[amsat-bb] Re: Polarity questions

Jim Jerzycke kq6ea at pacbell.net
Fri Sep 19 09:34:30 PDT 2008


Theoretically, it's 'infinite', but out in the real world, expect around 20~25dB loss from being completely cross-polarized. When I was doing commercial satellite work, if we could get 26~27dB we were happy, but this was with rigidly controlled satellites and commercial ground stations.
Between linear and circular, expect about 3dB loss.
Jim  KQ6EA

--- On Fri, 9/19/08, Tim Tapio <tim at timtapio.com> wrote:

> From: Tim Tapio <tim at timtapio.com>
> Subject: [amsat-bb]  Polarity questions
> To: amsat-bb at amsat.org
> Date: Friday, September 19, 2008, 5:58 AM
> Hi,
> 
> How much signal reduction is there as the result of having
> the wrong
> circular polarization?
> I'm looking at M2 circular antennas for the 70cm
> downlink, it's another $200
> for the switching to change polarity (woo hoo).
> 
> 73 de Tim, K4SHF
> 
>  
> 
> 
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