Noise is a frequent topband topic and consideration. Here is a germ on an
idea - I dont know if new or already well known. When I was in Thailand in
1964 (as HS1L) we had a research lab for Stanford Research Institute. Lots of
communication research. One project was recording satellite Faraday rotation
data.
The Bangkok noise and our ionospheric sounders made that difficult. We had
a good technician (engineer?), Bob Daniels (sk) - Fred K3ZO may remember his
W6 call, who built a noise reduction system.
I cant remember the details and wonder if topbanders might see if this would
work for topband.
We used two receivers, and used the IF outputs from those to drive a
comparator. In one input was N; and in the other input was S+N, and the
output was
the difference or S. We got good recordings and could not have without that
system. It requires the same phase thru both paths for the comparator to
work.
I have two TS-850's, which have an 8.83 MHz IF output. I wonder about the
comparator circuit and what circuitry to use beyond that, or whether to try
and insert that back somewhere into the 850?
This system may be one used by Motorola in some of their equipment. It
requires finding a "clear" noise frequency near the desired signal frequency.
It
is a lot more effective than a noise blanker which tries to blank out noise
pulses.
Thailand was fun - highlights were visiting the ancient jungle temples of
Angkor Wat in Cambodia, and the annual elephant roundup in Thailand. Pileups
with HS1L were like those from VQ3,4,5 in 1948.
I enjoyed too the chance to help found RAST in Thailand.
Here's for low noise and lots of good signals in 2007. 73 Bob W7LR
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