[amsat-bb] Re: Turnstyle antena

[Gordon JC Pearce MM3YEQ]

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