I haven't switched yet. Have some problems getting WinRadio VSC to work, wherein it's mapping VSC to the name of the motherboard's sound card, and there are a ton of out of band spikes.
Dream 1.17 is the waterfall in the top level.
Friday, December 28, 2012
Dream 1.17 is out
For those who don't stalk the drmrx forums, or the Dream's SourceForge page, a new version of the Dream DRM receiver has been released.
I haven't switched yet. Have some problems getting WinRadio VSC to work, wherein it's mapping VSC to the name of the motherboard's sound card, and there are a ton of out of band spikes.
Dream 1.17 is the waterfall in the top level.
I haven't switched yet. Have some problems getting WinRadio VSC to work, wherein it's mapping VSC to the name of the motherboard's sound card, and there are a ton of out of band spikes.
Dream 1.17 is the waterfall in the top level.
The Disco Palace DRM @ 17875 kHz, 28 Dec 2012
Back after a day off yesterday.
This kind of frequency selective fading is something I haven't seen out of TDP in a while. It's much better than the usual fast, deep, flat fading that lasts for anywhere from 1 to 4 seconds, exceeding the interleaver's abilities.
Wednesday, December 26, 2012
BBC World Service DRM @ 5875 kHz, 26 Dec 2012
S9+30 and no splatter :O
That's Disco Palace style fading.
Tuesday, December 25, 2012
Monday, December 24, 2012
MT63 identifier tone
3583 kHz around 03:15 UTC. Note that there are even OFDM sidebands beyond the designated 500 Hz bandwidth.
According to fldigi's performance thus far, MT63-500 works down to about 4, 5 dB SNR, and is 100% decodeable at 8 dB and above. Pretty steep error rate curve.
At one point it appeared that a binary file was transmitted, which is not supported by fldigi, but probably requires IZ8BLY's program.
Voice of Nigeria DRM @ 15120 kHz, 24 Dec 2012
Wow.
I tuned in the last half hour of the broadcast. Had to run again and didn't record DDC for playback (not, you know, like I'd want to hear the audio quality), but the SNR plot speaks for itself.
I tuned in the last half hour of the broadcast. Had to run again and didn't record DDC for playback (not, you know, like I'd want to hear the audio quality), but the SNR plot speaks for itself.
Sunday, December 23, 2012
RRI DRM @ 9780 kHz, 23 Dec 2012
Amazingly, the broadcast sits in between the periodic interference spikes coming from the washing machine.
Some DRM waterfalls recorded by WebSDR
All from the University of Twente WebSDR. You may notice a pattern.
BBC World Service @ 3955 kHz from Woofferton:
BBC World Service @ 7355 kHz from Moosbrunn:
RRI @ 9450 kHz from Tiganesti:
RRI @ 9600 kHz from Galbeni:
RRI @ 9650 kHz from Galbeni:
RRI @ 9780 kHz from Tiganesti:
Problem?
BBC World Service @ 3955 kHz from Woofferton:
BBC World Service @ 7355 kHz from Moosbrunn:
RRI @ 9450 kHz from Tiganesti:
RRI @ 9600 kHz from Galbeni:
RRI @ 9650 kHz from Galbeni:
RRI @ 9780 kHz from Tiganesti:
Problem?
Saturday, December 22, 2012
I forgot to record KBC digital modes tonight
And I was also away from the radio, so no decode attempt.
DRM Mix @ 9755 kHz, 22 Dec 2012
Yeah, I got nothing. Not even station letters.
But I just wanted to point out that the transmitter cut out - this was the second time I saw it do so.
Meanwhile at the Twente WebSDR:
S9+40, and look at that RF splatter. It seems that any time an existing AM transmitter is modified to carry DRM, this happens. Anyway, too bad WebSDR doesn't do 10 kHz upper sideband.
But I just wanted to point out that the transmitter cut out - this was the second time I saw it do so.
Meanwhile at the Twente WebSDR:
S9+40, and look at that RF splatter. It seems that any time an existing AM transmitter is modified to carry DRM, this happens. Anyway, too bad WebSDR doesn't do 10 kHz upper sideband.
The Mighty KBC @ 21600 kHz, 22 Dec 2012
A series of 8 minute segments for the global broadcast. Started out averaging S9+20, with some fading. Also, there was some QRM.
20 minutes in, fell to S9+10
47 minutes in, S9+30, now there is some periodic switching interference (the horizontal lines) across the DDC spectrum.
And signing off on S9+10
20 minutes in, fell to S9+10
47 minutes in, S9+30, now there is some periodic switching interference (the horizontal lines) across the DDC spectrum.
And signing off on S9+10
Friday, December 21, 2012
Voice of Nigeria DRM @ 9690 kHz, 21 Dec 2012
Only for the first half hour, migrated to 15120 kHz at 19:00 UTC.
BBC World Service DRM @ 7355 kHz, 20 Dec 2012
At -115 dBm noise floor, the 7 MHz band avoids most of the electronically generated interference that occurs in the 5-6 MHz neighbourhood (-105 dBm). At the moment I was getting better SNR from a transmitter farther away.
That is until, the fridge kicks in, and then 7 and 11 MHz are completely obliterated. Replacing the fridge not being an option, I guess I'll need to find a place that nulls it out.
Wednesday, December 19, 2012
The Disco Palace DRM @ 17875 kHz, 18 Dec 2012
You know what the ridiculous part is? It's not that it's S9+40, it's that it will fade 30 dB in a split second and then come back up, as indicated by the blue strip in the middle of all that green and yellow. I guess atmospheric fading really does that kind of thing.
The sad thing is, SNR is limited to 25 dB because the transmitter is creating self-interference. Clearly not linear enough for OFDM.
RNZI DRM @ 9870 kHz, 18 Dec 2012
There has been absolutely nothing on 17675 kHz on 13730 kHz these days, and 11675 kHz is barely above noise. Yet 9870 kHz is usually strong, it's just that it starts at 3 am local time.
Pretty good SNR, fridge QRM notwithstanding. In the last half hour it faded below minimum SNR so I finally went to sleep.
Pretty good SNR, fridge QRM notwithstanding. In the last half hour it faded below minimum SNR so I finally went to sleep.
Random RRI DRM transmitter drops @ 7370 kHz, 18 Dec 2012
Happened today (the 19th) as well, but they ceased broadcast and restarted successfully. Always a couple dB short of decode, thanks to code puncturing.
Thursday, December 13, 2012
Sunday, December 9, 2012
Voice of Nigeria DRM @ 15120 kHz, 9 Dec 2012
Christmas special with choir and sermon. Microphone placement was terrible, audio levels were terrible, announcer mic conflicted with stage mics, compression was terrible, overall production values were terrible.
The only thing good about this was the propagation, and lack of interference from REE on 15110 kHz. Wonder if they've cut back their schedule.
Lastly, flutes. Too. Freaking. Loud. And out of tune. And just plain wrong at times.
RRI DRM @ 9780 kHz, 9 Dec 2012
In the last half hour I got sufficient SNR to decode a jazz program.
Ignore the SNR to the left of the drop - that was VoN, terrible as usual. In fact, I only noticed the presence of RRI when I vacated the 15 MHz band because to terribleness.
The music quality was pretty good with some frame loss, although I'm indifferent to the use of stereo at such low bitrates (20.96 kbps). I'm still of the opinion that about 17.5 kbps AAC+ Mono without code puncturing is the way to go.
Ignore the SNR to the left of the drop - that was VoN, terrible as usual. In fact, I only noticed the presence of RRI when I vacated the 15 MHz band because to terribleness.
The music quality was pretty good with some frame loss, although I'm indifferent to the use of stereo at such low bitrates (20.96 kbps). I'm still of the opinion that about 17.5 kbps AAC+ Mono without code puncturing is the way to go.
Saturday, December 8, 2012
Blindingly obvious discovery: VSC can be used outside of WinRadio GUI
I've been trying to follow The Might KBC ever since they began broadcasting across the pond on Sunday 00:00 UTC. I say trying because the last two transmissions have suffered heavy fading - just straight up attenuation that gets progressively worse until the carrier sits at around -80 dBm with a -110 dBm noise floor, and that's before any intermittent QRM raises it to -105 dBm. Audio typically peaks 30 dB below the carrier, so nothing was going to be heard other than white noise.
On the KBC Facebook page there was a link to WebSDR, and over there 9450 kHz was like, -33 dBm / S9+40. Awesome. My next problem was how to get the audio into fldigi for the digital mode segments of the program.
I tried the Stereo Mixer trick to no avail. My use of a USB headset may be a contributing factor. Instead, I ended up defaulting audio playback through the WinRadio Virtual Sound Card. Since it doubles as a recording device, I can then feed through the audio into the USB headset.
Grabbed Audacity to record the digital segments just in case I picked the wrong mode in fldigi and messed up the first several seconds of the broadcast.
On the KBC Facebook page there was a link to WebSDR, and over there 9450 kHz was like, -33 dBm / S9+40. Awesome. My next problem was how to get the audio into fldigi for the digital mode segments of the program.
I tried the Stereo Mixer trick to no avail. My use of a USB headset may be a contributing factor. Instead, I ended up defaulting audio playback through the WinRadio Virtual Sound Card. Since it doubles as a recording device, I can then feed through the audio into the USB headset.
Grabbed Audacity to record the digital segments just in case I picked the wrong mode in fldigi and messed up the first several seconds of the broadcast.
The Mighty KBC MT63-1000 @ 9450 kHz, 9 Dec 2012
THE MIGHTY KBC
Special broadcasts on 22, 23, 25, and 26 December
1500-1600 UTC
Europe: 9835 kHz
North America: 21600 kHz
Asia: 15470 kHz
1600-1700 UTC Europe: 9755 kHz DRM
Visit www.kbcradio.eu for more information.
Thanks for decoding this KBC text transmission. See you next week...
===
Bear in mind, I'm cheating by decoding this off of a WebSDR page in the Netherlands. That yielded 13 dB SNR and perfect copy.
The Mighty KBC MT63-1000 @ 9450 kHz, 9 Dec 2012
THE MIGHTY KBC
Special broadcasts on 22, 23, 25, and 26 December
1500-1600 UTC
Europe: 9835 kHz
North America: 21600 kHz
Asia: 15470 kHz
1600-1700 UTC
Europe: 9755 kHz DRM
The next text transmission, just before 0200 UTC, will be in the MT63-2000 mode, long interleave, centered at 1500 Hz.
===
Bear in mind, I'm cheating by decoding this off of a WebSDR page in the Netherlands. That yielded 13 dB SNR on MT63-1000 and perfect copies on both MT63 and PSK-125R.
BBC World Service DRM @ 5875 kHz, 8 Dec 2012
Even though 3955 kHz is still a QRM disaster (someone loves using their plasma TV at night), it was unusually strong, to the extent I could actually decode a couple seconds of audio here and there. It gave me hope that propagation would continue to be good once BBC migrated to 5875 kHz.
It started pretty well, with very little fading. Of course this wasn't going to last, but I had long runs of continuous audio and Journaline was working.
It took about an hour to successfully populate all of the headline content, probably because of MSC frame loss.
I was kind of hoping for full blown articles. At a data rate of 67.5 B/s, it doesn't seem like it's transmitting constantly, otherwise the Journaline stream could have delivered a lot more than just headlines.
I also got EPG schedule data out to a week, not that it'll dictate when I'm able to tune in. Going from 2-4 am isn't something I'm interested in doing every weekend.
It started pretty well, with very little fading. Of course this wasn't going to last, but I had long runs of continuous audio and Journaline was working.
It took about an hour to successfully populate all of the headline content, probably because of MSC frame loss.
I was kind of hoping for full blown articles. At a data rate of 67.5 B/s, it doesn't seem like it's transmitting constantly, otherwise the Journaline stream could have delivered a lot more than just headlines.
I also got EPG schedule data out to a week, not that it'll dictate when I'm able to tune in. Going from 2-4 am isn't something I'm interested in doing every weekend.
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