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Hi Gary,
this is excellent, and much appreciated! I had
basically tried to provide a readable signature on Chris' grabbers, but in
the end QRSS 1200 turned out to be a bit fast for those. I guess
the general concept is more suitable for straight unmodulated
carriers...
Your screenshot reveals my transmit
instability near the end of the "N", when my (DHO-based) samplerate locking
temporarily failed, and the audio frequency jumped by 20 mHz.
Do you have plans for further optimization? The
Loran line visible on 137780.419 (Anthorn et al) may come in handy to
evaluate sensitivity and stability during development.
One thing I would perhaps suggest is to
activate the "one pixel per FFT bin" option in Speclab. If you don't, and
zoom in instead, the brightness of each pixel is driven by the highest
power from a number of adjacent FFT bins, which in effect increases the
visible noise level significantly. Of course
the downside is that the visible range becomes quite narrow, requiring TX
stations to cuddle closely around a prescribed QRG to be seen on the
grabber slot. On the other hand, you can still move the slot around a
posteriori, and manually search for possible missed activity.
Best 73, and thanks
Markus (DF6NM)
Sent: Saturday, September 24, 2011 12:26 PM
Subject: LF: DF6NM 23-09-2011
Hi Marcus, LF,
Please forgive the frequency accuracy & stability on my experimental
very slow (2 mHz) SpecLab screen but the signal is clearly visible.
Receiver - JRC NRD-345
Antenna - PA0RDT Mini-Whip at 9 metres
73
Gary - G4WGT
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