I apologize if this has been covered in depth before; I have searched the site.
I am new to the site and have been searching this forum, googling the net, surfing eBay, Amazon, etc and have not yet figured out if anyone makes decent quality, part 15 compliant equipment that would meet my needs.
My use case is small outdoor events, like car shows. I'd like to find an FM transmitter that can operate on 12v in a car, where the other cars at a show can tune their radios to the same freq and we can broadcast lower volume music and announcements for nice ambiance at events, as opposed to a pair of loud DJ speakers blaring into the crowd. Similarly, we could strategically place various inexpensive FM receivers (boomboxes, etc) for an amusment park-like distribution of the audio. This would be less expensive than wifi transmitters and high-end portable speaker systems.
I would prefer stereo, in case we ever have a desire to actually place speakers to effect stereo sound, but I realize that scattered speakers/car radios defeat the purpose of stereo. I also know you take a big signal to noise ratio hit with stereo and lose range...so I am considering mono. (Maybe something out there is switchable?)
However, try as I might, I cannot find a transmitter (say, under $150) that is part 15-compliant AND is more than just a local FM modulator for in-car use. All the transmitters I have found on Amazon, eBay, etc in that price range, down to about $50 are of the "very shady" variety, with a "low power" mode that is "recommended for FCC compliance" but turn out to be WAY too low in the reviews. Or they are 1 watt or some other ridiculously high output. Or they bleed across a range a frequencies or cause noise and interference in the closest receivers. I am talking about stff from Fail-Safe, FMUser, CZH, Signstek, etc. They look ideal, until you look at the details/reviews.
Are there any decent quality manufacturers of 12v powered transmitters that actually provide a "max legal" signal strength, with clean signals, so I can get a range of a couple hundred feet? Without spending $200 or more ?
A friend who knows such things recommended this mono unit: http://www.progressive-concepts.com/products/Mono-ACC100-FM-Transmitter-... which is at the max of the budget. Is there anything else I should consider ?
Any advice is appreciated!