[amsat-bb] To helix or Not to helix

["Pieter Ibelings" <rfspace@xxxxxxxxx>]

Hi Guys,

I performed some antenna comparisons yesterday between 3 different helix
antennas and a loop yagi. My results show that the loop yagis have a LOT
more gain for a given length than a helix antenna. The longest helix that I
have is about 23 turns and is about 6 inches shorter than the 21 turn
looper. The loop yagi was consistently about 1 S unit (6dB) better. The
linear to circular loss appeared to be inexistent.
I was going to stack four helix antennas and now I have decided I am going
to stack four loop yagis. I think I now need to get rid of all my 7 helix
antennas for a good price.

Here is the picture of the Loop Yagi sitting on a small vise on top of my
window.

http://ozoni.com/n4ip/DSCN0505.JPG

Pieter N4IP


----- Original Message -----
From: "C. Martins" <martins@vega.net.dhis.org>
To: <amsat-bb@AMSAT.Org>
Sent: Wednesday, May 30, 2001 1:40 PM
Subject: [amsat-bb] Helix lenght limit


>
> Hi all,
>
>   I've read several references on this list to the maximum practical
lenght
> limit of an helix antenna. It seems to be about 3ft at 2.4GHz, right?
>   However, consulting the ARRL antenna book chapter on helicals I didn't
find
> any reference to this matter. Can anyone give some explanation or some
link
> about how to know/calculate this limit vs. working frequency or something
> similar?
>
>   Sorry if this has been asked earlier, but couldn't read all the
e-mails...
>
>  Thanks for any info. Best regards
>
>   Claudio
>   CT3KD
>
>
>
> ----
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