I'm pretty sure that the 436/536 has adjustable AGC and other audio related things like filters and level adjustments to balance digital and analog audio. They exists in HP1 for both analog and digital so no reason to think that Uniden haven't moved the firmware code over to the newer models.
The AGC are set very moderate in a 536 but you can easily hear it operate if you have some constant background sound in a transmission and then someone starts to speak. Or when testing with a signal generator. Generating a low level RF signal that have some noise and then slowly increase the level of a 1000Hz test tone will slowly lower the background noise until it is gone and only the test tone are heard.
Testing a scanner without AGC, like a UBC780, gives the opposite reaction, the background noise increase together with the test tones modulation level. The BCT-15 has user adjustable settings of the different values of the AGC so it can be set to suit your own preferences. At first it was only factory adjustable and later it was accessed tru a button press combination and finally moved to the user menu. I don't know why Uniden are reluctant to have it as a user adjustable feature on all scanners. Maybe it's too confusing to must users and generates a lot of support inquires.
Whistler uses a much more aggresive AGC action. In some cases it works better and at other times it's incredible annoying with an irritating pumping audio action.
/Ubbe
