Digital Mode Activity

Here is info on a rare upcoming VHF SSTV station passed on to us by
Eric, KH6CQ.

“Russian cosmonauts on the International Space Station are expected to
activate Amateur Radio Slow Scan Television (SSTV) transmissions on
145.800 MHz FM on July 30 and 31 The SSTV experiment should be active on
Monday, July 30, 1600 – 1930 UTC, and Tuesday, July 31, 1325 – 1915
UTC, using the RS0ISS call sign.

SSTV images will be transmitted using the Kenwood TM-D710 transceiver in
the Russian ISS Service Module. The format is expected to be PD-120.
More information on SSTV from the ISS is on the AMSAT-UK website at,

https://amsat-uk.org/beginners/iss-sstv/”

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Amateurs on the Big Island have been experimenting with new HF digital
voice software.  Well maybe new to some of us.

Pascal Nelson (AC7N) passes on this information about the this new mode,
which in theory provides better a better S/N ratio than SSB.

“The best way to learn about the mode is to go to the website:
https://freedv.org

I started looking at FreeDV about 18 months ago, and have followed it
since. AH6GT and I have had several QSOs between Volcano and Kona. I
have been haunting the international DV calling frequencies on 40m, 20m,
17m, and 10m, but the propagation has been poor.

I’ll report as I get more experience with the new 700D mode. It has
been able to sustain QSO at -2 to -3 dB SNR. SSB requires around +7 dB
SNR to be usable. That means up to a 10dB improvement for the DV over
SSB. The bit rate for 700D is 700 b/s with FEC. Voice is quite robotic –
but fairly easy to understand with a little practice.”

If you are interested in experimenting with this new digital mode,
Pascal says he welcomes contacts via his ARRL email address.

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ARRL Pacific Section
Section Manager: Joseph Speroni, AH0A
ah0a@arrl.org