Just wondering if anyone has done this... I'm thinking that having the offset parabola configuration with the collector arm already in the right spot would make a quick spotlight build a little easier? Drawbacks?
Actually not too bad an idea. Main problem with satellite antennas is the focal point is often far enough away that you will only grab about 30 percent or so of the light from the bulb unless you yes LED which tends to send much of it's light forward, yet still much of the light will be wasted. Now with this said, my 50 inch Monster, my newest 36 inch searchlight plus lights like the big WWII carbon arc searchlights and many others that used this older style, telescope type configuration, make a very bright and impressive beam that at a far enough distance, the beam seems to show the bulbs full strength, even compared to other bulbs and searchlights using so called more efficient designs. The older style works well because of the focal length being so far, all the light hitting the reflector is going to go far, where much of the light on a deeper reflector like a car headlight, causes much of the light to reflect off parts of the reflector that are close in and so won't make as tight a beam. So, depending on the design of the dish, it may make a good surface to start, especially if it's already fairly smooth.
Good Luck and let me know how it turns out.
A
