[amsat-bb] Re: Strange Signal - 436Mhz - (sample provided)

Bruce Semple bruce.semple at verizon.net
Tue Feb 8 17:12:32 PST 2011

Bob -
Thanks for running that down.
And you are exactly right - I could not get seem to get a signal strength peak
at any compass heading.

At 06:49 PM 2/8/2011, Bob Bruninga wrote:
> > Has anybody else heard this --
> > http://mysite.verizon.net/vzeqe0l7/Signal_436MHz.wav
> > The signal strength is not constant -
> > and peaks about every 10 seconds - -
> > A new radar perhaps?
>The 10 sec rotation rate nails it as an E6C Radar plane.  Probably operating
>off the East Coast.  I have been hearing it periodically for years, and
>getting ready for a satellite receive lab this week, it would have
>completely spoiled the lab.  So I spent over an hour on the web and on the
>phone and finally got in touch with the right folks and when I said "10
>seconds" they didn't need any more.  That nailed it to an E6.
>They are not supposed to operate on the UHF channel that overlaps the
>400-420 MHz band anywhere near land, but it is unclear what the guidance is
>for the band 430-450 where HAMS ARE SECONDARY.
>The above is my understanding, might not be exact.
>To locate it would be hard... Swinging the beam doesn't help much, because
>the radar is rotating at the same time and giving all kinds of fluctuations
>per second... which would mask your attempts at peaking on it.
>My best guess to locate it would be to get two hams on the phone separated
>by several hundred miles and to TIME the difference between the peak.  That
>would establish an angle from the radar between the two hams.  Then both
>hams compare signal strengths to an OMNI antenna (must be omni) and both
>must be calibrated for equal S meter readings.  The difference in peak
>signal strength would get an idea of range ratio between the two stations.
>That and the angle (and ignoring the mirror solution over land) would get
>you a good idea where he is operating.  (Maybe?)
>Bob, WB4APR

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