[UK-CONTEST] Aircraft Reflection

[Giles Herbert]

I believe you are referring to a two part article in the Bulletin Called "A little Flutter at VHF" Written by Paul Sollom G3BGL.  If I remember right, and I visited him at the time of the articles, it was monitoring the vision carrier of the French band 3 TV tx at Lille from his location near Thatcham in Berkshire.
 
Another sytem to use these reflections is Bistatic Radar.

Giles Herbert
G0NXA



 
> Date: Mon, 21 Mar 2011 19:06:17 +0000
> From: clive at gw3njw.net
> CC: uk-contest at contesting.com
> Subject: Re: [UK-CONTEST] Aircraft Reflection
> 
> Not directly relevant, but I remember many years ago in the Bulletin ( 
> probably still was the Bull. back then!) an article on aircraft 
> reflections, I believe it was on 144Mhz, using beacons of the era as the 
> subject matter.
> 
> The article discussed the interference between the direct path and the 
> aircraft reflection, giving the familiar variable speed " chuff-chuff " 
> sound of the received signal. The author- who was somewhere on the South 
> Downs if I recall-. also commented upon the special situation, when the 
> " train came into the station", i.e the frequency of the chuff chuff was 
> briefly zero, and the signal was steady. iirc He provided a mathematical 
> proof that this occurred precisely when the aircraft, the beacon, and 
> the receiving station were all on the path of a common ellipse. He then 
> showed that there were in fact a number of such ellipses so that the 
> train could come into the station, stop, leave and apparently repeat the 
> process at a " different station"! Of course, this was in the era when 
> thee used to be interesting articles in Radcom as now is, rather than a 
> collection of special interest sections, which in totality are probably 
> only of interest to the polymath :-(
> 
> In fact, as I write this I am hearing just that sort of reflection on 
> the Cornish ( GB3MCB) beacon on 6m, albeit with my ( handraulic) rotator 
> fixed to the East. However that particular train has never come into the 
> station , suggesting that the aircraft did not cross an ellipse on which 
> both myself and GB3MCB (50042.5) are located, hardly surprising since 
> our antennae are mutually at right angles.
> 
> Of course, even HF operators in south GW hear not dissimilar 
> reflections, on other GW signals in the South ( well on CW anyway), and 
> there is little doubt that these are from the hills to the North of each 
> of us ( aircraft presumably being too small to reflect HF signals?), but 
> why the reflection exhibits a periodicity is not clear to yt, but one 
> might postulate that it is something to do with the wx conditions. The 
> periodicity of these reflections is interestingly very similar to those 
> heard on W6 signals
> 
> Zut alors, this is nothing to do with contesting, so I'd better QRT!
> 
> 73
> 
> 
> Clive
> GW3NJW
> 
> On 21/03/2011 17:50, Ray James wrote:
> > Hi all,
> > Following my talk at last years convention and on-air activities, I get regular requests for more information on the use of aircraft reflection as a means of nabbing some nice distant contacts under flat tropo conditions and contests on UHF and Microwave bands.
> > Much of the content from the memory stick is retained for club talks I do but aircraft reflection appears to be to the most popular personal request.
> > I have therefore added a page to my website on the operational side of the subject and trust those interested will find it useful.
> >
> > http://www.rayjames.biz/gm4cxm/id28.html
> >
> > 73 Ray GM4CXM
> >
> >
> >
> >
> > _______________________________________________
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> > UK-Contest at contesting.com
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> >
> > 
> 
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