Rich and group, I have read from the SCS website that there is still throughput with P2 and especially P3 when down to maybe as low as -16 db below noise. Others have claimed that Pactor 2 and 3 drastically drop off by the time you reach -5 db S/N such as KN6KB's RFfootprints powerpoint on comparing various digital modes.
Can you quantify what some throughputs might be at the low S/N ratios? There isn't any miracle modulation scheme with pactor 2 and 3 from what I can see. What they do is optimize many little things which gives them improved throughput. I question whether P3 is going to work a lot better than the wider Olivia under the most difficult conditions, although I hear the claim made that it does extremely well. But I am not sure of the actual throughput under real world conditions. The curious thing is that if it can not operate below 100 baud, there should be times of doppler, bit smearing, multipath, etc., that would make pactor modes completely unusable even though low baud rate modes would work quite well. 73, Rick, KV9U Rich Mulvey wrote: >What BW/tones were you using for the Olivia comparison? > >The thing about Pactor 1 is that it's adequate for relatively good >conditions, but is noticably worse than >Pactor 2 and 3 when things get marginal. Pactor 3 absolutely shines >under the absolute worst conditions, >when all of the sound card mode operators have given up and turned off >their rigs, complaining that the band >is dead. ;-) > >- Rich > > > > >
