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Re: AO-40 reception on 78 Turn Helix



The copper tape is 250 wide not thick. Amazingly, the tube does not sag at
all because it is very light. I used a transparent tube that is about 8 feet
long. It is the exact diameter required and I bought it at ACE Hardware. It
is used to cover flourescent light tubes so if they chatter that the glass
does not kill someone. The material seems to be a lot better than PVC and
very light. I really recomment it.

Pieter

----- Original Message -----
From: "Vince R." <vincesr@ij.net>
To: <amsat-bb@AMSAT.Org>; "Pieter Ibelings" <elpieter@hotmail.com>
Sent: Friday, May 11, 2001 10:25
Subject: Re: [amsat-bb] AO-40 reception on 78 Turn Helix


> > I just finished building a 78 turn helix for mode S. I had already
tested
> > the helix antennas at the short end of the range. Now it is time to test
it
> > at the other extreme. This antenna is almost 8 feet long. It is wound
like
> > all my other helixes on a transparent plastic form and using copper tape
of
> > .250 thickness. I have tuned it and it gave me about 1.2 SWR. I plan on
> > testing it on tonights pass.
>
> WOW!
> You have great patience!
>
> I will be curious about how you finally end up mounting it to prevent
> sag. It would seem that any misalignment on the order of a inch or two
> may affect the performance. Please post the details of your support
> bracket. Also, is the tape really .250 thick? Maybe it is foil that is
> .250 wide? I'm a little confused there... Or are we talking mm ?
>
> My son, KD4YJB, Vince,  is ready to build one of these!
>
> Thanks for sharing,
> Vince KD7AI
>
>
>
>
>
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