Sat feed Question

[Tim B]

I have a dual C-band feed horn on a 4.5M dish. I am getting 2 wide white bars in the video that roll vertically slowly on the V feed. The H feed is fine. My first thought was a receiver issue, I changed the feed to another unit and the problem followed. Next I changed the LNB and the problem remained. I rotatated the feed horn and no help. I did find a cut in the RG-11 so I pulled in a new cable and the problem remains. I am out of ideas, outside from changing out the feed horn. Could this be caused by the feed horn? There is a crack in the RF window.

[NECRAT]

I am going to assume you're talking about an analog feed.

I am going to take a guess what you have isn't related to the LNB assembly or the dish at all, but rather some sort of bad TI. But before I even get to that point, have you tried doing a complete swap on the cables? What I mean is this...

Excuse my text drawing here...
DISH -- CABLE -- RX
H) ----<cable 1>---- (H
V) ----<cable 2>---- (V

Swap cable 1 for cable 2, so H is going through the old V cable and V is going through the old H cable? If the noise changes to H, you got a cable issue. (Breach in the shield near some electric lines, etc)

If it is TI, then there are other things to start looking at. Smaller scale, are there any light poles near the dish? (parking lot lights), or is it aiming towards a traffic light on a utility pole. If you have a light pole near the dish, make sure the light pole's ground is still grounded well. Is it aiming near a motor somewhere, like a AC unit, etc?
On a larger scale, if none of that shows up, are you near an airport or military installation?

One thing to do also is to look on a spectrum analyzer at the feed and see what the noise looks like, you can tell a lot from that sometimes too.

[Tim B]

I found the problem, Thanks for the input , sometimes it just takes fresh eyes to look at the problem.

[NECRAT]

What ended up being the problem?

[Tim B]

I ends up my asst. added a extra LNB power injecter further down the line w/o telling me. He had no idea this would cause a problem with the receiver also provivding Power. once again it comes back to "what was the last thing you did?"