RE: [linrad] question regarding LINRAD

[Leif Asbrink <leif.asbrink@xxxxxxxxxxxxxxxx>]

> I'm planning to use two different antennas on Linrad . They are different 
> in the way that the H pol antennas will be 16*3WL and the V 
> antennas , not 
> yet decided , but something like 16 short yagis , 1.5wl long occupying 
> half the boom of the 3WL. ( stacking distance to use remains a pb yet)
> My question is :
> as the gain will not be the same on V and H , will linrad be able to show 
> me the right polarisation offset , for me to calculate correctly wich pol 
> I should use on TX?
At the present time NO.

The error will not be very large. Presumably the gain difference will be
in the order of 1.5 dB with an amplitude error below 20 %.

H and V will come out correctly (of course). With a true polarisation
of 45 degrees, Linrad will indicate something like 38 degrees. In case 
you have only H or V available for tx you might choose the wrong one 
but it is not too bad.

> In case there's an error , could it be possible to add an amplitude 
> calibration factor , telling linrad : my V antenna has xx db gain , my H 
> antenna has xx db gain. and maybe some phase calibration factor , because 
> there's a large position offset  between the two antennas ( V antenna abt 
> 1.5 lambda or so ahead of the H)? thus it will no longer be necessary to 
> compensate via feeding cables phases.
This is certainly possible and not difficult at all. It would be
enough with two parameters: Amplitude difference and phase difference.

73

Leif

SM5BSZ





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