That's good information, Jerry!
What we need, rather than relying on antenna patterns for direction, is
direct phase measurement between a pair of vertical elements - with a third
element (or a pair) to resolve F/B ambiguity) if well calibrated , such an
array can be quite good for direction-finding measurements -but a good bit
of engineering is required to do the phase measurement. I worked on an array
like that for VHF marine radio years ago - worked quite well -mounted on
boats and Coast Guard cutters. Then what we would need to pin down the
origin would be at least 2-3 of such arrays at more or less right angles to
the source for good triangulation. When I'm not so busy, perhaps I can do
some design work on the phase measurement. Best approach is a system that
commutates digitally between the antennas to compare phase.
73,
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of K4SAV
Sent: Saturday, November 02, 2013 10:53 AM
To: topband@contesting.com
Subject: Re: Topband: Steady Carrier on 80 CW
I think I can do a little better on estimating the direction (better than SE
which I gave earlier). I can get two 30 dB nulls out of my receiving
antenna by switching directions. Those nulls appear at 145 and 133 degrees.
Pointed SW the signal is S9 this morning. In the null at 133 degrees the
signal is S0 and not audiable. The signal is considerably stronger at the
145 degree null. So my best guess is 133 degrees from Decatur, Alabama
(north central Alabama).
Oh! As I was typing this, at 1353 UTC the signal on 3501.6 abruptly
stopped. It was still at S9 just before it stopped. Then at 1355 UTC it
came back but with RTTY for about 15 or 20 seconds, and then back into its
continuous unmodulated carrier mode at S9. The RTTY burst was too fast for
me to boot an RTTY decoder to see if I could copy anything. I suspect this
is not an unintentional radiator.
There is very little QSB on this signal. I was waiting to see if the signal
amplitude was going to go down after sunrise. At 2 hours after sunrise it's
starting to show signs of QSB. It went down to S4 but now its back up to
S8. Now at 3 hours after sunrise it's S7 with QSB on my vertical, but only
about S1 on my low dipole.
A line of 133 degrees from my location goes thru Jacksonville, Fl and also
thru that long chain of islands, Nassau Bahamas, Turks and Caicos, and Haiti
and Dominican Republic. Most of Cuba would hit my 145 degree null, but
Guantanamo is close enough to be a candidate (with a little measurement
error).
A measurement from Florida would be interesting.
Jerry, K4SAV
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Topband Reflector
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Topband Reflector
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