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Re: To helix or Not to helix



CP does work better and you don't need much gain when feeding a dish.

73,

John
KD6OZH

----- Original Message -----
From: "Mark L. Hammond" <hammond@surrealnet.net>
To: "Pieter Ibelings" <rfspace@yahoo.com>; <amsat-bb@AMSAT.Org>
Sent: Wednesday, 30 May 2001 19:33 UTC
Subject: Re: [amsat-bb] To helix or Not to helix


> Neat information...thanks for sharing, Pieter.
>
> What about a loop yagi feed for a dish??  Sounds like a fun thing....
>
> 73,
>
> Mark
>
> At 02:26 PM 5/30/01 -0400, Pieter Ibelings wrote:
> >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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> > > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
> > >
> >----
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>
>
>
> Mark L. Hammond  [N8MH]
>
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
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