[Moon-net] 10GHz Polarisation

[Luis Cupido]

Hi Chris,

All fine... I would like to be systematic if possible...

> the arguments of the advocates of the
> retention of the current polarization standard are also quite convincing.

And those arguments are ?

> Brian, G4NNS, has said, we need more information, but that means that 
> future
> tests need better planning.

Why is more information necessary ??
(besides more solid statistics)

The linear advocates based all their reasoning on the assumption that
depolarization was so severe that linear or circular would
be irrelevant, or quite severe that the circular advantage
would disappear because of the feed losses and circularity etc.

That is now well known to NOT be the case.
Depolarization was measured to be from -6dB to -10dB from
several independent RX recordings.
Polarizer and OMT designs are available, and not difficult to construct
and not lossy.

> Can I echo (pun intended!) Brian's other comment. If you are interested in
> joining us on 10GHz, don't let these discussions about polarisation put 
> you
> off!

:- )   Yeap... and how that would be ?
       In linear just because is easier ?
       or circular ?


Luis Cupido.
CT1DMK.



----- Original Message ----- 
From: "Chris Bartram" <chris at chris-bartram.co.uk>
To: <Moon-net at list-serv.davidv.net>
Sent: Saturday, September 30, 2006 1:12 AM
Subject: [Moon-net] 10GHz Polarisation


> Can we not let the discussion regarding circular/linear polarisation turn 
> into
> a crusade! Although instinctively I feel that CP is the right choice,
> particularly as activity (hopefully!) increases around the globe, and the
> Eu/NA axis becomes less important, the arguments of the advocates of the
> retention of the current polarisation standard are also quite convincing. 
> We
> need to examine the advantages and disadvantages of a change in a
> dispassionate way.
>
> When I get a few hours, I will analyse the available test results and look 
> for
> things like evidence of poor circularity. It's not _that_ difficult to do! 
> As
> Brian, G4NNS, has said, we need more information, but that means that 
> future
> tests need better planning. Unfortunately, there are few stations with
> facilities like calibrated adjustable linear polarisation. In my case, it
> would be a _lot_ easier to go circular than to arrange adjustable linear
> polarisation...
>
> Can I echo (pun intended!) Brian's other comment. If you are interested in
> joining us on 10GHz, don't let these discussions about polarisation put 
> you
> off! If you can find the Moon with a 1.8m or larger dish on 10GHz, and you
> have a tropo system which runs >10W with a reasonable receiver, you should 
> be
> able to make some contacts, particularly around perigee. Come and join us!
>
> As for 24GHz and up - at least there's not the temptation to try to use 
> coax
> systems on those bands!!
>
> Vy 73
>
> Chris
> GW4DGU
>
>
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