Circular feed improvements!!!



My Satellite Setup
Looking for general FTA info
My Location
Hello folks,

As some of you who have seen my posts may know, I have been trying to improve my reception of NSS-5 with a 1.8 meter dish receiving a left hand circular feed in Guam. I hope my trial and error method of improving the signal strength may help others here who are trying to receive similar polarization from this sat and others. If this is commond knowledge, forgive my post but I could not find any info through my searches of the forums... I first tried to receive circular polarization using one of the fiberglass plates normally supplied with an LNBF. My LNBF was a 22 K PBI Turbo 1200, with a stability of 0.5khz. There were no slots so I simply hot glued the plate to the feedhorn cover, adjusted it and tried reception. I could not get anything above a signal quality of 35. I tried another LNBF (Pauxis model, 17 K, 2 mhz stability (!!!!) which did not have a plate but my wife's old cutting board supplied a teflon plate (teflon has great dielectric qualities) which took me well over an hour to sand to size. I still could not get anything over 38-39 for signal quality on my reciever (a cheap Chinese brand named Chieta, I do not recommend them...).
After a few beers (the neurons began operating properly), I tried glueing the fiberglass plate to the feedhorn cover (external side), thus giving me two plates, one internal, one external. I could not believe the results, signal quality over 45, excellent picture and stability (no pixelation, etc.). I am waiting for the proper plate (internal) from the local distributer and may try additional methods to improve the signal further, which I believe can be accomplished with a larger plate affixed to the front of the feedhorn.
The best part was I accomplished this with an older LNBF, which has poor stability (in my opinion, and I am a newbie so go ahead and hammer away...) so if you have a PLL unit, you could probably get much better results than I did. Needless to say, the wife is happy, which means the nagging will temporarily cease. If you have a smaller dish and are having a hell of a time receiving circular feed, I hope my advice helps. Many thanks to Rolfw for help when I was putting together my initial system!





Amo Amas Amant Admin
Staff member
My Satellite Setup
IDD CI24 ECONO MM Penta 1.20 Galaxy II
1.2Mtr Polar MTG yes it has been on the arc for 25 years and is now fixed on 13 East using two pairs of rusty molegrips. Unlike me they never groan but always perform.
My Location
Blackburn, Lancashire
Thanks for the pictures and informative post Garry. C band is quite rare round these parts as mostly ku band transmissions and equipment. Never the less it is nice to see someone experimenting, although again circular polarisation is also a rarity here we use horizontal and vertical polarisation. NSS 5 is 179 degrees and is thus the opposite side of the earth to where we are hence the reason you would not find any information on this forum as we cannot see it. :-doh! Let us know how you go on with the powervu stb though