Re: [amsat-bb] Source for 1.2 Ghz yagis

[Charles Suckling <charlie@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>]

At 15:49 02/08/2004, Ronald I. Nutter wrote:
>Since one of the modes for AO-51 will be 1.2 ghz uplink, I am looking
>for a source of this type of antenna.


Ron

My understanding is that the L-Band antenna on AO-51 is linearly 
polarised.  Given this, my first choice for an uplink antenna would be a 
circularly polaised one (eg a simple helix), provided that this will have 
enough gain, in order to compensate for the probable uncertainty in the 
plane of polarisation at any given time.  Yes, there is a 3dB penalty but 
hopefully much reduced fading.  I used this method on AO40 K-Band to get 
round the fading problem and it worked very well.

I haven't seen the uplink requirements for L-Band on AO-51 - probably 
haven't looked in the right place.  Once we know this, should be easy to 
work out if a helix would do the job.

73

Charlie G3WDG 
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