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Great Idea, I have been thinking along the same lines. There are
programs that allow the PC clock to be set within about a second to National
Standards using the internet. The PC clock could be set at the start
of a transmission and then there could be a window within the bauds to
do the FFT(s) --- drop a couple of seconds on each end of the baud.
I am a great fan of signal averaging.
I'll try to find the software for synchronizing the PC clock with our
Naval Observatory and send you a link. It's pretty nice and even
tells how far your clock was off prior to calibration. There is some
magic I don't understand about the network delays, but apparently they
have that pretty well solved.
Regards
Rye
Laurie Mayhead wrote:
Hi
all,I am very keen on exploiting
DFCW to its limit (after all its easy to implement) but it still needs
to be speeded up. Because of the lack of timing of the FFT bins they tend
to become blurred and it is neccessary to leave large gaps between elements
of a character with consequent waste of time.This is even more true with
QRSS. With DFCW the frequency change between dots and dashes adequately
separates them. Currently on T/A tests I have been using a 50 sec. period,
30 secs constitutes the transmitted element and 20 secs the gap ! What
a waste of time. Looking at the signal on my monitor (also see Uwe's pics,thanks
Uwe) these gaps are still poorly defined. I have thought about synchronising
the Tx and Rx using some form of universal time signal but 1) this might
be thought as cheatingand
2) the path variations, phase changes etc would be a problem. So my point
is WHY BOTHER ! would it not still be possible to read the message without
these gaps (they are hardly there anyway). For A to Z there is not much
of a problem since there are only two adjacent elements ie 2 dots or two
dashes, except for JO S H .But the numbers are a bigger problem. Anyway,
crazy perhaps but any ideas ? 73s Laurie.
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