[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: 5 1/2 turn helix for offset dish



I'm attempting to use Jerry's K5OE method of leaving the insulation on the
first 1/4 turn and press it flat to the ground plain.  I have no test gear
so I was going after the easiest to reproduce.

73,
Joe
ka0yos@amsat.org

----- Original Message -----
From: "Ken Koster" <n7ipb@koster.seatcp.net>
To: <ASTROHAM47@aol.com>; <amsat-bb@AMSAT.Org>
Sent: Saturday, August 03, 2002 6:46 PM
Subject: Re: [amsat-bb] 5 1/2 turn helix for offset dish


> I'll add in my 2 cents as well.
>
> I built the helix for my 1.2 meter dish without attaching the foil or
brass
> shim at all.  Instead I just made sure the first quarter to half turn was
> flat and relatively close to the reflector before I let it curve away to
> form the rest of the helix.  Using #6 copper wire I don't need a support
> and the swr as measured on an HP network analyzer was 1.2 to 1 at 2400MHz.
> I think that's acceptable.
>
> As others have said, the helix is broadband and forgiving, just build one
> and try it out.  You will probably be pleased with the results.
>
> Ken,  N7IPB
>
> On Saturday 03 August 2002 08:41, ASTROHAM47@aol.com wrote:
> > Can anyone help..who has made a helix for offset dish...I have gotten
info
> > off of several web sites...one refers to flattening the 1st 1/2 inch of
the
> > helix..and soldering  coax foil sheild to it?? making matching
section...I
> > do not  understand what to do here...I know you dont want the helix to
> > touch the reflector....
> >
> > Mike Miller KA5SMA
> > ----
> > Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> > To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
> ----
> Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
> To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org
>
----
Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org



AMSAT Top AMSAT Home