Bud Jamison writes in a message to Martin Niemeyer
 BJ> Any Public Service agency that I know of that has used digital 
 BJ> trunking has had problems, and encryption is even worse in 
 BJ> regard to range and conversion 'clarity'.
For starters, every transmitter and receiver has to be very close to exactly 
on frequency for digital to work.  Think of it this way, the digital signal 
is almost a frequency shift keying between 2 frequencies - one on either side 
of the nominal carrier.  Detection works the other way - so that if the 
transmitter frequency doesn't closely match what the receiver expects, you 
lose the ability to detect one side of the signal or the other...
 
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