many SDRs can RX/TX spectrum many times wider than you think is required in here.

Try to look at this small enthusiast SDR receiver - http://g4wim.proxy.kiwisdr.com:8073/ / http://kiwisdr.com/public/ you can see that simple 350$ radio can have 100s of "channels" visible/receivable at once. (digital modes are available in bottom right "toolbar", in top right corner, drop menu called "extensions" )

so with (different) SDRs you no longer need to choose one channel and listen to it, you can receive 200 channels at once, storing that data and choose what channel you want to decode later

or decode multiple radio stations realtime at once, even each with different mode (AM/FM/Olivia/USB...) and you can even (UNIX) pipe data from it, to programs not designed for ham / sdr use. data is just data as soon as you have it you can do anything with it. you can even write program/script to send email/notification/sound when specified callsign makes call/connects to trunk. for billing purposes...

or BTS/repeater can listen to 50Mhz wide part of spectrum 400Mhz-450Mhz AT ONCE realtime so no "tuning" necessary. for example 2000$ USRP can do that (but you need amps, filters etc to make full BTS )