Mark Graves writes in a message to Ivy Iverson
 MG> I was thinking it was a trunked system too, but don't they 
 MG> usually have a control freq. or something similiar?
Trust me, you don't want to listen to the control channel!  It's a digital 
data stream.  However, some trunked systems will rotate their control channel 
among the first 4 channels of the system on a daily basis.  So the control 
channel today might have actual traffic on it tomorrow.  If you know 1 or 2 
of the freqs, try 1 MHz steps up and down.  For example, 851.1125 might imply 
other channels at 850.1125 or 852.1125.  Some trunked systems have licensed 
additional blocks of 5 frequencies so there might be steps of less than 1 MHz 
between blocks, but there are usually 1 MHz steps within the block.
 
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