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PSK-31 MFSK Hell via AO-10



Peter

I wonder if you've tried MFSK or Hellschreiber via AO-10? I'm sure by now
you've found that PSK31 dosn't like doppler much hi. Hellschreiber ( Feld
Hell ) is much more tolerant to doppler... in fact I've used it with FO-20's
70cm downlink! When compared to other modes, it has the least impact on the
satellites power budget because of it's low duty cycle, about  23%. It's not
as sensitive as the other modes but if they won't print due to doppler, the
extra sensitivity won't help any Hi.

I recently experimented with MFSK vs PSK31 and I can tell you that neither
is very tolerant to doppler but MFSK16 can print substatially better at
times. I conducted my experiments by copying my own downlink using two
instances of G3PLX's PSK31 software one for TX the other for RX and did the
same for Nino's MFSK. This allows you to use the full duplex capability of
your soundcard allowing simultanious TX and RX via Satellite. It's great for
testing different power levels modes etc.

Peter Klein, (KD7MW) was one of the first to use these modes via Satellite
and his article in the AMSAT Journal explains things in more detail. You can
see the screenshots of my early Hellschreiber experiments via Satellite here
http://users.nais.com/~ab2cj/sathell.htm. I can e-mail you the PSK31 vs MFSK
snapshots if you'd like.

73, Tony
AB2CJ






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