Brian Lloyd wrote: > 1. Turn off your AGC and go with manual RF gain control. Most rigs > have enough dynamic range to be able to deal with W1AW's signal at > full gain without AGC so it would just be a really strong signal in > the passband. With AGC off W1AW would not reduce the gain for the > other stations you are trying to receive.
This is good advice in general, however W1AW is about S9+40 here, which makes it 50-60dB stronger than the psk31 signals surrounding it. Sound card dynamic range is a theoretical 96dB, but much less in practice. Probably closer to 70dB (optimistic). To properly decode psk31 you want a S/N ratio of over 10dB, so even switching off the AGC may not be enough due to sound card limitations. > 3. If you don't have a narrower filter, offset tune the radio so that > W1AW is off the edge of the filter. Fldigi provides rig control so if > you have set that up, you can offset tune the rig but fldigi will > still properly display the frequency in the waterfall and it will > properly log the center frequency for your PSK31 QSO. This is certainly doable, but due to the slope of the filters in most radios, you will end up cutting off most psk signals above 3581 kHz (or below 3582), so you can inspect slices of 1/3 of the psk subband. > I have three different rigs I use for PSK (and other digital modes) > and every one of them lets me work PSK in the presence of a strong > signal. It all depends on how strong :) 30-40dB difference is usually surmountable. 50-60dB gets a lot harder due to sound card limitations. -- All rights reversed.
