Thread: Trunking
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Old December 27th 05, 06:11 AM posted to rec.radio.scanner
Paul Hirose
 
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Default PRO-95 trunking

System Name: Radioland 900Mhz (Indiana)
Location: Floyds Knobs, IN
County: Floyd
System Type: Motorola Type II Smartzone

System Frequencies
Site Description Freqs
001 Site-1 936.6875 936.7125 936.7250 936.7375 936.7500 937.6375
937.6500 937.6625 937.6750 937.6875


First off, I have never programmed a PRO-95 in the 900 MHz range, but
it should go like this:

First pick a scanner bank that's empty or at least doesn't have
anything important. Load the above freqs as if they were conventional
channels. In my case, Bank 9 is free so I'd store them in channel 900,
901, etc. Now scan those channels and listen for the one that emits a
continuous data stream (buzz or roar). That's the control channel.
When the PRO-95 stops there, press MODE until the mode indicator in
the upper right part of the screen says MO. (Available choices are FM,
MO, ED, AM.) If the PRO-95 is reading the data ok, you'll see MOT:
CNTRL appear at the bottom of the screen. (If people are talking,
you'll also see their talkgroup numbers on the screen.) Lock out the
other channels you entered.

Press PGM then TRUNK. Then press MODE until MOT appears in the bottom
line of the screen. (Available choices are "not trunked", MOT, and
ED.) You'll see some other stuff on the screen; ignore it. MOT is the
important setting.

Finally press SCAN and you should be in business.

You could delete the other channels instead of locking them out, but I
wouldn't, since some systems rotate the control channel among the
assigned freqs. If you turn on the scanner some day and find the
control channel dead, it's probably been moved to one of those other
freqs.

Note that there's a difference between setting a *channel* to trunked
mode (described in my second paragraph) and setting a *bank* to
trunked mode (third paragraph). These are two independent things.

You can set a channel to trunked mode even if it's stored in a bank
that's not set for trunking. Why would you do that? Well, suppose you
have a freq that sounds like a trunked system control channel. For a
quick check, just store it in any free channel. Try setting the
channel to MO or ED mode as you watch the display. That'll immediately
reveal if it's carrying Motorola or EDACS trunking data. For this, the
bank's trunking setting doesn't matter.

It also doesn't matter if a channel is set to a non-trunked (FM or AM)
mode. Such a channel is scanned like a conventional channel,
regardless of the bank trunking setting. In theory a bunch of
conventional channels can share a bank with a trunked system. In
practice I have found that doesn't work so hot. There's no quick way
to focus the scanner on the trunked system if an incident is breaking
there. I have to keep punching the lockout button to silence the
conventional channels sharing the bank. Then later I must remember to
unlock them. The whole business is such a hassle that I don't share
banks, though it means several hundred channels aren't available for
conventional use.

A Motorola control freq doesn't have to be stored in the first
channel of a bank. There can even be more than one active control
channel in a bank. (You might set the scanner up that way if a trunked
system has more than one repeater site within receiving range.)
HOWEVER, the PRO-95 will lock onto only one control channel and ignore
any others in that bank.

With EDACS, I think the last 2 digits of the channel number in the
PRO-95 must match the LCN (the EDACS channel number). For example, the
freq for LCN 3 could be stored in scanner channel 103 or 203 etc., but
not in 153.

--
Paul Hirose
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