SatSig topic:

Tooway polarisation setting

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Sep 20^th, 2009 at 8:59pm

The polarisation adjustment angle.

This needs to be adjusted to an accuracy of +/- 1 deg to avoid interference to others using the opposite polarisation. It is difficult to adjust the polarisation by local optimisation of the received signal as large adjustments, of say +/- 10 deg make negligible difference to the wanted signal but large differences to the interference caused by you to others.

For example if you misadjust your receive polarisation by 45 deg your wanted receive quality may drop by 3 dB, reducing your C/N from say 13 to 10 dB, equivalent to a mild rain fade at 19 GHz and not having much affect on your service. Your transmit bursts however will completely jam other peoples' services on the opposite polarisation. Their C/N will come down from 13 to 2.9 dB !

I suggest you set the polarisation adjustment angle by calculation. You can set it to 1 deg accuracy quite easily.

See:
Satellite dish pointing UK
Satellite dish pointing Spain
Satellite dish pointing France
Satellite dis pointing Greece
Satellite dish pointing Italy

Best regards, Eric.
.

Sep 23^rd, 2009 at 5:23pm

Twoway satellite is a linear polarisation system so requires considerably more skill to set up compared with Wildblue (circular polarisation) in the USA and Canada.

It is already clear that there are sites being installed with variations in polarisation that are not clearly explainable.

Please, if you install a Tooway dish, report its location and polarisation setting angle either here or to to me eric@satsig.net. If possible, say if the setting was achieved by calculation or by measurement, verbally from the Turin teleport or by local measurement.

Best regards, Eric.