[UK-CONTEST] Amazing echoes during CQ WW

[David]

This is entirely possible and even three round trips is detectable. Peter
Martinez, G3PLX has been doing some studies on this although he has been
using chirp encoding to get signal gain from processing the chirp. 

73 David G3YYD

-----Original Message-----
From: UK-Contest [mailto:uk-contest-bounces at contesting.com] On Behalf Of
Mark (G4PCS)
Sent: 30 October 2012 10:33
To: 'Uk-Contest at Contesting. Com'
Subject: Re: [UK-CONTEST] Amazing echos during CQ WW

I don't know if someone can check this: I tried to measure the echo's delay
and make it around 0.3264s. That equates to a distance of about 98000km -
allowing for errors that probably means a double-round trip?

I'm
 not sure how much delay would be expected within the receiver itself (the
EI7M audio is from monitor out), so the calculation might be way out - but I
suspect it's a lot further than backscatter ;)

73, Mark EI3KD at EI7M




>________________________________
> From: "Andy Cook, G4PIQ" <g4piq at btinternet.com>
>To: "'Uk-Contest at Contesting. Com'" <uk-contest at contesting.com>
>Sent: Tuesday, 30 October 2012, 10:13
>Subject: Re: [UK-CONTEST] Amazing echos during CQ WW
> 
>It is a great effect isn't it. I've always assumed that this was 
>sometimes backscatter rather than a full round-the-world trip, but I 
>expect that we see both kinds. I wasn't active at a 'real' station this 
>year, but I've certainly heard them as loud as on your recording in the 
>past. A great direction for this was always to the south-west in the
morning on 15m.
>
>On Friday night, I dropped into G0KPW to help Steve, G0AEV get the 
>station setup as M6T for a 10m single-band effort. I was surprised to 
>hear backscatter echoes as I went back to receive at 1930 local, 
>peaking with the antenna beaming about 280 degrees. I wouldn't have 
>expected a round-the-world path at that time of day.
>
>73,
>
>Andy, G4PIQ
>
>-----Original Message-----
>From: UK-Contest [mailto:uk-contest-bounces at contesting.com] On Behalf 
>Of Pete Lindsay
>Sent: 29 October 2012 13:13
>To: Uk-Contest at Contesting. Com
>Subject: [UK-CONTEST] Amazing echos during CQ WW
>
>We were once again blessed with great conditions during CQ WW, full 
>report from this year's M/S effort at EI7M to follow (headline = over
>9,000 QSOs!).
>On many occasions on 20, 15 and 10 we were hearing our own signals when 
>going over to receive, having travelled around the world. It seemed 
>much stronger and more pronounced than I have heard before, anyone else 
>notice that?
>
>Here is a sample recording on 10m for those who haven't heard the effect.
>You'll hear me from the monitor on the FT1000 during transmit, then me 
>again (peaking S9+) when I go over to receive.
>
>http://web.plcg.org/echo.mp3
>
>
>Pete, G4CLA.
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