Saturday, November 17, 2012

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.

No comments:

Post a Comment