Visuals will help...
Hey, almalo....I had a little time, so I looked around some......if you go to eBxx and Amazon, and put into the search window... "AR wireless speakers".....then put in RCA WS, and Advent WS......You should see some pictures of the transmitter units.....
They are small, and come in a couple of shapes....one I see a lot of is the Recoton/AR type....It's a little box, about 4" X 4" with a "flying saucer" on a pedestal on top ......The saucer can move up and down a little bit....it's the antenna part, I reckon.....Some AR units are more like a hockey puck with a slice taken off the back, where a short, stubby antenna flips up for use......
All these are marked pretty well....some have a pair of RCA jacks for stereo input, some use a 1/8" stereo jack for input...... as long as you see stereo in, and 900 mHz on it, you can use it for your application....
Not all of these, if any, offer really great reception( I'm talking super Hi-Fi, here).....but they will put out a decent signal that should work for rear channel use.........effective range is a crapshoot....all you can do is hook it up and see what happens... in most home settings, it should work just fine.....
I would not spend a lot of dough on this setup....really, at a garage sale or resale shop, less than 5 can get you in.....
Good Luck, let us know.............willhowl:yes: