Hello,

For those who are wondering what trunking is, it is a system where by the
frequency of a public service agency may shift.  In other words, the agency
has a group of frequencies within the 800 mhz band and they use them all, or
portions of them.  what this does to conventional scanners is that they will
never get both sides of the conversation because it begins on one frequency
in the group and ends on another.

There is a control channel keeping track of this for the system.  A trunking
scanner is capable of following the movements by tuning in to the control
channel.

This is probably not the best explanation for this but I think folks will
get the idea.  It would be similar to having a qso on the band while moving
your vfo up and down, the receiving station would need to move in the exact
sequence or they would never find you again.

Hope that helps, if anyone has a more thorough explanation go for it please.

73

de w2qcy