[SADXA] Shifting FT8 signals for more sensitive reception

[Jim Wysocki]

In case you were wondering why everybody else was spotting that Yemeni 
station on 10.131 Mhz and I gave the spot here as 10.130, here's why.

Moving the VFO frequency down by 1 Khz moves the stations in the upper 
end of the crystal filter's bandwidth more into the center, more 
sensitive part, of the RX filter's response curve.

There was great difficulty in consistently copying 7O73T when he was at 
the lower end of the dial.  But the missed decodes became much less when 
his signals (in all 3 data streams) were moved more into the center of 
the curve.  I think that made the difference between getting the QSO and 
losing it.  Of course I moved my transmitted signal 1 Khz up as well to 
compensate for the dial shift.  Doing so makes a big difference in a fox 
and hound FT8 situation.

You might consider a similar action when faced with a weak FT8 signal 
under light QRM but moderate to heavy QSB conditions.

GL & 73,  Jim  W9FI