There is a way to ID a translator without saying it on air. I have never personally seen the "frequently shift box" installed but apparently it's legal. I just wonder if is cost effective. Vocal IDs are free, except for paying someone for the less than 10 minutes to record and digitally speed it up to auctioneer speed. Most production folks are there any way hopefully recording or dubing many many commercials.
Frequency shift keying... heres the box, cheap (found a used a used one on ebay for $25)
