I decided i need to digress a bit. Here is my situation. I have a 10 foot button hook cband dish, my first, and its performance is sub optimal and I'm trying to figure out WHY? - I believe it has something to do with the LNBF and its alignment. Visually, it looks like it might be a bit offset. I am thinking i got into a situation of chasing the fine tuning in the wrong way.
Let me run something through my head to you guys. If i have the lnbf mis-aligned, then fine tuning the main dish to a signal would then fine tune me to a false max. Is this true? It seems to me that maybe i have to somehow better align the LNBF before then attempting to fine tune on the dish, other wise, I'm chasing a false max. Does that make sense..
I guess, I'm trying to get back to the basics.... How do wipe away any doubt that I am not fine tuning this dish correctly so that i can obtain the best signal possible. This is not a ARC tracking issue. I am tracking the ARC fine, but, i seem to be equally sub par on many TPs through out the ARC. TP's that I remember once not having issues with.
I appreciate the input....
I worked on a few button hook feeds where the tubing used to make them should have been heavier, leaving them drooping a bit.
This misalignment can be corrected by attaching a small diameter piece of aircraft cable 90 degrees apart around the dish, attached to the scalar on one end, the dish at the other, with a small turnbuckle in between.
It also allows for small adjustments on the focal point. I posted a photo of a tool I made on the lathe that went into the feed throat about an inch containing a laser I purchased off EBay.
I machined a hole in it at center, that was a few thousandths under the outside diameter of the laser body to hold it securely in place. It simplified setting the feed to dead center on the dish.
It can also be used to see if the feed is canted to one side or the other. I stuck a piece of duct tape over the center hole in the dish so you could see the laser. I know it sounds a bit overkill, but when you have 8 dishes, it's a handy tool.
If the string test is OK, you should be OK with the cables and turnbuckle, even without a laser tool.
