Hi Simon,
This depends on the satellite and its attitude. For instance, Delfi-C3 carries circular antennas (canted turnstile) and is free tumbling. So you would need to switch polarisation as the satellite spins. FUNcube has linear antennas and also is free tumbling, so if you listen to it with a circular antenna there is no need to switch.
Note the following: Circular in the wrong sense gives 20dB of loss (listening to LHCP signals with an RHCP antenna and vice versa) Circular to linear gives 3dB loss (listening with a horizontal / vertical / diagonal antenna to a circular spacecraft or vice versa)
Now if the satellite is oriented or spin stabalised towards the earth, the polarisation will be known, and matching the apporopriate polarisation on the ground gives you the best signals.
Wouter PA3WEG
On Thu, Dec 25, 2014 at 8:17 AM, Simon Brown simon@sdr-radio.com wrote:
Hi All,
Is there a logical way to know which is the optimal polarization (left, right) for a LEO?
Simon Brown G4ELI http://v2.sdr-radio.com
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