Batboard

Okay, so I think I understand the concepts behind trunking systems, and the subscriber-side equipment (mobile/portable radios) are easy enough, but I'd like to know this (if it's been written up somewhere already, please just provide a pointsr--I have searched and not found it):

What does the (all-Motorola) infrastructure equipment look like for a small trunking system? Say three sites, and five or so frequencies per site.

I suppose you have to have radios--are these typically frequency agile, or fixed?--maybe antenna combiners, some sort of controller, and linking equipment to connect to the other antenna sites.

Is there a 'central' controller that runs the whole system?

The question is a little vague. Are you expecting Analog or Digital, 9600 or 3600?

Typical infrastructure has a Master site, which controls the other site's radio traffic.