In Texas, we have the VRPS Vintage Radio & Phonograph Society in Dallas, as well as the AWA Antique Wireless Association in Houston. There are concerned more with radios than TV but TV is definitely included and that is the sort of thing leading to great TV finds. These clubs have monthly meetings and the VRPS always has a informal swap meet before. I believe guests are welcome free, except at the conventions, one must be a member as there are auctions a-plenty.
http://www.vrps.org/
(annual convention coming November 16-18)
http://antiquewireless.org/
(AWA 2012 WORLD CONVENTION AUGUST 21-25 2012)