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Re: 2mtr dish (additiona)l



Hello !

I'm using a 2m Prime focus Dish with f/d 0.7
I was using my old 3 turns L/S feed (1m Dish f/d 0.35)

Since yesterday I'm using 7 turns helix feed on S-Band but this morning 
Squint was too high (35 deg) to have good
comparaison reports but it seems to be better

Here the double-feed L/S mode link (some parts in french) but look at the 
EXCEL sheet (with this you can see
on a picture how your feed illuminate the dish)

http://www.f1te.org/Double%20Helice/HELICE.htm

I'm using 3 turns on L band (I've done a modification only on 13cm on my 3 
turns/3 turns L/S feed)
Will try tomorrow morning (local time) on AO-40 ...

My UPLINK is 12 el. Quad H polarity and it's better than 19el Crossed YAGI 
! Why ? I don"t know !

73 de YANN - F1NGP


At 20:38 01/10/2003 +0800, VK6XH wrote:

>First of all many thanks for all the email responses to my original post,
>there are some clever people out there !!
>I've decided to go with the dual helix feed for mode S & L and to build a
>separate uplink antenna for 70 cms ( still undecided on a 14 turn helix or
>17 ele each side crossed yagi)
>Now there is a separate problem, for a 0.656 f/d dish some of you recommend
>a 6 turn helical for each band and others say 2.5 turns or three turns, who
>is right ??
>Also I have searched the net for any drawings of a dual  S/L helix feed and
>drawn a complete blank.
>Once again I would accept any useful information.
>Again , many thanks for your previous responces.
>73 de Keith VK6XH
>

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