|Carefully strip back about 4 inches of the outer insulation
on the white radio cable.
Using a sharp ended 'device'
starting at the cut end, un-weave the shield down to the
insulation. Pull the wires away from the shield and twist
the shield together to make one wire. Cut the shield wire
to be about 1/2 inch long and completely tin the remaining
Also cut the solid white wire to be about 1 inch long and
strip 1/4 inch and tin.
| The other end of this cable goes to the
connectors for your radio. Because every radio has a different
connector, I can't be of much help in this document. But
the general instructions would be:
- The white/blue wire goes to the radio audio out or
- The white/orange wire goes to the radio audio in or
microphone. Remember the pot should be set in the
center to start and then tuned for best transmission.
- The solid white wire goes to the radio's PTT.
- Then the shield goes to the radio ground.
This completes the interface and you should be able to do
some basic testing.
While testing is very subjective, I suggest you do the
- Fire up the computer and bring up Digipan -- You should
have loaded the software when you built the serial cable.
- Plug the orange cable into the computer's line-in or
- Plug the radio cable into your radio.
- Tune the radio to 14.070 MHZ and you should see some
activity on the water falls on Digipan. With no audio it
will be dark blue but audio/noise will cause it to turn
yellow or red. If you see red or yellow vertical lines
that look like train tracks that's great, as its a PSK31
signal. Move the mouse and clicking on the train tracks
should give you the text of the QSO. You might have to
use your computer's control panel to adjust the soundcard
volume level for the microphone or line-in for best levels,
- If you don't see any activity on the water falls, look
for something wrong with the audio lines. This is the very
top of the schematic and only involves the soundcard line in
cable, transformer T1 and the audio in from the radio.
- Now that you have the receive working, let's test the
- Plug in the serial cable at your computer. Click
on the CQ button at the top and the LED should light and
your radio should start transmitting. It will transmit
a short while and then stop when the CQ's stop. If
this works, then great. If not, we tested the serial cable
and opto isolator and LED in the test of the serial port
cable. So all that's left is the radio PTT. If all
checks out okay but still doesn't work, check to see if you
have a positive voltage on the PTT (white) wire. If you
short the shield to the PTT wire it should trigger the radio
to transmit. It could be the radio needs a better PTT line.
I have an interface reed relay modification that might help.
Contact me for more information.
- Now we need to set the transmit level. Plug
in the white audio cable to the computer line-out or
speaker. Make sure the interface pot is set at
about the 1/2 way point.
- Click on CQ and see what happens. If you have
another radio listen to see if you hear your signal.
Turn the computer soundcard line-out or speaker level until
the ALC just starts to move, This is about the best level.
If in doubt of your level, make a contact on PSK and have
them tell you what your tracks look like. If they're
wide, then you would need to turn down your level.
It's best to error on the low side.
A great place to find the pins of your
Known radio connectors ( Please check
your manual to make sure these are correct )
||Audio In W/OR
|Kenwood TS-140S, 450, 570D ,690
use 13-pin DIN male
13-pin DIN male
6-pin mini-DIN male
|Icom FT-756, use
8-pin DIN male
If all the above works, then happy Digital Mode. Once
you are comfortable let'st put this baby in a box ..
The Club Website will have the latest version of
Take a look at
contact me at firstname.lastname@example.org