[amsat-bb] Re: Turnstyle antena

["Dirgantara YF0EEE" <enggi1401@xxxxxxxxx>]

hi Gordon

if I use home brew it is possible in space ?, Sun solar hardener it possible
damage the antenna
any solution ?  Factory build ? if possible already tested in hardener and
for Space use.

btw want to use in VHF and UHF

thanks

de YF0EEE


----- Original Message ----- 
From: "Gordon JC Pearce MM3YEQ" <gordonjcp@gjcp.net>
To: "AMSAT-BB" <amsat-bb@amsat.org>
Sent: Tuesday, October 14, 2008 2:44 PM
Subject: [amsat-bb] Re: Turnstyle antena


Dirgantara R - YFØEEE wrote:
> hi
>
> Any body know ?, in where i can buy Turnsytle antena for LEO Sat ? and
> cheap.
> I have some project testing Prototype LEO Sat.
>
> 73 de YF0EEE

Turnstile antennas are actually pretty easy to make.  At its simplest,
it's four bits of wire about 1/4 wavelength long, with a 1/4 wavelength
phasing loop joining them.  Note that the lengths of the elements and
the phasing loop are going to be actually 1/4 wavelength multiplied by
the velocity factor, which for the elements will be so near unity it's
not worth bothering with (make them a tiny bit shorter *if* you need
to), and for the phasing loop will be dependant on the cable used - 0.66
  for RG58.

You haven't said which frequency range you want the antenna for, but on
UHF I've had excellent results with the K5OE antenna, and I've also had
a lot of success with the "cheap yagi" designs by WA5VJB.  The latter I
found a bit "narrow" to tune, though.

Gordon
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