Comments on KBC program schedule reception on 25 Nov 2012

I didn't want to clutter the schedule with my own comments, so I'll note them here.

Turns out tonight's broadcast was just a replay of last week's. I was surprised when it seemed like the song list was familiar and then the digital modes broadcast at 01:30 UTC was the exact same. I was expecting only two modes.

Consolation was that I had a second chance at a perfect copy of the MFSK64 schedule, and so it was. It's not legit HTML, though. I added p tags where there weren't any, closed off p tags elsewhere, and removed html/body tags at the beginning and end.

Also, the pre tag for the KBC logo was in between the beginning body and html tags.

I mentioned last week that forward error correction was good, but I don't actually know if the DominoEx 16 transmission used FEC or not. What I do know is that FEC plus frequency diversity is really good, because I was unable to receive PSK125R and DominoEx 16 error free yet again, but MFSK32 was perfect.

I don't really trust the fldigi reported SNR for frequency shift keying modes. MFSK32 and 64 were anywhere from -1 dB to +3 dB, and yet on the demod spectrum the frequency carrier to noise ratio was easily 20 dB. The PSKR modes were reporting 24 dB SNR, which is more reasonable, and yet that's not sufficient for error free reception, even though those modes use typical FEC things like convolutional codes and interleavers.

I typically use AGC when listening to anything non digital, and it can kind of mess up PSK type transmissions. So FSK has an advantage if decoding on the fly. Fortunately I remembered to record the DDC this time around so I could retry PSK with a constant gain. I was still unable to get a perfect copy. So yes, (greater) frequency diversity and FEC are a winning combination.

The Mighty KBC 9450 kHz, MFSK64 Program Schedule, 25 Nov 2012

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The Mighty KBC

Program Schedule

The Mighty 6095 - keeping shortwave alive on 6095

All times in UTC

Monday through Friday

09:00 - 11:00 : Transportradio Onderweg - Bob van Beeten

Saturday

09:00 - 11:00 : Coast To Coast Country - The Emperor Rosko

11:00 - 12:00 : It's Radio But Not As We Know It - Dave Mason

12:00 - 13:00 : Soundtrack of the Sixties - Paul Graham

13:00 - 14:00 : The Golden Age Of Rock n Roll - Dave Mason

14:00 - 16:00 : Rock & Roll Saturday - Mike Marwick

Sunday

09:00 - 11:00 : Trucker Radio - Stan Campbell & Tim Dennis

11:00 - 14:00 : The LA Connection - The Emperor Rosko

14:00 - 16:00 : Rock & Roll Rewind - Ron O'Quinn

UTC Sunday on 9450 kHz

00:00 - 02:00 : The Giant Jukebox - Eric van Willegen

The Mighty KBC 9450 kHz digital modes, 17 Nov 2012

First transmission at around 01:30 UTC, decoded using MFSK32.

The Mighty KBC - The Mighty KBC - The Mighty KBC

DIGITAL TEXT OVER ANALOG SHORTWAVE BROADCAST FROM THE MIGHTY KBC

This test of digital text via shortwave broadcast uses three modes simultaneously. 

Centered at 1000 Hz on your waterfall is PSKR125. At 1500 Hz is DominoEX 16. At 2000 Hz is MFSK32.

If you are recording this transmission, you can try to decode all three of the modes from your recording.

For next week's digital test, please go to http://www.w1hkj.com/download.html and download FLMSG. We will use FLSMSG in addition to FLDIGI.

Thanks to The Mighty KBC and Eric van Willegen for allowing us to experiment with these digital text modes.

Now back to The Giant Jukebox! ...

MFSK32 was the only mode that yielded perfect copy. Forward Error Correction is good.

For the first transmission I recorded with AMSS but when playing back the wav file directly in FLDIGI bandwidth ended up being only 1 kHz. I thought it was because the wav was recorded incorrectly. Playing back the wav in WinRadio and running it through VSC wasn't a problem though.

The second transmission had KBC in ASCII art followed by a schedule. That one was not a perfect copy due to fading, and I only recorded the upper sideband due to the above issues.

The Disco Palace DRM @ 17875 kHz, 4 Nov 2012

Interesting, no audio stream.

Figures.

At 20:30, off air.