[Moon-net] Circular polarization?

[Leif Asbrink]

Hi Heinz and all,

> I Würzburg I learned, that some 2m-EMEers drive each part of 
> theyr X-pole antenna simultaniously from two separat PA´s. 
> So they stay with each PA within the powerlimitation of theyr 
> country and prevent from loosing 3 dB by splitting the signal 
> into H und V.
> Someone told me, he would use circular polarization in this way.
With a very small modification someone using this setup
could gain 3 dB. Just insert a hybrid (rat race) between the
power amplifiers and the antenna. With a phase shifter at the 
drive side of the power amplifiers it will be possible to
send all the power to H or V or any other linear polarisation
in between. (What tx polarisation to select can be computed
from the polarisation of the received signal. Linrad does this
automatically but it is fairly easy to do manually)

> Due to my knowladge I would loose 3 db by receiving a 
> circular polarized transmission with a horizontal 
> polarized antenna.
> Wouldn`t it be better to feed the two parts of my X-pole 
> antenna in phase (or near to that) and let the antenna 
> of my QSO-partner find out witch signal, my H or my V, 
> comes best for it?
If your qso partner uses Linrad and an X-pol antenna it
does not matter at all. Linrad automatically adapts to
whatever polarisation you choose to transmit:-)

Linrad (Linux Radio) is now available for Microsoft Windows.
It is not yet 100% stable, but in most cases it runs well
under Win 98, 2000 and XP. Linrad is not particularly user
friendly. You might want to use Winrad on H or V for some 
time to become used to a new way of operating your receiver
before investing time in learning how to use Linrad....

73

Leif / SM56BSZ




> 
> Would be fine to get some answers.
> 
>    73 and hear/see you via the moon
> 
>         Heinz, DM2BHG
> 
> _______________________________________________
> Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html
>