[TenTec] Radio Science + QSK = Radar

[ROBERT CARROLL]

Martin-

Echoes are fairly common.  I ran into them on 17cw last week.  When I
finished a word etc I still heard about a dash worth of myself.  It was a
little disconcerting.

Bob W2WG

-----Original Message-----
From: tentec-bounces at contesting.com [mailto:tentec-bounces at contesting.com]
On Behalf Of Martin, AA6E
Sent: Monday, January 02, 2006 1:21 PM
To: tentec at contesting.com
Subject: [TenTec] Radio Science + QSK = Radar

When operating QSK at 15-20 wpm, I am running into echoes of my
transmissions.  These occur on certain azimuth bearings at certain
times of day, most often to the SE, which is over water until hitting
S. Africa or Antarctica from here.  I've seen this from 20 M to 15 M,
at least.

Rarely, I think I've seen long-path echoes that come back to me from
the opposite azimuth. (The SteppIR bidirectional mode picks them up.) 
More often, the return bearing is the same as transmitting.  I haven't
been able to measure the delay time accurately, but it is roughly 2
dit (element) times at 25 wpm (about 50 msec), indicating a 10,000
mile roundtrip.

It seems to be a real effect.  I can get rid of it by changing azimuth
or using a dummy load.

My question is whether other ops see this and whether it has been
written up anywhere in "ham space".  These are not the "long delay
echoes" that people have claimed to see.  The radio science community
does run HF radar to study fluctuations in the ionosphere, and this
phenomenon is probably well known to them.

The Orion makes a fair radar set, as it turns out.

73 Martin AA6E
--
martin.ewing at gmail.com
http://blog.aa6e.net
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