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Re: helix location vs focus



Oops, I just re-read your message.  Yes, adjust the
helix for the maximum signal, and use the sun to find
where on the helix the focus ended up being.  Good idea!

Greg  KO6TH


>From: Dave Guimont <dguimon1@san.rr.com>
>To: "Greg D." <ko6th_greg@hotmail.com>
>CC: amsat-bb@AMSAT.Org
>Subject: Re: [amsat-bb] helix location vs focus
>Date: Thu, 06 Jun 2002 23:32:45 -0700
>
>
>
>>>   I read somewhere (can't remember) that you should place the
>>>   bottom (i.e. feedpoint) of the helix at the focus of the dish.
>>
>>I seem to recall someone on this BB experimenting, and finding
>>that the hot spot was at the end of the first turn for a simple
>>helix.  My own experiments seem to put the hot spot at the mouth
>>of the can, for "canned helix" antennas.
>>
>>The best thing to do is to create (or locate) a weak signal
>>source, and adjust it for best signal.  Then, let the rest of
>>us know where it is!
>>
>Hi Greg et al,
>
>Very simple to determine, and it is very close to that.  I've been winding
>and testing them since O13.
>
>Glue half a dozen ~1" mirrors scattered around the dish. I use them to
>determine
>the mounting length and approximate position for the helix.  Tune on a 
>steady
>beacon, and adjust for max smoke.  Then point back at the sun and 
>inter-leave
>a small piece of paper for the bright spot; hot, if u will....
>
>----
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