"Jeff" wrote in message
How accurate are the larger dishes? Dish gain is dependant on accuracy of
the surface (as a fraction of wavelength). As the KU band has 1/3 the
wavelength, would most C band dishes be good enough? It's much easier to
make a small dish accurate than a large one.
So far as how accurate the dish itself is manufactured, I don't know. I have
always thought that the various size dishes would work fine for C or KU, but
C needs a larger dish, you can use a smaller dish for KU, and will get a
better signal with KU when using a larger dish.
I've not heard of a larger dish not working for KU, but have heard that you
will get better reception with a larger dish.
So far as accuracy of mounting the LNB/feedhorn on a dish, it is quite easy
on a small dish, but can be a pain on the large dishes which were used for C
band. Not a matter of just bolting these things on for the large dishes.
With a large dish, need to measure, adjust, etc. The feedhorn can be mounted
closer/further away from dish, or up, down, left, right a little. (Read and
So far as pointing the dish and accuracy, you are aiming at an object 30,000
miles away in space (satellite). It is somewhat easy when just pointing at
one satellite like with DirecTV, etc. But quite difficult with any size dish
which is motorized and can tilt to receive from many different satellites.
The arc needs to be just right, then up/down just right, then left/right. It
helps a whole lot to have a signal meter with a beeper on it. Then you can
keep moving the dish back and forth, making small adjustments until you get
the strongest signals on all satellites in the arc.
Took me about a week and a lot of patience the first time I did this, but I
sure had a lot of fun getting it just right. (I like a challenge!)