Stefan wrote:
> Would the stability of my signal reach the requirements
> as well?
Is the antenna current stable? Then probably the short-term
phase is steady enough.
Your transmission on 2012-12-15 was upset by 'RF' getting into
your 10kHz reference but I think you got that fixed.
You would need to rig something up to reverse the phase
according to the pattern of 1s and 0s in a text file.
The computer that does that needs to have its clock tied to
UT by NTP. An audio transformer and a double-pole double-
throw relay will do the phase reversals. You could control
the relay using a bit on the PC parallel port or use one of
the modem control lines out of COM1.
Perhaps if you get the chance, send a one hour carrier to
give me an S/N measurement - then we can select a suitable
symbol rate. Best window is 07:00 to 11:00 UT but not every
day has a good noise floor - some days are very bad and completely
useless.
Anyway, I'm not quite ready for another test yet. Getting so
much out of the two signals from Markus, still much to do and
will have to alter the coding again and run some near-field
trials of that first.
Next test probably with rate 1/8 K=25 which could be the
strongest FEC code ever used for amateur radio. My best K=25
code is showing a bit of an error floor at higher S/N so I
have a bit of work to do on that too.
--
Paul Nicholson
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