I've seen the "long delayed echoes" people report, and they almost caused me
to run away from the rig in fear ! :)
But I've not seen "short delayed echoes" of the sort you report here.
73 de Gary, AA2IZ
----- Original Message -----
From: "Martin, AA6E" <martin.ewing@gmail.com>
To: <tentec@contesting.com>
Sent: Monday, January 02, 2006 1:20 PM
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@gmail.com
> http://blog.aa6e.net
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>
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