[Digiwave] Transponder help


SatelliteGuys Family
Apr 6, 2018
Ok need education again, so i know in ku tp's h is horizon ,v vertical.... But ir L left rotation, and R right rotation aka circular lnb?

Second picking up a 8 ft er c band for $20, can i add a c/ku lnb? Or switch to one.


Lifetime Supporter
May 23, 2013
Meadow Vista, Northern California
Horizontal and Vertical polarities are linear. Left and Right polarities are circular (think corkscrew). Often, one polarity type can be received adequately using a feed set-up to receive the other, but there will be approximately 3dB loss and the transponders will scan in on both polarities. In North America, FSS C-band and KU bands are transmitted using linear polarity. Circular KU is primarily used for subscription services and usually the LNBF frequency range covers upper KU 12.2 - 12.75GHz (with one exception on 118w).

A larger reflector may be able to receive KU if it is a solid metal or the perforations are small enough to appear to be RF reflective. The main problem with receiving KU on a larger reflector is that many reflectors do not have an accurate and smooth parabola. Much of the signal is lost as it is not focused into the feedhorn. Also, the beam width on KU frequencies with a large dish is so narrow that the dish aiming becomes very critical. Any slop in the mount or the actuator and the dish may not accurately land or move on/off during winds.
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