[Moon-net] 10GHz Polarisation

[Brian Coleman]

Hello All

Anyone interested in the 10GHz polarisation discussion  may be aware that 
with others various tests are being conducted to try and establish whether 
circular polarisation will be advantageous at 10GHz or not. Some results are 
posted on my web pages at http://myweb.tiscali.co.uk/g4nns/Poltests1.html . 
In my view, there are further tests to be done before a balanced conclusion 
can be reached.

At present my view is that for inter EU or EU - US contacts following the 
convention of EU vertical and US horizontal the benefits of circular will be 
marginal at best. If the circular system has more than about 1dB of 
elipticity or if the circular polarizer system involves coax, particularly 
on the receive side, that marginal advantage could be negated. Where both 
these are true I doubt there will be any useful advantage.

If anyone wants to continue this discussion and analysis AFTER the other 
necessary tests have been done I would be pleased to hear from them. The 
tests which are needed include:- Circular to Circular and Circular to 
rotateable linear (perhaps concurrently with the cp-cp test). When that data 
is available a balanced discussion will be possible.

My thanks to the AMSAT DL team at Bochum,  the OK1KIR team and the IQ4DF 
team for their help with the tests done so far.

If anyone is put off from coming on to 10GHz EME because they feel they must 
have the additional complexity of a circularly polarised system that would 
be a pity.



73 Brian G4NNS
Currently 9W, 3.7M, remote controlled linear polarisation, 24 initials on 
10GHz.
I have a choice of circular or linear on 3.4 and 5.7GHz but so far all QSOs 
have been with linear.
PS anyone for circular on 24GHz.....