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Message from norave at Tuesday, 03-Dec-13 04:06:56 GMT
Hi folks,
I recently got an active antenna without PSU or further information:
http://qrg.globaltuners.com/tmp/unid_ant.jpg
Have you ever seen this one and are able to provide information on power supply, frequency range or even name the type?
Greetings from Amsterdam
Sven
I recently got an active antenna without PSU or further information:
http://qrg.globaltuners.com/tmp/unid_ant.jpg
Have you ever seen this one and are able to provide information on power supply, frequency range or even name the type?
Greetings from Amsterdam
Sven
Message from Calico at Tuesday, 10-Dec-13 12:50:37 GMT
Hi Sven,
Could easily be an H.F. antenna, with electronics encapsulated in the sleeve.
We couldn't seen the connector in the photo but chances are it works with some sort of DC injector and that the antenna is wideband.
You might still be able to get a rough indication with an analyzer, e.g. MFJ 259.
73 and Good Xmas,
Tim
Could easily be an H.F. antenna, with electronics encapsulated in the sleeve.
We couldn't seen the connector in the photo but chances are it works with some sort of DC injector and that the antenna is wideband.
You might still be able to get a rough indication with an analyzer, e.g. MFJ 259.
73 and Good Xmas,
Tim
Message from norave at Tuesday, 10-Dec-13 18:45:52 GMT
Hi Tim,
nice to see one of the rare people! I was able to power it up and it does raise the noise by several dB between about 10 and 170 MHz. On HF, however, a lot of interference is reducing the fun. Seems like these plasma TV's became pretty popular in my vicinity. I've had this antenna connected to the Amsterdam node for a couple of days and I was not really satisfied.
73 and I hope to see you b4 xmas,
Sven
nice to see one of the rare people! I was able to power it up and it does raise the noise by several dB between about 10 and 170 MHz. On HF, however, a lot of interference is reducing the fun. Seems like these plasma TV's became pretty popular in my vicinity. I've had this antenna connected to the Amsterdam node for a couple of days and I was not really satisfied.
73 and I hope to see you b4 xmas,
Sven
Message from Calico at Thursday, 12-Dec-13 00:44:20 GMT
Hey Sven,
Nice to catch up mate - hope all is good in the Nether-Lands! :)
Was having a look again at the antenna, and the screws at the bottom. These could have probably supported the counterpoise part of a groundplane system, especially if there is a 3rd screw at the back of the antenna, not visible in the photo.
Given the size of the antenna compared to the reference cigarette packet, it looks like the length of a VHF transmit/receive antenna. Marine? Aviation?
If you can/have the opportunity to remove the black weather proofing cap and get an idea of the vertical element's lenght inside (or at least measure the white sleeve's length), then you can use metal hanger wire of the same length ish and attach them to the bottom screws to do a radio test, even on FM band for a quick confirm?
Or if there are any spare telescopic whips from old radios hand,the telescopic radials can be set longer or shorter till the design frequency is approximated?
With some luck you may even get it to respond to Aviation frequencies.
Also, wonder what the feeding point of the antenna looks like. If it is N-type chances are it's at least VHF if not higher.
Interested in the results, hope you'll get it to work! :)
73 es gd dx
Tim
Nice to catch up mate - hope all is good in the Nether-Lands! :)
Was having a look again at the antenna, and the screws at the bottom. These could have probably supported the counterpoise part of a groundplane system, especially if there is a 3rd screw at the back of the antenna, not visible in the photo.
Given the size of the antenna compared to the reference cigarette packet, it looks like the length of a VHF transmit/receive antenna. Marine? Aviation?
If you can/have the opportunity to remove the black weather proofing cap and get an idea of the vertical element's lenght inside (or at least measure the white sleeve's length), then you can use metal hanger wire of the same length ish and attach them to the bottom screws to do a radio test, even on FM band for a quick confirm?
Or if there are any spare telescopic whips from old radios hand,the telescopic radials can be set longer or shorter till the design frequency is approximated?
With some luck you may even get it to respond to Aviation frequencies.
Also, wonder what the feeding point of the antenna looks like. If it is N-type chances are it's at least VHF if not higher.
Interested in the results, hope you'll get it to work! :)
73 es gd dx
Tim
Message from ku4a at Thursday, 12-Dec-13 13:32:50 GMT
Cal!!!!
Message from norave at Saturday, 14-Dec-13 13:51:14 GMT
Hey Tim,
it's definitely an active antenna, not for tx. Removing the black cap was the very first thing I have done. Unfortunately my cam was unable to take a decent picture, but I felt like looking into a big rubber duck antenna, with a small pcb covered in plastic. Although this was shrinked over the pcb, the silhouette of at least one transistor was visible. So, using an antenna analyzer would not make sense.
4m is not very popular over here, so I can't tell how the antenna performs on this band. However, there is a lot of QRM by broadcasters when scanning 108-118 MHz. Further, up to around 170 MHz it's doing a fine job. Despite the length of the antenna, it is performing equally compared to my X50 on 2m. On 70cm the active antenna is really deaf.
Adding radials to the antenna does not change a bit. I am, however, thinking of extending the passive part of the active antenna by adding some wire.
That's gonna be something for the next weekend or Xmas.
73 from Amsterdam
Sven
it's definitely an active antenna, not for tx. Removing the black cap was the very first thing I have done. Unfortunately my cam was unable to take a decent picture, but I felt like looking into a big rubber duck antenna, with a small pcb covered in plastic. Although this was shrinked over the pcb, the silhouette of at least one transistor was visible. So, using an antenna analyzer would not make sense.
4m is not very popular over here, so I can't tell how the antenna performs on this band. However, there is a lot of QRM by broadcasters when scanning 108-118 MHz. Further, up to around 170 MHz it's doing a fine job. Despite the length of the antenna, it is performing equally compared to my X50 on 2m. On 70cm the active antenna is really deaf.
Adding radials to the antenna does not change a bit. I am, however, thinking of extending the passive part of the active antenna by adding some wire.
That's gonna be something for the next weekend or Xmas.
73 from Amsterdam
Sven
Message from Calico at Monday, 16-Dec-13 00:32:36 GMT
KU !
Happy Christmas to you and yours! :)
73 + VAT unless it's discounted for Xmas :P
Happy Christmas to you and yours! :)
73 + VAT unless it's discounted for Xmas :P
Message from Calico at Monday, 16-Dec-13 01:34:04 GMT
Hi Sven - roger your new mail.
That's some interesting new information about what the antenna looks like from the inside the sleeve, as you say there appears to be an amplifier then.
Don't know what the connector(s?) look like from undernteath, this is important as if there is a separate DC supply line (bias tee) from the signal line there are implications about whether an can be analyzer used.
OK about radials attempt not having made any difference yet,though I know of quite a few of active VHF antennas that they rely on what's underneath them for the return signal path.
Encouraging that such a short antenna with no groundplane/radials can perform as well as a 1.7 m long X50, especially if the little one is not been used in an active configuration.
Wonder why there are more than one screw though at the antenna base- there seems to be some discoloration at the front one, which is what made me think there was something attached there, either a radial system if discoloration in all three screw points, or if in only one point then may have been the mast attachment. Still the function of the two other screws remains to be investigated in that case :)
Looks like a professional antenna to me.
And if it peforms fine up to 170 M/c, it would ring AIS bells to me, which would explain why it responds to freqs around 140 M/c. Also if it's an AIS (type) antenna, I would expect AC+DC to be fed with only one connector and only one cable.
Greetings to beautiful Amster-dam, which according to Uncle-Google:
"The name "Amsterdam" derives from the name of the Amstel river the
city was build on and from the word "dam", which means the same as in
English."
73,
Tim
That's some interesting new information about what the antenna looks like from the inside the sleeve, as you say there appears to be an amplifier then.
Don't know what the connector(s?) look like from undernteath, this is important as if there is a separate DC supply line (bias tee) from the signal line there are implications about whether an can be analyzer used.
OK about radials attempt not having made any difference yet,though I know of quite a few of active VHF antennas that they rely on what's underneath them for the return signal path.
Encouraging that such a short antenna with no groundplane/radials can perform as well as a 1.7 m long X50, especially if the little one is not been used in an active configuration.
Wonder why there are more than one screw though at the antenna base- there seems to be some discoloration at the front one, which is what made me think there was something attached there, either a radial system if discoloration in all three screw points, or if in only one point then may have been the mast attachment. Still the function of the two other screws remains to be investigated in that case :)
Looks like a professional antenna to me.
And if it peforms fine up to 170 M/c, it would ring AIS bells to me, which would explain why it responds to freqs around 140 M/c. Also if it's an AIS (type) antenna, I would expect AC+DC to be fed with only one connector and only one cable.
Greetings to beautiful Amster-dam, which according to Uncle-Google:
"The name "Amsterdam" derives from the name of the Amstel river the
city was build on and from the word "dam", which means the same as in
English."
73,
Tim
Message from norave at Monday, 16-Dec-13 06:52:52 GMT
Hi Tim,
as said some days ago I was able to power it up using a bias tee to pump 5V into it. Without knowing the exact specs I don't dare to raise the voltage. ;) The only connector on the antennas bottom is a PL connector.
You wrote:
"Encouraging that such a short antenna with no groundplane/radials can perform as well as a 1.7 m long X50, especially if the little one is not been used in an active configuration."
Nah, if it's not powered up, it's even worse than the rubber-duckie my Hong Kong HT came with. Since there is no effect if I am adding radials, I assume these three screws are just used to mount the antenna on top of a mast.
Gonna look more into it on friday evening.
73
Sven
as said some days ago I was able to power it up using a bias tee to pump 5V into it. Without knowing the exact specs I don't dare to raise the voltage. ;) The only connector on the antennas bottom is a PL connector.
You wrote:
"Encouraging that such a short antenna with no groundplane/radials can perform as well as a 1.7 m long X50, especially if the little one is not been used in an active configuration."
Nah, if it's not powered up, it's even worse than the rubber-duckie my Hong Kong HT came with. Since there is no effect if I am adding radials, I assume these three screws are just used to mount the antenna on top of a mast.
Gonna look more into it on friday evening.
73
Sven
Message from robnonstop at Thursday, 03-Apr-14 07:43:42 GMT
Hi all,
The antenna is definetily an active antenna. I have one too. It shoulc be able to receive signals from 100 khz to 150 Mhz. As all active antennas it is not brilliant in it's performance. When you don't have enough space to put up a full length logwire then you could try a loopantenna.
The voltage to power it up is 12V by the way. 200 mA.
The antenna is definetily an active antenna. I have one too. It shoulc be able to receive signals from 100 khz to 150 Mhz. As all active antennas it is not brilliant in it's performance. When you don't have enough space to put up a full length logwire then you could try a loopantenna.
The voltage to power it up is 12V by the way. 200 mA.
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