I have heard: All India Radio 1000-1100 15410kHz ch1:English ch2:Music
Just only information (Not confirmed): KTWR Guam 7500kHz (Thu. only) cancelled 11995kHz (Wed. only) frequency changed to 9910kHz (effective from Jan 15) 1026-1056 13800kHz (Sun. only) cancelled
Happy to see Voice of Nigeria using DRM mode C instead of the usual mode B to combat the selective fading and other problems. Even if it means their bit rate drops to 9.1 kbps (see table 5.2 "DRM system bit rates" page 21 https://www.drm.org/wp-content/uploads/2019/02/DRM-Handbook.pdf, bit rate also because MSC using 16-QAM and protection level=0). Also note their transmitter is ~110 Hz low, lol.
When HF broadcasters switch to using the xHE-AAC codec (like India uses for MW) they should get better audio quality using lower bit rates.
@jks , OK, I adjusted the GRFC transmitter location. I lazily posted the location listed on Short Wave Info. Voice of Nigeria is rock solid this morning. Had to make another video of the KiwiSDR decoding it. Excellent decode. A speculative thought about the transmitter being ~110Hz low, is that it gives the signal just a bit more clearance from China International Radio carrier @ 15125KHz, also broadcasting from NW Africa. Or maybe they are always just off. It has been that way since I've been listening. When the signal is weak, it has helped to narrow the bandpass to put that 15125KHz carrier outside of the DRM signal.
Finally decided to take a good look at the DRM plugin, as I've got temporary troubles with the Pi4 that performs my WSPR decodes, so my Kiwi now has a little while where it's not providing 6 or 7 WSPR streams.
I've got very clean decodes at 22.00 UTC tonight Jan 25th from Zurich of All India Radio on 7550, at 22.5 dB, Radio France DRM on 3965 decoded at ~9.5dB China National Radio on 6030 did not decode, but I'm picking it up as SNR of about 3, and barely visible on the waterfall. Radio Romania though listed as green in the schedule, was not seen or heard.
15325KHz Voice of Russia GRFC loud and clear at grid DN14lf. I was able to decode on all antennas. This video is testing the KiwiSDR using the BeagleBone AI in 4 channel mode. All 4 channels were in use during the test and 2 of them were decoding DRM. It worked but with difficulty and with a rising CPU temperature. But if only one DRM channel, it was very good and is still decoding at S5. Ron KA7U
Radio New Zealand Inernational on 9780KHz, February 4, 2020, 18:00 utc. The output audio seems low on this signal. Don't know if it the station or the KiwiSDR. I do notice that my attempts to increase the audio gain with the audio control made no difference in output. Maybe I need a new speaker. Ron KA7U
Note that in Jushin's tweet they are using the xHE-AAC codec on HF which I have not seen before. There seems to be an audio dropout problem on service channel 1. Not clear if this is a codec issue on the Kiwi or a problem with the programming audio. Channel 2 seems fine.
Update: after noting that they were running 9 KHz BW, I pulled the corners of the passband in a tad and got an SNR improvement. China Radio Int'l sits right on the top corner of the 10 KHz passband
Luis manuel alc?ntara periodista independiente recibe amenazas de la polic?a cubana de ser separado de sus 3 hijos opositores cubanos enfrentan escalada represiva periodista cubana critica duramente a diario oficialista gran ma 9 estado unidense en china por coronavirus jefe del pent?gono reafirma compromiso de estados unidos para resolver crisis en vena.
Using Google translate:
Luis manuel alcantara independent journalist receives threats from the Cuban police to be separated from his 3 Cuban opposition children face repressive escalation Cuban journalist criticizes harshly official journalist great ma 9 unidense state in china for coronavirus pentagon chief reaffirms united states commitment to resolve crisis in vein
China National Radio DRM confirmed in San Diego CA on 7360 kHz at 0645 UTC on Feb 11, 2020. Mode B, 10 kHz, long interleaver, 4QAM SDC, 16QAM MSC, Protect A=1 B=1, Services A=1 D=0. AAC @ 14.56 kbps. UEP 20.7%.
"Update: after noting that they were running 9 KHz BW, I pulled the corners of the passband in a tad and got an SNR improvement."
But does this actually help? I don't know the details of the DRM decoder implementation and how the displayed SNR is calculated. But I suspect the SNR is computed directly from the signal in the receive passband before it reaches the DRM decoder. So the apparent increase may not actually mean anything. Since the DRM decoder knows the signal mode and bandwidth, it knows which carriers are in use and it should simply ignore any noise or QRM on unused carrier frequencies.
Phil, isn't it really weird that no-one is using Mr. Walker's wonderful VMSK modulation on the shortwave or other bands these days? I wonder why that is?
Comments
All India Radio
1000-1100 15410kHz ch1:English ch2:Music
Just only information (Not confirmed):
KTWR Guam
7500kHz (Thu. only) cancelled
11995kHz (Wed. only) frequency changed to 9910kHz (effective from Jan 15) 1026-1056
13800kHz (Sun. only) cancelled
9655kHz 2200-0100 confirmed
Also intermittent brief snippets of audio heard on this SDR in Germany.
Choppy audio on this one in Australia, no signal in Germany.
In Dream, the station name is written in Chinese. Just out of curiosity, is it possible to show them on Kiwi DRM decoder interface too?
https://www.google.com/maps/place/50°29'21.0"N+137°07'58.0"E/@50.6583203,136.9088155,643m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d50.48917!4d137.13278
Ron
KA7U
Chinese is now displayed in the station name.
0130UTC- 9420kHz CNR ???? (=Voice of China)
NW of Komsomolsk-on-Amur. Use Bing satellite map option to avoid Google-fail.
https://google.co.jp/maps/@50.6527778,136.9183333,170m/data=!3m1!1e3
When HF broadcasters switch to using the xHE-AAC codec (like India uses for MW) they should get better audio quality using lower bit rates.
Attachments:
https://forum.kiwisdr.com/uploads/Uploader/28/5a64725275d40c8eabbe57313799dc.png
Ron
KA7U
Currently not broadcast (as well as AM).
I've got very clean decodes at 22.00 UTC tonight Jan 25th from Zurich of All India Radio on 7550, at 22.5 dB,
Radio France DRM on 3965 decoded at ~9.5dB
China National Radio on 6030 did not decode, but I'm picking it up as SNR of about 3, and barely visible on the waterfall.
Radio Romania though listed as green in the schedule, was not seen or heard.
China National Radio
Ron
KA7U
Russia DRM test (GRFC)
First appeared at this frequency
Ron
KA7U
Ron
KA7U
7345 kHz, 1700-0200 UTC
Note that in Jushin's tweet they are using the xHE-AAC codec on HF which I have not seen before. There seems to be an audio dropout problem on service channel 1. Not clear if this is a codec issue on the Kiwi or a problem with the programming audio. Channel 2 seems fine.
Update: after noting that they were running 9 KHz BW, I pulled the corners of the passband in a tad and got an SNR improvement. China Radio Int'l sits right on the top corner of the 10 KHz passband
the result was:
Luis manuel alc?ntara periodista independiente recibe amenazas de la polic?a cubana de ser separado de sus 3 hijos opositores cubanos enfrentan escalada represiva periodista cubana critica duramente a diario oficialista gran ma 9 estado unidense en china por coronavirus jefe del pent?gono reafirma compromiso de estados unidos para resolver crisis en vena.
Using Google translate:
Luis manuel alcantara independent journalist receives threats from the Cuban police to be separated from his 3 Cuban opposition children face repressive escalation Cuban journalist criticizes harshly official journalist great ma 9 unidense state in china for coronavirus pentagon chief reaffirms united states commitment to resolve crisis in vein
But does this actually help? I don't know the details of the DRM decoder implementation and how the displayed SNR is calculated. But I suspect the SNR is computed directly from the signal in the receive passband before it reaches the DRM decoder. So the apparent increase may not actually mean anything. Since the DRM decoder knows the signal mode and bandwidth, it knows which carriers are in use and it should simply ignore any noise or QRM on unused carrier frequencies.
Ron
KA7U
Nada here at 16:46 wrong MUF for my qth