SatSig topic:

Please help the polariser

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Jan 9^th, 2008 at 11:42am

Please help
I need to get Intelsat signal IS904 for C band broadband service the provider asks me to change the antenna to circular polarization and I lost the polarizer what I have to do ?
Can any polarizer work for me or I have to get the same one
Please tel me where can I fond a new polarizer my antenna now is circular
I'm near the equator somalia

Jan 9^th, 2008 at 2:44pm

You need to contact the service provider again and tell them the type of antenna and ask if they can send you a new polariser, plus gaskets and nuts, bolts and washers.

The polariser is typically a long straight, square or round tube with two rows of slots or pins along opposite sides.

When you install it, the lines of slots or pins need to be at 45 deg, one way or the other, from the linear polarisations of the OMT assembly where the LNB and BUC attach.

The two alternative 45 angle possibilities give Right Hand or Left Hand polarisation on receive. The OMT has the linear signals at right angles so the transmit polarisation is opposite to the receive polarisation. e.g. Right Hand receive and Left Hand transmit.

If you select the correct 45 deg position you will receive a perfect signal. There is no need for any rotation adjustment. If you select the wrong 45 deg position you will receive no wanted signal at all.

If you install the polariser half way (wrong), so that the pins are in line with one of the linear polarisations, the polariser will have no effect (except for slight attenuation loss) and you will still be in linear polarisation mode, as if the polariser were not there.

If you say here what is your antenna type maybe someone in Somalia has an unwanted polariser.

Best regards, Eric.