Many of these comments seem to be based on the assumption that "there's no way that a radio station's gear is better than mine" . . . pure audiophile snobbery. I agree that the vast, vast majority of FM stations sound like pure dog-crap. But it's because of choice, they don't need to . . .
First, a good FM station has an engineer that oversees the maintaince of all the equipment, and performs regular performance tests of the entire chain. Many of these people are extraordinarily talented and knowledegable from a technical standpoint, and take enormous pride in their work. Most of them I've known do it because they're passionate about radio, NOT because there's good money in it. Which there isn't.
Second, the processing devices that most FM stations use as part of their "air chain" are amazingly powerful and precise instruments -- and usually set up in such a way as to completely destroy the sound quality. But occasionally, they're set up and adjusted by an engineer that really cares about sound quality, and they can REALLY sound very nice. These are frequently stations at the bottom of the dial, many times with engineers that are donating much of their time to support their local college or community station.
Third, I've experienced a LOT of broadcast gear that simply sounds GREAT. Fond memories are of an old Ampro console chocked-full of precision transformers and rotary stepped attenuators, heavy Broadcast Electronics turntables with SME III tonearms and Ortofon integrated armwand/cartridges, the Gates TE-3 stereo exciter, and the fabulous Orban Optimod 8100A compressor/processor. All of this gear is designed to last for many decades, under harsh conditions (environmental AND electrical), and have virtually zero downtime. To meet these goals, most of this equipment uses conservatively-rated, high-quality parts that are extremely rare in high-end audio.
And finally, there exists quite a bit of potential accuracy of the FM signal chain itself. I remember making a typical 2AM audio performance check through the entire chain (console, studio-to-transmitter links with dbx noise reduction, Optimod, composite generator, exciter, transmitter, and broadcast monitor) and routinely getting frequency response of +/- 0.5dB from 30 to 15,000, with S/N ratio of about -55dB relative to 100% modulation, and 40dB-ish channel separation. WAY better than ANY phono cartridge. And the nice thing about FM is that once a signal is strong enough to be "full-quieting", the only thing that degrades this performance is multipath, and the quality of the tuner.
