The forum is read-only currently.

DRM Heard

24

Comments

  • edited January 2020
    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
  • China National Radio
    9655kHz 2200-0100 confirmed
  • edited January 2020


    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? :smile:
  • @arnie: Station name in Chinese (via UTF8) is in today's v1.375 release. Thanks for mentioning that.
    fractional_n
  • edited January 2020
    11860KHz GRFC 22:00-01:00 1234567 Music 100 34 RUS Komsomolsk Amur, digital radio Mondial. Received location grid DN14lf, near Weiser, Idaho.
    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

  • Thanks for multilingual support.
    Chinese is now displayed in the station name.

    0130UTC- 9420kHz CNR ???? (=Voice of China)
  • @Ron: Maybe here? Radio Rossi Popova SW transmitters #1,2 http://wikimapia.org/#lang=en&lat=50.657460&lon=136.908960&z=14&m=w
    NW of Komsomolsk-on-Amur. Use Bing satellite map option to avoid Google-fail.
  • jksjks
    edited January 2020
    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.

    image

    Attachments:
    http://forum.kiwisdr.com/uploads/Uploader/28/5a64725275d40c8eabbe57313799dc.png
    fractional_n
  • edited January 2020
    @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.



    Ron
    KA7U
  • Has anyone logged VOK on 3560
  • 3560kHz Voice of Korea DRM broadcasts were temporary.
    Currently not broadcast (as well as AM).
  • 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.
  • 05:05UTC 13810kHz & 13825kHz
    China National Radio
  • I really like the ease of using the DRM extension on the KiwiSDR!
    Ron
    KA7U

  • 0100UTC- 15325kHz
    Russia DRM test (GRFC)
    First appeared at this frequency
    KA7U
  • 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

    fractional_n
  • edited February 2020
    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

  • jksjks
    edited February 2020
    Radio Marti (VOA)
    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.



  • jksjks
    edited February 2020
    Update: Radio Marti service channel 1 audio seemed fine when I listened directly today.
  • Radio Marti (DRM) heard on 7345 khz 1750Z 8 Feb 2020
  • edited February 2020
    Marti DRM loud here in NY this afternoon

    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
    ka9q
  • I was just listening to R.Marti DRM and recorded a wav file. I then did speech to text here: https://speech-to-text-demo.ng.bluemix.net/

    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
  • 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.
  • edited February 2020
    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? :)
    ka9q
  • ha ha ha... :smile:
  • WINB DRM this morning on 15750KHz @ 16:40 UTC.


    Ron
    KA7U
  • Ron,

    Nada here at 16:46 wrong MUF for my qth
  • WINB heard in KP03QA, Finland today on 15750 kHz @ 15 UTC, a little bit cracking; English-Spanish religious programming.

Sign In or Register to comment.