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Mechanical polarizer

A lot of motorised systems use a Universal LNB nowadays. This is good from the point of view of ease of installation and adjustment but it really is a compromise if you are dealing with any weak signals. Where a weak analogue signal might give a picture with terrible "sparklies", a weak digital signal can give a blank screen and no sound. You need to cut the losses as low as possible and provide an accurate adjustment for "skew" which is the rotational angle at which your dish receives the signal from the satellite.

The mechanical polarizer shown here is specially made for the Fibo feedhorn and has a C120 flange. A C120 flange LNB can be fitted onto the polarizer and this will allow fine adjustment of skew. A magnetic (coil) polarizer has losses, which the mechanical polarizer has not. Even though it only gives a little dB improvement, this can make the difference between receiving a watchable digital transmission and receiving a bunch of coloured squares. Most digital receivers of today can NOT drive a polarizer. The Fibo-Box V3 and V4 can drive a polarizer.


This polarizer is handmade by a very handy member of the forum. The polarizer has a 5 volt servo motor and can turn the lnb approximately 50 degrees in steps of 0.5 degrees.