PSK-31 interface help needed for FT-817
Rick WA1RKT wrote:
I have a new Yaesu FT-817ND that I would like to use on PSK-31.
According to the manual, one should be able to just connect the radio
to the sound card without the need for any interface boxes such as the
Rigblaster or Nomic.
I have done this with my old Icom IC-735 and it worked pretty well up
to about 10 watts of output, so one would think I should be able to
get away with it running only 5 watts or less on the FT-817.
My question is, have any of you all done that with success?
As for connections, I must say that the FT-817ND manual is pretty bad
at explaining how to hook it up.
On page 38 the manual discusses SSB-based AFSK and shows the radio
connected to a TNC.
Then on page 39 under PSK-31, it says only to "Connect the FT-817ND to
your computer's sound card or interface" without going into any detail
on how to do tyat.
I can only assume that the connections for audio are the same as shown
on page 38, but they don't say that explicitly.
I had an 817, and ran the transmit and receive audio directly to the
sound jacks on my laptop with no issues after I got the levels set
correctly. It's possible you may have to pad the output to the rig a
bit depending on what sound card you have.
The big question is, how is the PTT connected? Does that operate off
of DCD or DTR on a serial port? If so, note that the voltage coming
out of a serial port's handshake lines can be as much as +/- 15 volts
and still be within the RS-232 spec. I find it hard to believe that
+/- 15 volts on the PTT pin of the radio is OK.
I made an optoisolator from an led and a phototransistor from Radio
Shack. The led went to DTR with a current limiting resistor, something
like 5K I think, and the phototransistor went to the PTT input and ground.
Then I set PSK mode to USB for the PSK entry on the menu, and it worked
fine.
Tom
K0TAR
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