I use a pre-amp on a dedicated reciever for a specific service. The main trouble with pre-amps is that they are broadband. I am feeding the input from the antenna through a pair of tuned cavities then to the pre-amp. Typically I have better recieve than the service dispatcher.
Well Gary, what you have there is a preselector, not a preamp. By putting tuned circuits ahead of the active stage(s) you have mitigated the possibility of overload and intermodulation from strong unwanted signals, a feature notoriously absent in those DC to light preamps.
The bottom line here as it has been stated many times before, a broad band amplifier in an RF rich environment often creates more problems than it solves.