Batdude, those captures you posted look like something is dreadfully wrong. No way that the sites are so badly tuned that the first harmonic is just 20 dB below carrier. If it were that bad then the FCC would have shut it down. Mastr III repeaters are cleaner than that. But even that doesn't really matter because they're using Mastr Vs in the system now, which most certainly can be assured to be delivering signals of sufficient purity that the first harmonic is easily 60 dB down or better. (Minimum standard for FCC type acceptance.) In fact the spec sheet says -70.
What are you using to capture those spectrums and has it been bench checked lately? Honestly those look like something that'd come out of a cheap SDR with all the selectivity and rejection performance of a bus full of nymphomaniacs.
I have spent MANY hours with a yagi antenna, watching the system sites using a Rohde & Schwarz FSEA 30 spectrum analyzer that met calibration specs, and cross-checked with a Tektronix 494AP, and never seen ANYTHING even remotely like those spectra.
Those spectra....I don't believe them. You've got intermod or receiver overload or a really cheap SDR there. Just flat out not buying it.
Yeah, I looked up the header stamps on those charts and it looks like you're using an SDR. Well, you might want to test that SDR using a good clean signal generator and verify its actual performance. I'm thinking it's kind of garbage-like at the moment. Now, granted, I expect a lot out of test equipment and spectrum analyzers. I've worked with some of the best stuff ever made and worked with it every day for seven straight years. I'm picky and critical. I've had equipment with a zero span noise floor under -160 dBm and signal generators with a 140 dB dynamic range. I will be critical of the perfomance of a cheap SDR.
As for when the Brevard system was installed, I remember clearly that when two Satellite Beach PD officers were killed on A1A by a drunk driver, I was at work that evening in Cocoa Beach and had to detour through the Atlantic Plaza around the scene. And I knew something had happened because I was listening in using a Motorola STX-821 with GPS 1.1 controller, scanning the site frequencies. ( This was before any trunking scanner or any surplus EDACS radios existed yet.) That was 1992. I believe the system became operational in 1989 or 1990.
My point is....don't use a cheap SDR to make a point based on a spectrum capture. If you are looking for a GOOD analyzer on the cheap, for 500 bucks or less get an Agilent 4406A transmitter tester which is a basic 3.5 GHz range spectrum analyzer (plus options) and it has a bandwidth resolution of 0.1 Hz at minimum span and a very clean low noise floor. (I don't recall that spec at the moment.)