[TenTec] Can a scout send Psk31

[Stuart Rohre]

George,  Yes, IF you are careful about the following:
To do PSK 31, make sure RIT is off.
To minimize the frequency correction circuit, have the power reduced to say
5 or 10 watts.  That is plenty good for PSK communications.  We have copied
PSK that was no audible in band noise!

Put a fan blowing up over the heat sink, to further minimize the possibility
of frequency change during transmission.  Use SSB mode.  Since the Scout
automatically switches SSB sideband sense, make sure you are using 20m and
up for PSK.  The Scout only does LSB below 20m.

Check your audio levels in and out of the sound card.  Make sure your ALC
light is not coming on, ie that the transmitter is operating in a linear
range of SSB.

Use a modem transformer for input and another for output audio to isolate
the radio from the computer ground bus.

Do you receive PSK 31 OK on the Scout?  If so, then attention to the steps
above should facilitate the transmission of PSK.

One other issue, the Scout does employ some audio filtering of the mike
input to optimize voice performance.  Make sure with a scope, if you have
one, that the audio waveform is not compromised by viewing what is coming
out of the sound card and what is coming out of the audio preamp section of
the Scout.  Use a X10 scope probe so as to not perturb the circuit signals.

Usually, the inability to successfully transmit PSK 31 is a function of
trying to run too much power, or using too high an audio input to the sound
card, thus causing distortion, or having a ground loop between computer and
radio.

We built a simple two transformer PSK interface using modem transformers,
that works with a variety of rigs at our club station.   I would check and
make sure any transformer isolation you build does come close to the
impedances needed on the mike input side of the radio.  A 600 ohm
transformer will work ok on the audio receiver output, because that line is
suited to driving an external speaker.  BTW, you might try both front and
back audio outputs if you are having trouble receiving PSK.  Usually , level
setting for non distortion takes care of any problems.

GL,
Stuart
K5KVH