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Message from nickstr1 at Thursday, 31-Dec-09 10:49:24 GMT
This is a method I have found for decoding DRM on these two receivers WITHOUT a down mixer! Simply set the mode to LSB and the IF bandwidth to 50 KHz. Then offset the radio's tuning 12 KHz above the transmitter frequency and you will be able to receive DRM with it. The technique described does work with the Global Tuners receivers but you must have either two sound cards or two computers for best results.
Message from Robotix at Monday, 11-Jan-10 19:43:29 GMT
Is possible with PCR-2500 ?
Message from nickstr1 at Monday, 11-Jan-10 22:00:16 GMT
It might be but I am not sure about the receiver. The problem with some Icom receivers in this aspect is that they have an audio cut off filter which is designed to prevent heterodynes on AM shortwave broadcasts that cuts off the audio at 5 KHz. It is a major problem for DRM and means you have to modify the receiver (the Icom IC-R75 has such a filter) but also is a nuisance if you want better quality audio and these tuners because of having wide IF bandwidths available for AM are capable of it so it just depends on whether the receiver has this AF cutoff filter or not.
Message from Calico at Tuesday, 12-Jan-10 01:19:16 GMT
Hi there,
Before I physically modified a PCR 1000 to get a 12 kHz I.F. output for true DRM, I was able to decode DRM with only one sound-card, I did not need two, since what we get in this way is only Audio Frequency, not I.F. (Intermediate Frequency).
Since Robotix has a PCR- 2500, he can decode DRM with one audio card: Icom PCR-2500 Speaker Out + good quality Cable + \\\"Line In\\\" of Sound-card.
The decoding would last from a few seconds to a few minutes (IF LUCKY!) depending on strength, fading, splatter from left and right etc. Software used, was DREAM Version 1.6.1.
The ofset frequency that worked best for me was Station\\\'s nominal frequency + 10 kHz.
(12 kHz, is the I.F. output needed for sound card to digitize the analogue stream for DREAM program to process and decode)
The same \\\"sort of\\\" results were achieved with my PCR-1500, and although I don\\\'t have a PCR-2500, I cannot see why one wouldn\\\'t have the same results for that too, as the PCR-2500 has the same HF circuitry. Its HF is the same as the PCR-1500, same ceramic filters, same roofing filter, same specifications really if you look them up. PCR-2500 has a second VHF / UHF receiver, but only one HF receiver.
The methodology to \\\"receive\\\" DRM is described in detail at:
http://w2dtc.com/w2dtc-drm-page.htm
The right way to receive non-stop DRM is opening up the PCR and getting an IF output straight from the board, convert it to 12kHz. You can then choose to use this IF to feed either an SDR or DRM decoder (e.g. Dream).
Still because the phase noise of the PCRs is a bit on the high-end, DRM won\\\'t be as good as a low phase radio like AOR 7030, Perseus, etc.
Any cable (wires) connecting any radio to any sound-card introduce even more noise, which is one big problem with SNR. The solution to this is using VACs as much as possible, then Dx DRM is no problem, we used to receive on Dorset-DRM DRM stations from Peru to India every day.
73
Tim (Dorset Radio)
PS:
I forgot to mention, there are already DRM commercially made radios with an external antenna connection as well as telescopic whip for DRM on LW/MW/SW, FM with RDS, message screen etc, like the Di-Wave.
More at:
http://www.uniwave.fr/index.php?rubrique23&lang=en
Users\' Manual at:
http://www.uniwave.fr/download/DRM-2472%20IB%20UNIW%20001%20REV0%20-%20GB.pdf
Last edited by Calico at Tuesday, 12-Jan-10 01:44:37 UTC
Before I physically modified a PCR 1000 to get a 12 kHz I.F. output for true DRM, I was able to decode DRM with only one sound-card, I did not need two, since what we get in this way is only Audio Frequency, not I.F. (Intermediate Frequency).
Since Robotix has a PCR- 2500, he can decode DRM with one audio card: Icom PCR-2500 Speaker Out + good quality Cable + \\\"Line In\\\" of Sound-card.
The decoding would last from a few seconds to a few minutes (IF LUCKY!) depending on strength, fading, splatter from left and right etc. Software used, was DREAM Version 1.6.1.
The ofset frequency that worked best for me was Station\\\'s nominal frequency + 10 kHz.
(12 kHz, is the I.F. output needed for sound card to digitize the analogue stream for DREAM program to process and decode)
The same \\\"sort of\\\" results were achieved with my PCR-1500, and although I don\\\'t have a PCR-2500, I cannot see why one wouldn\\\'t have the same results for that too, as the PCR-2500 has the same HF circuitry. Its HF is the same as the PCR-1500, same ceramic filters, same roofing filter, same specifications really if you look them up. PCR-2500 has a second VHF / UHF receiver, but only one HF receiver.
The methodology to \\\"receive\\\" DRM is described in detail at:
http://w2dtc.com/w2dtc-drm-page.htm
The right way to receive non-stop DRM is opening up the PCR and getting an IF output straight from the board, convert it to 12kHz. You can then choose to use this IF to feed either an SDR or DRM decoder (e.g. Dream).
Still because the phase noise of the PCRs is a bit on the high-end, DRM won\\\'t be as good as a low phase radio like AOR 7030, Perseus, etc.
Any cable (wires) connecting any radio to any sound-card introduce even more noise, which is one big problem with SNR. The solution to this is using VACs as much as possible, then Dx DRM is no problem, we used to receive on Dorset-DRM DRM stations from Peru to India every day.
73
Tim (Dorset Radio)
PS:
I forgot to mention, there are already DRM commercially made radios with an external antenna connection as well as telescopic whip for DRM on LW/MW/SW, FM with RDS, message screen etc, like the Di-Wave.
More at:
http://www.uniwave.fr/index.php?rubrique23&lang=en
Users\' Manual at:
http://www.uniwave.fr/download/DRM-2472%20IB%20UNIW%20001%20REV0%20-%20GB.pdf
Last edited by Calico at Tuesday, 12-Jan-10 01:44:37 UTC
Message from Robotix at Tuesday, 12-Jan-10 21:15:40 GMT
Tanks de IK2RJI (Robotix)
Message from Calico at Wednesday, 13-Jan-10 11:59:13 GMT
You\'re very welcome Robotix :)
If you may be interested, I can modify your PCR-2500 for DRM, add a down-converter to get direct 12 kHz out @ 10kHz with a 3.5mm socket at the back of your radio. It will cost you a little bit, of course.
Or if you feel nervous about it, there is a ready solution, brand new radio with IF output for DRM at about 75 Euro including shipping (postage).
73
Tim
If you may be interested, I can modify your PCR-2500 for DRM, add a down-converter to get direct 12 kHz out @ 10kHz with a 3.5mm socket at the back of your radio. It will cost you a little bit, of course.
Or if you feel nervous about it, there is a ready solution, brand new radio with IF output for DRM at about 75 Euro including shipping (postage).
73
Tim
Message from vitesse at Sunday, 28-Mar-10 18:04:00 GMT
I've tried The unmodded trick with my PCR-1000 HF node. This is working well with the RCI (Radio-Canada International) from sackville.
Using the flash mp3 stream to decode it degrade seriously the SNR and the ability to decode it. Will try to add a direct feed from the DRM decoded signal on the node. Still have heavy problem with Virtual Audio Cable so more work need to be done.
Edit: Also Tried TDP Radio from their Bonaire transmitter at 15755khz and signal is rock solid. Now put a temporary stream on the receiver page
Last edited by vitesse at Sunday, 28-Mar-10 19:15:34 UTC
Using the flash mp3 stream to decode it degrade seriously the SNR and the ability to decode it. Will try to add a direct feed from the DRM decoded signal on the node. Still have heavy problem with Virtual Audio Cable so more work need to be done.
Edit: Also Tried TDP Radio from their Bonaire transmitter at 15755khz and signal is rock solid. Now put a temporary stream on the receiver page
Last edited by vitesse at Sunday, 28-Mar-10 19:15:34 UTC
Message from Calico at Friday, 04-Mar-11 13:22:45 GMT
DRM+ tests are taking part in the UK at the moment, in the Edinburgh area!
Frequency: 107 MHz
DRM+ is an alternative technology to DAB but it uses lower frequencies than DAB.
(1) http://tech.ebu.ch/docs/events/radiosummit11/presentations/ebu_radiosummit11_cornell.pdf (!)
(2) http://radiomagonline.com/digital_radio/ebu-notes-uk-drm-0302/
Frequency: 107 MHz
DRM+ is an alternative technology to DAB but it uses lower frequencies than DAB.
(1) http://tech.ebu.ch/docs/events/radiosummit11/presentations/ebu_radiosummit11_cornell.pdf (!)
(2) http://radiomagonline.com/digital_radio/ebu-notes-uk-drm-0302/
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