On Fri, 17 Jul 2009 18:27:05 -0400, mm
wrote:

What voltage is meant to be used by 18 inch satellite dishes?
AC or DC?

DC. For simple LNB's, 13V for left hand circular polarization. 18V
for right hand. That corresponds to the odd channels and the even
channels (or the reverse in case I got it backwards). If you're using
a DiSEqC switch, there's also a 22KHz control tone to switch outputs.
Life gets really complexicated if you have a 5 LNB dish.

I found a satellite antenna in the trash, and I dont have satellite,
but I saved the clip-on VHF/UHF antenna that goes around the edge. It
needs power but the only manual I can find says it uses the same
voltage as the dish, and doesn't say how much the dish uses.

Ugh. I don't know how the VHF/UHF antenna is switched.

Thanks for any help on all my questions.

P. S. I also took off the center part, the receiver or whatever, and
sold it for a dollar or two at a hamfest. They sell new for 50
dollars but tha's okay.

You can also build a wi-fi range extender with the dish:
http://www.findmorecollectibles.com/wifi.html
http://www.engadget.com/2005/11/15/how-to-build-a-wifi-biquad-dish-antenna/
http://www.qsl.net/ki7cx/wgfeed.htm
http://www.weijand.nl/wifi/