Wing-tip Vortices on 2m WSPR

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Wing-tip Vortices on 2m WSPR

Post by VK2KRR » Fri Aug 17, 2012 6:50 am

I just thought I should draw attention of any people interested to this post on the WSPR page -

Wing-tip Vortices on 2m WSPR, by Glen N6GN.
Leigh VK2KRR
The Rock Hill, NSW

Station monitoring Tropospheric & Ionospheric propagation 24 hours a day

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Re: Wing-tip Vortices on 2m WSPR

Post by VK2GOM » Fri Aug 17, 2012 8:04 am

Hi Leigh, interesting stuff. I am sure I have seen a similar trace on Spectrum Lab when I have been monitoring TV stations and looking for meteor echoes.

Also, these vortices are not constrained to just wing tips... They are more rightly called trailing edge vortices. Because the air flow over an aerofoil section takes two different paths; it converges towards the centre of the aircraft on one side of the wing/tailplane and diverges on the other side, this sets up the rotating vortex.

I have seen plenty of pics of military aircraft with TEV's forming both from the wings AND the tailplane. This (if the reflection theory pans out) would leave an even bigger medium in the sky in which to work on.

73 - Rob VK2GOM / GW0MOH

PS. as an example, a tailplane TEV forming on an F15; photo taken by a friend from Uni back in the UK, stood on a hill in Wales in the 'Machynlleth loop' low flying area. ... -0445c.jpg

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Re: Wing-tip Vortices on 2m WSPR

Post by VK3DXE » Fri Aug 17, 2012 10:36 am

Awesome photos Rob!

I used to live right under the flight path into Kingsford Smith in Sydney, from my shack I had a direct line of sight down the flight path. The intensity and duration of vortices from some aircraft were such that you could hear them quite regularly. I often experienced quite interesting doppler effects on 2m SSB signals. Back when Spectran first became available, I was suddenly able to see the effects on my computer screen, particularly on a beacon signal, quite fascinating stuff.

Spectran is great for observing similar effects on meteors when monitoring a distant beacon. I have some great screen grabs of space junk during re-entry where you can identify the main body and various bits falling off - some denser ones speeding up, while less dense ones lag behind. Occasionally you can also identify rotation of a large item by the doppler pattern. I plan to have more of a play with the "3-D" display in Speclab to see how it looks when you get a rotating item of space junk re-entering the atmosphere.

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