DRM heavy childbirth 02 Mar 2021

[kris]

    Finally, after many months of digging around with the software and computer, for the first time today I was able to hear audio on the Digital Radio Mondial system. DreaM v.2.1.1 AAC libfaad2_drm.dll Win10 x64

1202 UTC 15105 DRM S9+20 R. Kuwait M Arabic news
https://i.imgur.com/ciS84nq.jpg?1[/img]]

  The system looked charming, it was supposed to be a cure for the ailments of short wave propagation.
The topic is probably so ungrateful that it was not on our forum. Years pass and the system keeps crawling in diapers. Few stations transmit short transmissions, dedicated receivers are expensive and not widely available. The latest DreaM ver 2.2.1 software needs the xHE-AAC audio codec, which is patent protected, making it unavailable for SWL. It was supposed to be nice and it's sad.
   Interesting study   Digital Radio: A Review of the Latest Standards - HDRadio, DAB, and DRM     
   https://youtu.be/QI4LAUjl3VE

[redhat]

This is why I am perfectly happy to watch DRM fall on its face.  Either open source both transmission and reception, or kill it.

+-RH

[~SIGINT~]

DRM can be a bear to catch and there are some stations out there to listen to. I was recently enjoying Brazil DRM Experimental and it sounded great. I have a post on the board if you search for it. DREAM documentation is vague at best but since the Brazil DRM signal was coming in extremely well for me for extended periods of time over several days it gave me a chance to experiment and tweak all of the DREAM setting to a point where I think it is the most effective. Let me know and I can share.

Radio Marti on 7345.0 kHz is a big player, unfortunately they use an incompatible audio codec that DREAM will not decode. You will get the ID but that is it.

Here are some successful decodes from logs.

23:43 UTC 2021-02-02
11910.0 kHz (tune 11905.0 kHz)
Brazil DRM Exper (Brazil DRM Experimental); 12.46 kbps EEP aac+ Mono
DRM Journaline (data) is working;
Signal level is hovering around -80 dBm;
transmission is aac+ mono (12.46 kbps) + MM (2.30 kbps);
02:00Z -100 dBm, decoder mildly breaking up;
03:30Z -106 dBm, decoder now breaking up most of the time and no audio
03:53Z -112 dBm

Other stations to watch for which I was able to decode are:

23:46 UTC 2021-02-01
5875.0 kHz DRM (tune 5870.0 kHz)
TDF Radio France with French programming
aac Mono (8.08 kbps) + MM (6.8 kbps);
00:00Z End of broadcast

13:25 UTC 2020-05-16
15110.0 kHz DRM (tune to 15105.0 kHz Digital)
KWT Radio Kuwait Digital
Briefly received station then it went off the air

15:17 UTC 2020-05-15
15750.0 kHz DRM
WINB (http://www.winb.com/)

[ChrisSmolinski]

This is why I am perfectly happy to watch DRM fall on its face.  Either open source both transmission and reception, or kill it.

+-RH

I'll take kill it 

[kris]

  Hi All   In previous attempts to not receive audio, I had doubts whether I had a good configuration and compatibility of the codec with the sender.
It turned out that a strong signal at S9 + 20 level, that is over -80dBm, is necessary for decoding.
In my case it is a rare case and short-lived despite the good antenna.
    Someone in the network boasted that in the Dream 2.2.1 version with the xHE codec it is easier to decode weaker signals. This version no longer requires the faad codec but supports this version as well. Unfortunately, you have to compile the xHE codec yourself to Dream, which I can't do.
Maybe more years will pass before this mod reaches the thatch.
     Good luck hunting for the "bear"!  It tastes good 
For those willing to tame DRM, here is the source base:
https://sourceforge.net/projects/drm/files/dream/2.2/
https://www.reddit.com/r/RTLSDR/comments/grp6m2/dream_v221_for_windows_with_xheaac_support/
>Win10 troubleshooting  https://sourceforge.net/p/drm/discussion/general/thread/89a7d6fc8f/?limit=25
https://sdrplayusers.net/forums/topic/installing-dream-2-2-on-windows-i-want-my-drm/

[~SIGINT~]

The general consensus with v2.2 is that a lot of people cannot get it working, myself including because I am not using Windows 10. I would have to re-compile the source code and I cannot be bother right now. I am using the tried and proven v2.1.1 svn808.

My experience has been:
  -98 dBm, good lock;
-100 dBm, intermittent, decoder mildly breaking up;
-106 dBm, decoder now breaking up most of the time and no audio;
-112 dBm, no longer decoding.

And from my testing, the best decoder settings are:
Frequency Interpolation = Linear
Time Interpolation = Linear
Time Sync Tracking = Guard Energy
Number of Iterations = 1
No ticks in any of the selection boxes. (The bandpass filter can at times help if there is heavy interference.)

Molson Canadian Eh!

[redhat]

Of course, signal measurements are rather meaningless without some SNR or noisefloor measuring.  S9 for me likely would not be enough due to my high suburban noise floor.  Likewise in a quiet rural setting s5 may be enough.

Not to be too snarky, but S9 is -73dbm.  Therefore S9+20 is -53dbm.

+-RH

[ChrisSmolinski]

Even in my fairly low noise floor rural environment, it takes a lot of signal to get DRM to decode. It's a lot of effort for little result.

[~SIGINT~]

In my 02 Feb 2021 test the noise floor was approx -120 dBm and the SNR on the the Brazil DRM Experimental broadcast was 36.4 dB. The SNR in the DREAM application was at 19.9 dB. It was coming in good and strong. The station does not appear to be broadcasting at this time or is no longer making it up this far North. I would have to check a WebSDR in that region of the world to see if it is still on the air.

[~SIGINT~]

For all interested, I have shared some screen shots of the Brazil DRM Experimental transmissions captured between 2 and 4 February 2021, including screen shots of the DRM NewsService Journaline service.

Enjoy

http://www.milspec.ca/radiodx/