[Lowfer] VD in PSK31 on 13555.400

[Jay Rusgrove]

Ed

Agree. Same is probably true at 13 MHz.

PSK31 clips along at a good rate so it can take advantage of any short =
duration propagation. PSK08 might offer some advantage if conditions =
were stable and signals were weak. Think I might try sending just VD VD =
VD instead of the longer message that's currently running to take =
advantage of any "scatter".

I'm using Spectrum Laboratory's digimode feature to generate an on/off =
tone .wav file for PSK08 and PSK31.
The exciter is the tracking generator output from an HP 3586C referenced =
to GPS. This feeds a pin diode switched 180 degree phase shift circuit =
(23' of rolled up RG-174!) with the switch driven by the rectified .wav =
file. It's then further amplified and fed to a dipole @ 60'. Not very =
elegant but it seems to work. Will probably replace the RG-174 with a =
hybrid at some point.

Jay=20

  ----- Original Message -----=20
  From: Ed Phillips=20
  To: lowfer@mailman.qth.net=20
  Sent: Tuesday, March 30, 2004 11:42 AM
  Subject: Re: [Lowfer] VD in PSK31 on 13555.400


  Jay Rusgrove wrote:
  >=20
  > Lewis
  >=20
  > Looks good.
  >=20
  > John is probably right that PSK31 is better suited to this frequency
  > range than PSK08 - sure is snappier anyway.
  >=20
  > Thanks again for watching.
  >=20

  A few months back  and I tried 80 meter beacons alternating between
  PSK31 and PSK10AM, using the "MULTIMODE DIGITAL TRANSCEIVER".  The
  conclusion was that when there was no QSB the slower mode had a slight
  advantage in low S/N, but lost more time in resynchronizing after a =
deep
  fade. where one would expect  180=B0 of carrier phase shift.  The net =
data
  rate was quite a bit faster with PSK31. Confusing the test is the fact
  that the same encoding is not used in the two modes, but I'd suspect =
the
  results would be the same with PSK08.  [What program are you using for
  it?]

  Ed
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