Topband: Echo on 160m yesterday morning

[Andy Cook]

I think this form of ducting takes place way above the layers of the atmosphere where weather happens. In my experience the magnetospheric ducting is normally localized in impact. If this was really happening in multiple places around the world at the same time on this occasion then I think that is unusual.

Andy, G4PIQ

-----Original Message-----
From: "K1FZ-Bruce" <k1fz at myfairpoint.net>
Sent: ‎06/‎02/‎2017 13:46
To: "g4piq at btinternet.com" <g4piq at btinternet.com>; "Topband" <topband at contesting.com>
Subject: Fwd:  Echo on 160m yesterday morning


 

Hi Andy,

Ducting takes place over a relatively small area.  Depends upon cloud layers and temperature zones

This event took place   ~ world wide.   Band openings between North America  to Asia, and Australia.

73
Bruce-k1fz
http://www.qsl.net/k1fz/beverage_antenna.html




 On Mon, 6 Feb 2017 12:20:07 +0000 (GMT), Andy Cook  wrote:

I think you'll find this was Magnetospheric Ducting. Take a look at some of the articles here http://la3za.blogspot.co.uk/search/label/Unusual%20Propagation and here http://folk.uio.no/sverre/papers/2009_MagnetoDucting-QST-LA3ZA.pdf. 
Delay depends on your latitude - but couple of hundred millseconds is about right and this is a peak time of year for the effect. 
I've heard this quite frequently on 80m around mid local-evening during the winter, and one occasion - on 3rd Feb last year - very strongly indeed. That night I was able to hear my echoes with just 25mW into a dipole on 80m - but it's often strong enough to be audible with a few watts. I've read papers which suggested it does also occur on 160m.
Reports of these being less strong / gone when you switch to a vertical look plausible as well since they apear to require vertical incidence from the ionosphere.
73,
Andy, G4PIQ 
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