Car Stereos: wireless modulator, high power, fm modulator, fm transmitters

Question
I bought a plain old fm modulator from WAl-mart and it sucked... the sound quality couldn't compete with local stations and when it was audible it was with lots of static.

I since bought a wired fm modulator and just complain about hissing sound, but overall have better sound quality.

HOWEVER, the other day while driving on the freeway some driver had an LCD sign saying tune into this xx.x station...   and I did... and there was a customized message that he used to advertize technical services.

So what the hell, I buy a wireless modulator that couldn't make it to my own radio from within my car and had to get a wired one...  none the less this guy zooms buy I put the station on and even after he has quite a bit of distance I can still hear his broadcast..

So tell me, where do you get that kind of stuff?  whats that modulator called? who sells them? how much do they cost? are they portable?

Thanks

Answer
Hi Mike,

It's usually a case of getting what you paid for.  Most FM transmitters are in the $20-$60 range.  The one the other guy had was likely a fair bit more expensive than that.  Those types of transmitters with that kind of range are usually in the $500 range.  An example is the Decade MS-100, which takes RCA inputs, and requires AC power (so you'd need an inverter aswell.)

As for the hissing of your current wired one, it might be a case of ground looping.  If it runs on batteries, make sure it has a clean connection to the antenna wire, and if it runs on car DC, then ensure that its connection to the antenna is clean, as well as its ground connection to the car.

Good luck,
Justin