[Elecraft] K3 PSK31 with Digipan

Kok Chen chen at mac.com
Fri Sep 19 18:15:54 EDT 2008


On Sep 19, 2008, at 2:32 PM, Bob Cunnings wrote:
> Yes transmit is restricted - to the 2.7 (or 2.8) kHz filter. Hence the
> request to allow transmit using the 6 KHz filter, at least to same
> extent as receive (up to 4KHz currently).

We all agree that you can receive in a wide passband (even as wide as  
the 192 kHz that an LP-PAN provides).

For transmit, as long as the emission passband is not too wide to fit  
the rig's transmit passband, modify the software to note the receive  
offset that you have clicked in the waterfall and use CAT to apply the  
offset as XIT (or switch between A/B VFO) when transmitting.

I.e., you can send an absolutely fixed AFSK tone (tones, in the case  
of <m>FSK) from software and move the transmitted signal around in the  
RF spectrum by using XIT (or A/B VFO).  It should be a very simple  
change to whatever software that you are using (if you have the  
sources to the program, that is), as long as the program has access to  
the rig's CAT.

The advantage of doing it this way is that it has no dependency at all  
on how flat the rig's transmit audio passband is, since you are  
transmitting with the same fixed tone no matter where in the waterfall  
you have clicked.

You can also use the built in FSK/PSK generators in modern rigs to  
modulate your rig.  As long as you know what the tone/tone-pair it  
uses is, you can apply XIT to move it to where the received signal is  
in the waterfall.

73
Chen, W7AY



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