cover of the night due to planning permission issues and "good Samaritans" in the neighborhood.
Don't want to make this thread a dialogue mostly between you and me, so I will take a step back in case someone else wants to discuss the antenna with you.
73 es gd dx
Tim
Two points I meant to ask you:
1) Have you experimented with different vertical lengths to find some optimum antenna response to incoming MW frequency signals?
I mean *IF* the two vertical legs of the antenna function similar to a phased array, have you perhaps tried/experimented with different length combinations? How did you arrive to and finalize the lenghts of the legs/horizontal wire?
2) In the first posting, a 75 m counterpoise was mentioned. Did this counterpoise run in any specific direction/compass bearing, or was it laid in a random direction more or less?
Will keep you posted with any results this end when I get round to running any tests, all is done under the cover of the night due to planning permission issues and "good Samaritans" in the neighborhood.
Don't want to make this thread a dialogue mostly between you and me, so I will take a step back in case someone else wants to discuss the antenna with you.
73 es gd dx
Tim
Message from db1 at Saturday, 08-Jan-11 16:00:43 GMT
Ok, today I have put the EWE up again, but this time I have faced it southwards, pointing in between South America and Africa (if you picture going "from" New Zealand, down through the Antarctic, and up the other side of the globe).
Here are some pictures of the bits and pieces I am using:
These are the alluminium poles:
http://img573.imageshack.us/i/dscf3582g.jpg/
Here they are again with the 7.5 metre wire attached by the hose clamps:
http://img31.imageshack.us/i/dscf3579t.jpg/
The next picture shows the bottoms of both poles, with the hose clamps on and with the wire that will go to the antenna wingnut of the un-un (I have this wire on already because the pole is going into the box of wood and it would be impossible to put it on once its in:
http://img691.imageshack.us/i/dscf3580a.jpg/
Here is the back end, in position, balanced/held up by wood and a wooden chair:
http://img340.imageshack.us/i/dscf3583h.jpg/
This shows the bottom of the rear pole, with a wire from it going to the variable resistor (or called potentiometer), and a wire from another connector of the variable resistor going to the hose clamp on the ground rod:
http://img337.imageshack.us/i/dscf3584o.jpg/
Note in the picture above I have two wires going to the rod. This is not required. I had to do this originally to allow me to have one wire to the ground rod and the other connected to another wire that ran along the ground (directly underneath the horizontal 7.5 metres wire) and joined up to the ground rod at the other pole. This wire was 7.5 metres too. This is the counterpoise I mentioned that I tried just in case the concrete was affecting things. I don't know if a counterpoise (if used) has to go straight to the other end or if it can go off at an angle and then come back to the other ground rod. I had originally thought I would need one because the original idea meant that one vertical would be coming down to concrete-not soil, so I thought I would need it, but I have since changed the plan and now both ends are above soil.
This next picture shows the wire from the Variable Resistor fastened to the ground rod by the hose clamp (the ground rod clamps are bigger than the others due to the rod being wider than the antenna poles.)
http://img402.imageshack.us/i/dscf3587c.jpg/
Here is a close up of the Variable resistor. The middle one doesn't have to go through that little hole by the way. I just did it that way. Also, it doesn't have to be soldered in this order. I was thinking afterwards I wanted to put the antenna wire on one of the end connectors of the variable resistor, but I had already done it this way and I looked it up to make sure this was ok and it supposedly is, so thats ok. It just depends what way you want to turn the variable resistor, to get higher blocking of signals coming from directions behind the rear of the antenna.
http://img600.imageshack.us/i/dscf3588v.jpg/
This shows the bottom of the rear pole:
http://img98.imageshack.us/i/dscf3589.jpg/
This is the "front end" of the antenna. The front pole goes into the box at the top of the picture, and a wire that is clamped to the bottom of this pole, pokes out of that little hole at the bottom (on the side) of the box. This wire then connects to the antenna wignut of the un-un, which is pictured on the piece of wood (with the coaxial cable connected, running back to the radio - which is stuck in between bushes :) )
http://img602.imageshack.us/i/dscf3590.jpg/
This shows the same:
http://img233.imageshack.us/i/dscf3591r.jpg/
Here is the rear pole after the front end has been put up too :
http://img714.imageshack.us/i/dscf3595s.jpg/
This is taken from behind the rear pole, showing the front pole (hard to see) in the distance. This also shows the direction it is pointing. You can see the water in the distance. Thats the Pacific Ocean, and after that its Antarctica and then between South America and South Africa.
http://img255.imageshack.us/i/dscf3596.jpg/
This shows the front pole in the box of wood:
http://img220.imageshack.us/i/dscf3598e.jpg/
This shows the front pole (side on), and where the radio had to be to test it - the coax cable was only long enough for there, so I had to sit half in between some bushes - some of which was Blackberry with thorns :(
http://img59.imageshack.us/i/dscf3608.jpg/
This shows it side on after it was all up:
http://img508.imageshack.us/i/dscf3612.jpg/
This is just before I pulled it down again. It was getting dark and a bit cold, so I decided to stop:
http://img521.imageshack.us/i/dscf3613d.jpg/
Todays results:
A funny story first. I had everything set and I turned on the receiver (which wouldn't go at first...a thing that can happen with frg-8800s when unplugged, and so I had to take a battery [used for keeping the memory of frequencies] out (which resets things), and tried the AM broadcast band. I thought "I wonder if this will now block out the bigger radio stations (that come from the North Island of NZ) and be stronger on the ones down south west?"
I turned the radio's tuning knob and there was hardly anything showing up. Even the big stations were weak and had noise.
I was excited, and thought "Wow, this antenna blocks rear signals better than I thought it could".
While I was pleased, it just didn't feel right...so I looked around and checked everything.....and all seemed fine....so I dis-connected the coaxial cable and there was no change in sound. I thought I must have damaged my radio when I accidentally pulled the power cord and pulled the radio a bit off of the little step ladder it was on. Then I looked, and saw that I had had the cable plugged into the wrong socket :)
The radio also has a socket for an antenna to listen to the vhf airband and I had plugged the ewe into that by mistake. The radio was in the garden and so I had had to plug the cable in while standing in front of it (i.e. instead of being behind the radio and plugging it in with the socket visibly in front of me).
I quickly changed it and the broadcast band was back to normal.
It did however still weaken rear signals like the other day, but now in reverse i.e. blocking north stations because I had now pointed the antenna south instead of north. Of course the northern stations were still there ( seeing as they are from New Zealand), and also because I think they are all rebroadcast anyway from a mountain in Dunedin where I live, so there wasn't really any way of blocking them :) ....even by plugging into the wrong socket.
Anyway, I had a quick tune around but it was afternoon, so no real chance of hearing any other countries' AM broadcast band stations. I tried later when it got darker, but not for long, but didn't hear anything really. There were a couple of things I wasn't sure about but they were probably NZ stations.
I'm not really an AM (called broadcast or MW band) person anyway (although when I get the ewe up properly I think I will enjoy trying it at night for other countries' normal local AM stations.
HF (shortwave)
I was really wanting to try hf, so I tuned around in the afternoon and I was getting loads of Spanish speaking shortwave broadcast stations. It was very sunny here (for any new radio people - the sun's position in the sky affects which radio waves get to you and which ones don't, from other countries)(I can't be sure of the time- I just know I was getting hot) and yet I was getting some great signals. I was even getting them around 6 mhz (and lower? ..I can't remember) ( normally during daytime, transmissions from overseas are on higher frequencies, and when night they go to lower frequencies). I don't listen a lot to shortwave broadcast stations, so I cannot say for sure if the antenna was responsible or not, but it seemed so much of a coincidence that most were Spanishy sounding and no ( or nearly no) strong noticable Asian stations (i.e. as I tuned, nothing jumped out strongly that was Asian..) Maybe I was telling myself that everything was Spanishy but I also got something that sounded possibly from the Caribbean, and some Middle Eastern/African sounding etc. I also possibly hearing European things too I think. It wasn't so much what I heard ( although that was convincing me that the antenna was really working superbly), but what I "didn't" hear. I wasn't noticing Asian stations.
When I tried tuning for utility stations ( aircraft etc. ) and amateur radio areas, again, I only heard Asian things a few times. The other day, nearly everything seemed Japanese. I came across various Atlantic civil aviation frequencies like Santa Maria and Gander. I didn't hear any Asian aviation freqs, although strangely I did have San Francisco coming in ok. I don't know what path the San Fransisco signal was taking to reach me. It could have come to the front of the antenna, but it might have simply been from the back. I suppose I shouldn't expect the antenna to be blocking out everything from behind it. I never used to expect that. Its just since the other day and the seemingly fantastic directionality I was getting, you then start to expect no rear signals at all :) (Well, not really expecting that, but you get a bit disappointed when you hear something from behind.)
Variable Resistor:
Throughout today, I went back and forth, adjusting the variable resistor value ( how much the knob is turned ), to see what would happen. Sometimes, not a lot happened, probably because the noise was from the same direction as the wanted signal.
Some stations however, you really noticed funny things happening.
I heard a utility station which sounded Spanishy, but I found that the signal strength increased when I turned the knob the "other" way (i.e. the way to have not so much blocking of rear signals).
I think the station might actually have been from the Phillipines or somewhee else in Asia, and thats why it was Spanish.
I know for certain though, after today's and the other day's testing, that the variable resistor really does work and really does weaken rear noise and signals/ and increase the signal from in front.
Replies to questions:
Concerning the vertical lengths, I haven't tried different lengths. I just chose what the Floyd Koontz article and the dxing.info article, suggested. I didn't want anything that would be too high, as it might get in the way of my neighbours views, and might worry people that it might fall down :)
Also, I am not sure about the phasing. (for anyone who is wondering - a phased antenna is like some tv antennas - it can have a big pole at the back and then a smaller one in front and others in front of that etc....and they each kind of catch the signal and bounce it around each pole in such a way that the pole with the wire connected to it, gets a strong signal from a certain direction - if you want to look at the technical specifics of this, try a search on the internet for a "yagi antenna" or yagi-uda).
I am not sure if it would or wouldn't work if one vertical wire/pole was shorter. ( I don't know enough about how the EWE really works to say - Calico, would you be able to take sections of your fishing rod off and so have one vertical shorter etc. Maybe you could test how different lengths work that way - by the way, were you using the rods as supports for wires or are the rods metal and acting as the vertical part of the antenna?)
I hadn't thought about that (2 different sized verticals). I had thought "What would happen if you put a smaller vertical in front of it - but not connected to anything - would it be like a director on a yagi?". I don't have room to try it though anyway :)
Ok, well I had better stop now.
db1 (David)
Last edited by db1 at Monday, 10-Jan-11 12:21:19 UTC
Here are some pictures of the bits and pieces I am using:
These are the alluminium poles:
http://img573.imageshack.us/i/dscf3582g.jpg/
Here they are again with the 7.5 metre wire attached by the hose clamps:
http://img31.imageshack.us/i/dscf3579t.jpg/
The next picture shows the bottoms of both poles, with the hose clamps on and with the wire that will go to the antenna wingnut of the un-un (I have this wire on already because the pole is going into the box of wood and it would be impossible to put it on once its in:
http://img691.imageshack.us/i/dscf3580a.jpg/
Here is the back end, in position, balanced/held up by wood and a wooden chair:
http://img340.imageshack.us/i/dscf3583h.jpg/
This shows the bottom of the rear pole, with a wire from it going to the variable resistor (or called potentiometer), and a wire from another connector of the variable resistor going to the hose clamp on the ground rod:
http://img337.imageshack.us/i/dscf3584o.jpg/
Note in the picture above I have two wires going to the rod. This is not required. I had to do this originally to allow me to have one wire to the ground rod and the other connected to another wire that ran along the ground (directly underneath the horizontal 7.5 metres wire) and joined up to the ground rod at the other pole. This wire was 7.5 metres too. This is the counterpoise I mentioned that I tried just in case the concrete was affecting things. I don't know if a counterpoise (if used) has to go straight to the other end or if it can go off at an angle and then come back to the other ground rod. I had originally thought I would need one because the original idea meant that one vertical would be coming down to concrete-not soil, so I thought I would need it, but I have since changed the plan and now both ends are above soil.
This next picture shows the wire from the Variable Resistor fastened to the ground rod by the hose clamp (the ground rod clamps are bigger than the others due to the rod being wider than the antenna poles.)
http://img402.imageshack.us/i/dscf3587c.jpg/
Here is a close up of the Variable resistor. The middle one doesn't have to go through that little hole by the way. I just did it that way. Also, it doesn't have to be soldered in this order. I was thinking afterwards I wanted to put the antenna wire on one of the end connectors of the variable resistor, but I had already done it this way and I looked it up to make sure this was ok and it supposedly is, so thats ok. It just depends what way you want to turn the variable resistor, to get higher blocking of signals coming from directions behind the rear of the antenna.
http://img600.imageshack.us/i/dscf3588v.jpg/
This shows the bottom of the rear pole:
http://img98.imageshack.us/i/dscf3589.jpg/
This is the "front end" of the antenna. The front pole goes into the box at the top of the picture, and a wire that is clamped to the bottom of this pole, pokes out of that little hole at the bottom (on the side) of the box. This wire then connects to the antenna wignut of the un-un, which is pictured on the piece of wood (with the coaxial cable connected, running back to the radio - which is stuck in between bushes :) )
http://img602.imageshack.us/i/dscf3590.jpg/
This shows the same:
http://img233.imageshack.us/i/dscf3591r.jpg/
Here is the rear pole after the front end has been put up too :
http://img714.imageshack.us/i/dscf3595s.jpg/
This is taken from behind the rear pole, showing the front pole (hard to see) in the distance. This also shows the direction it is pointing. You can see the water in the distance. Thats the Pacific Ocean, and after that its Antarctica and then between South America and South Africa.
http://img255.imageshack.us/i/dscf3596.jpg/
This shows the front pole in the box of wood:
http://img220.imageshack.us/i/dscf3598e.jpg/
This shows the front pole (side on), and where the radio had to be to test it - the coax cable was only long enough for there, so I had to sit half in between some bushes - some of which was Blackberry with thorns :(
http://img59.imageshack.us/i/dscf3608.jpg/
This shows it side on after it was all up:
http://img508.imageshack.us/i/dscf3612.jpg/
This is just before I pulled it down again. It was getting dark and a bit cold, so I decided to stop:
http://img521.imageshack.us/i/dscf3613d.jpg/
Todays results:
A funny story first. I had everything set and I turned on the receiver (which wouldn't go at first...a thing that can happen with frg-8800s when unplugged, and so I had to take a battery [used for keeping the memory of frequencies] out (which resets things), and tried the AM broadcast band. I thought "I wonder if this will now block out the bigger radio stations (that come from the North Island of NZ) and be stronger on the ones down south west?"
I turned the radio's tuning knob and there was hardly anything showing up. Even the big stations were weak and had noise.
I was excited, and thought "Wow, this antenna blocks rear signals better than I thought it could".
While I was pleased, it just didn't feel right...so I looked around and checked everything.....and all seemed fine....so I dis-connected the coaxial cable and there was no change in sound. I thought I must have damaged my radio when I accidentally pulled the power cord and pulled the radio a bit off of the little step ladder it was on. Then I looked, and saw that I had had the cable plugged into the wrong socket :)
The radio also has a socket for an antenna to listen to the vhf airband and I had plugged the ewe into that by mistake. The radio was in the garden and so I had had to plug the cable in while standing in front of it (i.e. instead of being behind the radio and plugging it in with the socket visibly in front of me).
I quickly changed it and the broadcast band was back to normal.
It did however still weaken rear signals like the other day, but now in reverse i.e. blocking north stations because I had now pointed the antenna south instead of north. Of course the northern stations were still there ( seeing as they are from New Zealand), and also because I think they are all rebroadcast anyway from a mountain in Dunedin where I live, so there wasn't really any way of blocking them :) ....even by plugging into the wrong socket.
Anyway, I had a quick tune around but it was afternoon, so no real chance of hearing any other countries' AM broadcast band stations. I tried later when it got darker, but not for long, but didn't hear anything really. There were a couple of things I wasn't sure about but they were probably NZ stations.
I'm not really an AM (called broadcast or MW band) person anyway (although when I get the ewe up properly I think I will enjoy trying it at night for other countries' normal local AM stations.
HF (shortwave)
I was really wanting to try hf, so I tuned around in the afternoon and I was getting loads of Spanish speaking shortwave broadcast stations. It was very sunny here (for any new radio people - the sun's position in the sky affects which radio waves get to you and which ones don't, from other countries)(I can't be sure of the time- I just know I was getting hot) and yet I was getting some great signals. I was even getting them around 6 mhz (and lower? ..I can't remember) ( normally during daytime, transmissions from overseas are on higher frequencies, and when night they go to lower frequencies). I don't listen a lot to shortwave broadcast stations, so I cannot say for sure if the antenna was responsible or not, but it seemed so much of a coincidence that most were Spanishy sounding and no ( or nearly no) strong noticable Asian stations (i.e. as I tuned, nothing jumped out strongly that was Asian..) Maybe I was telling myself that everything was Spanishy but I also got something that sounded possibly from the Caribbean, and some Middle Eastern/African sounding etc. I also possibly hearing European things too I think. It wasn't so much what I heard ( although that was convincing me that the antenna was really working superbly), but what I "didn't" hear. I wasn't noticing Asian stations.
When I tried tuning for utility stations ( aircraft etc. ) and amateur radio areas, again, I only heard Asian things a few times. The other day, nearly everything seemed Japanese. I came across various Atlantic civil aviation frequencies like Santa Maria and Gander. I didn't hear any Asian aviation freqs, although strangely I did have San Francisco coming in ok. I don't know what path the San Fransisco signal was taking to reach me. It could have come to the front of the antenna, but it might have simply been from the back. I suppose I shouldn't expect the antenna to be blocking out everything from behind it. I never used to expect that. Its just since the other day and the seemingly fantastic directionality I was getting, you then start to expect no rear signals at all :) (Well, not really expecting that, but you get a bit disappointed when you hear something from behind.)
Variable Resistor:
Throughout today, I went back and forth, adjusting the variable resistor value ( how much the knob is turned ), to see what would happen. Sometimes, not a lot happened, probably because the noise was from the same direction as the wanted signal.
Some stations however, you really noticed funny things happening.
I heard a utility station which sounded Spanishy, but I found that the signal strength increased when I turned the knob the "other" way (i.e. the way to have not so much blocking of rear signals).
I think the station might actually have been from the Phillipines or somewhee else in Asia, and thats why it was Spanish.
I know for certain though, after today's and the other day's testing, that the variable resistor really does work and really does weaken rear noise and signals/ and increase the signal from in front.
Replies to questions:
Concerning the vertical lengths, I haven't tried different lengths. I just chose what the Floyd Koontz article and the dxing.info article, suggested. I didn't want anything that would be too high, as it might get in the way of my neighbours views, and might worry people that it might fall down :)
Also, I am not sure about the phasing. (for anyone who is wondering - a phased antenna is like some tv antennas - it can have a big pole at the back and then a smaller one in front and others in front of that etc....and they each kind of catch the signal and bounce it around each pole in such a way that the pole with the wire connected to it, gets a strong signal from a certain direction - if you want to look at the technical specifics of this, try a search on the internet for a "yagi antenna" or yagi-uda).
I am not sure if it would or wouldn't work if one vertical wire/pole was shorter. ( I don't know enough about how the EWE really works to say - Calico, would you be able to take sections of your fishing rod off and so have one vertical shorter etc. Maybe you could test how different lengths work that way - by the way, were you using the rods as supports for wires or are the rods metal and acting as the vertical part of the antenna?)
I hadn't thought about that (2 different sized verticals). I had thought "What would happen if you put a smaller vertical in front of it - but not connected to anything - would it be like a director on a yagi?". I don't have room to try it though anyway :)
Ok, well I had better stop now.
db1 (David)
Last edited by db1 at Monday, 10-Jan-11 12:21:19 UTC
Message from Calico at Saturday, 15-Jan-11 17:05:59 GMT
Hi David,
Weekend is here already!
Left it for some time just in case anyone else wanted to comment, but after 7 days we last heard from you, we really wonder how it's going
Any progress ? Any good catches ? Maybe any tantalizing videos of anything RXed ?
Tried Ewe here, but didn't manage to get as good a null as with a pennant antenna I am using here.
If you want, I can send you a video of a station from Buffalo N.Y., about 5600 km away from my QTH that I received with the pennant ?
Keep us posted + 73 from your friends at GT !
Tim
Weekend is here already!
Left it for some time just in case anyone else wanted to comment, but after 7 days we last heard from you, we really wonder how it's going
Any progress ? Any good catches ? Maybe any tantalizing videos of anything RXed ?
Tried Ewe here, but didn't manage to get as good a null as with a pennant antenna I am using here.
If you want, I can send you a video of a station from Buffalo N.Y., about 5600 km away from my QTH that I received with the pennant ?
Keep us posted + 73 from your friends at GT !
Tim
Message from db1 at Sunday, 16-Jan-11 08:17:41 GMT
Hi Calico and others. Not sure if you saw the last post's update showing results of pointing the Ewe south instead of north, and pictures. Lots of other topics by people got posted that day on Gtuners and the post got pushed down the list, so you may not have seen it updated. You may have though. Anyway, I have been digging holes, and buying concrete and some pvc tubes, but no testing.
I have also been doing a lot of other work in the garden (non-radio related), so things are going slowly but soon I hope to pour the concrete around the pvc sleeves and then I think attach the vertical poles to wooden poles and have the wooden poles slot into the sleeve holes in the ground.
Once I pour the concrete it will take 28 days for it to fully cure, but after a day or two after pouring, it should probably be ok to try it out with guy ropes taking a lot of the strain.
I am also going to try hanging a full wire EWE next to the pole version, and test if any problems arise with performance. I will try them in opposite directions and if having them close does ruin things, I will take the full wire one down and attach some switches or relays (to the original EWE) to allow switching between north and south reception.
In reply to Calico,
Thats a pity the ewe didn't work too well, but thats good that your pennant is working well. Could you tell me if you used an un-un (or some form of transformer, and what it is) and coax., or if you used twin lead type wire of around 450 or something ohm?
I have never tried a pennant (I chose ewe for height and length reasons) but thats great it is giving you the nulling at your location.
I am going to put the test ewe out the side of my place too to see how it behaves there, as it only has a small strip of earth beside a driveway, and I am wanting to know if the ground rods would work as well in this place as they do in the back of the house where there is more ground and possibly has more moisture. I'll post results of that soon hopefully.
I will test if watering the area or adding things (like salt) to the soil might help results out there.
Unfortunately I don't think I can post videos of receiving sessions as the law here says we can listen to whatever we want to on radio but we can't re-transmit it etc. Can't remember if this only applies to utility stations or if we can upload recordings of civil aviation and broadcast stations etc.
Calico, thanks for offering your video. That would be great.
Do you want to send it to me via email or upload to youtube or something?
db1 (David)
Last edited by db1 at Sunday, 16-Jan-11 08:19:53 UTC
Last edited by db1 at Sunday, 16-Jan-11 08:29:29 UTC
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