Quote:
|
Originally Posted by elgemcdlf
Ok next on the list of do's  I am assuming you know that the cast 90 is for the Ku lnb and the bolt on is for the C lnb. If you have this reversed fix that. Next remove the bolt on 90 and bolt the C band lnb directly to the feedhorn. Roughly a 3db gain. |
I've read posts from people who say that you lose some signal in the waveguide, and I often discard the elbow waveguide myself, but I really find it hard to beleive that you'd lose 3db of signal there, unless it was installed wrong. I may be wrong, and don't have any scientific data, but I've used them with and without the elbow and never noticed a difference in signal strength, so I'd be really surprised if you'd lose this much signal.
I used to do research at microwave freqs, and we used wave-guides that were quite long (feet) with elbows, and we didn't lose any noticeable amount of signal. Just make sure that the connections are tight, because microwave tends to travel along the surface skin of the metal , and you get loss where there are discontinuities.
Anyway, I'd say that if it helps make the feed fit inside a cover, or even if it keeps the lnbs from sticking out and blocking incoming signal, then leave the elbow on there, however if your lnb is a shorty version, it's often more convenient to take the elbow off.