These (I'm told) will drive an antenna pretty well:
http://search.ebay.com/search/search...e=search&fgtp=
. Probably outside FCC guidelines, so I'm not officially recommending it...
The little UHF transmitter is adequate. More of a toy than a commecial product. I specifically wanted one UHF transmitter for my vintage sets that have UHF tuners (only 3 of them), so they would have at least one UHF signal to look at. The toy serves that purpose acceptably. It does have an RF-out coax port, so you can hook it up to better antennas. Perhaps that's how they got the 500-foot range out of it.