Hi Jeff Thanks for your advice which I will follow up - the reason for going for a USB sound card is that the system must be operated portable with a Laptop - but perhaps there is a way to use a PCI sound card on a Laptop.
While we use WSJT at present we have a new Mode under development for the mill-Hz bandwidth. In testing this new mode is acheiveing around 15 dB better than WSJT with 5 mHz binwidths and should get to 20 dB better with 1 mHz binwidths. It uses M-ary FSK like WSJT but does not need a reference tone for time or frequency locking on the basis that both soundcards are GPS locked. Timing errors are not an issue as the tone durations are 16 mins at 1 mHz binwidth. We use around 20,000 separate M-ary tones (cf 64 for WSJT), which is sufficient to send the first three characters of a call sign in Clark-Karn source encoded format - thus it requires only two tones to be sent to receve a full callsign. However at one mHz bandwidth this takes 16 minutes to send a single tone and thus an hour to send two callsigns. However, we have some shorter techniques for exchanging reports and RRR so a QSO can be comppleted in around 3 hours, hi. We can fit 20,000 tones spaced 1 mHz apart into just 20 Hz so there is not problem there. We have not yet added FEC which should allow a further improvement but we would like to resolve the sound card stablity issues first. 73 Rex VK7MO _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.