- Oct 20, 2005
Attached is a photo of a system I just put together. I have not tried it yet. Do you think it will work? I am going to test it on Intelsat 19, using a 3.8M offset.
I’m not sure I understand what it is you are trying to achieve... are you trying to do linear on one LNBF and circular on the other?
I don’t think that would work, as each port of the orthomode feed would get only one polarity.
Indeed, in this type of feedhorn, I think the LNB that is directly aligned with the feedhorn has its polarity set by the shape of the tube, as it transitions to rectangular. and if you look inside you see a little metal thing encased in plastic (that thing is really an antenna) that transports the other polarity signal to the second LNB opening.
As for the C/KU combo LNBFs, I had the opportunity to try one on an 8-foot dish, and all I could get was the strongest transponders, such as CGTN on 95W, and JBS on 99W. From what I understand it's basicaly a C-Band LNBF, and they made a hole at the end and mounted a Ku LNBF. But the built-in feedhorn is really tuned for C-Band and the Ku LNB gets limited signal. From what I read, it works fine on some dishes and really poorly on others.
Instead, on my 10-ft dish I attached a cheap Ku LNBF to the side of the C-Band scalar, and it's working quite well. Of course one drawback is that Ku- and C-Band are not aligned, so that's many more entries in the positionner. (I also added a circular polarization feedhorn on the opposite side of the scalar)
that's cool! Looks likely that you're getting the Canal Calédonie package that's aimed at New Caledonia and at Wallis and Futuna islands (just like we're getting Canal Caraibes from here).I tried the combined C/Ku feed and picked up the C-Band AFRTS encrypted transponder on the dateline Intelsat, but got no Ku. I decided to take the Ku LNB out of the combined unit and and try it on its own. I mounted the LNB in the C Band Feedhorn, at its focal point, so I could easily rotate it to the correct polarization. I got the strongest signal I have ever received here 13.7 C/N. I attached a cable and did a blind scan and picked up 64 Ku TV channels. I think they were all French and most were encrypted. Tomorrow I want to try the same Ku LNB at the focal point of my offset 3.8M dish on Intelsat 19. The photo shows the Ku LNB mounted with packing foam inside the offset scalar feed, ready for the test.