I should have been more clear in my comment. The QEX article shows that PSK31 is terrible under conditions that induce phase changes. The MFSK16 and Olivia did much better. Even RTTY worked well under those conditions.
PSK31 failed, bad copy even under good SNR, with 3 ms multipath and 10 Hz Doppler. It did not do well with 2 ms multipath and 1 Hz Doppler. Since Pactor uses PSK I wondered if it would similarly fail as shown by the PSK31 results. I suspect that it handles Doppler better through frequency tracking algorithms. Rud Merriam K5RUD ARES AEC Montgomery County, TX http://TheHamNetwork.net -----Original Message----- From: digitalradio@yahoogroups.com [mailto:[EMAIL PROTECTED] On Behalf Of Walt DuBose Sent: Thursday, October 25, 2007 9:38 PM To: digitalradio@yahoogroups.com Subject: Re: [digitalradio] RE: QEX Article on HF Digital Propagation Rud Merriam wrote: > After a comment off list from Demeter I checked the Pactor > specifications. It uses DBPSK or DQPSK. > > Why do the reports about Pactor indicate it is more robust than the > QEX article would indicate? > > > Rud Merriam K5RUD > ARES AEC Montgomery County, TX > http://TheHamNetwork.net > Rud, If you go back to the DCC presentation of KN6KB of a few years back on his new software modem...he measured the robustness of Pactor, MT63 and several other modes and Pactor wasn't that much more robust than MT63 at a -5 dB SNR. If I invested a $K Buck or so in Pactor III and WinLink, I'd claim it was the best thing since sliced bread...woudln't you? 73, Wa;t/K5YFW Announce your digital presence via our Interactive Sked Page at http://www.obriensweb.com/drsked/drsked.php Yahoo! Groups Links
