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

Re: 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



AMSAT Top AMSAT Home