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Re: Tonna 2x19 70 cm + polarity switching



Ib,
I hope all is well at the UofC.  
Your comments are in complete agreement with my "field" experience as well.  
I was really surprised at how often AO-27 and AO-10 change polarity.  

One note I might add, is RS-13 seems to not matter much on which polarity 
with a slight preference for RHCP, but RS-15 seems to prefer LHCP always 
(when there's anybody to talk to).

The only disadvantage of using LP antennas is the narrower beamwidth required 
to get the same effective gain as CP--making pointing more critical.  
73,
Jerry, K5OE


> The switching between Right Hand Circular Polarization and Left Hand is 
> useful at times. I have 
>  tested it on FO-20 and FO-29. In both cases it has a clear advantage to 
> fixed Right Hand Circular 
>  antennas. 
>  On some of the UoSATs it does not make much difference. This is a good 
> indication since they are 
>  linearly polarized.
>  On AO-27 it can make all the difference between a very good signal and no 
> signal - much to my 
>  surprise. The antennas on this satellite are linearly polarized.
>  On AO-10 it sometimes makes a lot of difference to change. This is in good 
> agreement with results I 
>  have seen before.
>  
>  After a couple of month experimenting with the switch I feel it is safe to 
> say that it is an advantage to 
>  be able to switch - but I think it is much better to use linearly 
polarized 
> antennas if you are a 
>  newcomer to satellite work. The disadvantage is not very big.
>  FO-29 change polarity very quickly - at least when it is to the West of me 
> here in Copenhagen. That 
>  makes the operation a bit difficult if you use switching.
>  
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