[Elecraft] K2 Filters - RTTY Mode PSK31...Problem...

[Wolf-Ruediger Juergens]

A.K.Forrest wrote:
> I think this is the major problem for PSK use. The clean local
> oscillator is great for preventing signals mixing up but the
> filtering is definitely not optimum. If someone knows a way around
> this I would also be very interested in the solution

Here is how I avoid this problem. I setup all the rtty filters with a
noise-gen for best passband at 1250Hz center frequency. Of course  the
center frequency is thereafter different for the filters. Now comes the
fine-rit into the game. I switch to, let's  say FL4 (200hz here) and
activate the fine rit. Now tune to a strong station (AGC off!) and
toggle between FL1 and FL4 while adjust the fine rit until no more
difference between the the wide and the narrow filter is visible. This
works best if you lock the audio frequency in your PSK program ,
somtimes it's called Net On/Off. The disadvantage is that you can't tune
with point and click anymore. I tune to a station with FL1 on with the
dial and then switch to FL4.

72 Wolf, DL2WRJ
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