I've been using Digipan (the free PSK31 software program) for CW and
RTTY tuning for a while and it really work great. It even helps on
SSB. Here's how:
ON CW: Digipan displays the complete audio spectrum coming from your
receiver as a waterfall display. When you engage a CW filter and tune
to a spot in the band with noise and no signal you will see swath of
blue that shows you exactly what audio frequencies are in the passband.
Recent versions of Digipan let you place a marker (looks like a thin
red line) at any audio frequency. I put a marker at 600 hz (my
preferred side-tone frequency). CW signals appear like a dashed yellow
line. To get on frequency, you just tune until the yellow CW signal
lines up with the red marker. You are now dead-on frequency. I find
it much easier to do this visually than to match the CW tone with the
spot tone in my head.
There is the added benefit in that you can see just exactly where your
PBT control is placing the passband. For instance if you use a 250
hz filter you can center the passband on 600 hz exactly. If you cascade
first and second IF filters you can see exactly what the result
looks like. Also for the first time, I find I can use the manual notch.
It looks like a black snake that you move to cover up an interfering
signal. Its much easier to get on target visually than by ear.
ON RTTY: -- I put markers on the mark and space frequencies and center
the 500 hz filter on them. You tune the radio until the RTTY signal
lines up with the markers. This beats the display on my PK232 by far.
ON SIDEBAND: I have the INRAD 2.8 filters in both the 9mhz and 6 mhz
IF. With the waterfall display I can line them up perfectly for the
widest (best sounding) response.
Connecting the sound board to the radio was pretty easy with the OmniVI.
No isolation transformers, attenuators or the like were required. Just
audio cable between the sound card and the radio. For receive only, the
adjustment of the audio level was a snap. Things got a bit tricky
when adjusting levels so the VOX worked on transmit but not too bad.
The only warning is that once you get the sound board hooked up to the
radio there is seemingly no end to the software to check out...
MFSK16 is the latest WOW.
73, Henry, W6GZ
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