[amsat-bb] Circular Antennas

[Jim Jerzycke]

Hi, Jerry


I'm guessing here that you mean the "bed spring on a stick" kind of 
normal-mode helix antenna that you point at the bird, rather than some 
other *omnidirectional* helical antenna like a Quadrifilar Helix 
Antenna, aka "QHA"


Well, I'm not really sure if they were ever "in fashion". They're pretty 
easy to build, pretty broadbanded, and are quite forgiving of minor 
errors in construction, but seeing as they have no way to switch 
polarization, which can be pretty handy at times, they're pretty limited.


I've built a couple, one for 1.2GHz, and another for 70cm, and they work 
quite well for being so simple.


One for 2 Meters is quite a bit bigger, and they start to get cumbersome 
to rotate.


Other than the two I built, I've never seen an Amateur Radio version "in 
the wild", although I have seen numerous ones for commercial and 
military use.


73, Jim  KQ6EA


On 08/12/2016 06:40 PM, Gerald Payton wrote:
> Trying to get back into satellite radio from the early 2000s, I wonder what happened to circular helical antennas.  Are they out of fashion now?
>
>
> 73,
>
> Jerry  AB5R
>
> EM12kh
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