AR8000 TIP - Scanning Trunking Systems Use Select Scan

AR8000 TIP - Scanning Trunking Systems Use Select Scan

Post by Victor Heal » Mon, 15 Jan 1996 04:00:00

What do you think of scanning the 800 MHZ trunking systems used by the
police? Do you like it or hate it?

Cobb County GA and Atlanta GA have moved to the 800 MHZ bands in the
last year or so. My first reaction was oh no! Then I discovered that I
could pick up far more then previously because of the intelligence
found in the phone patches the commanders were always running using
their new radios. The downside is that there is a lot of 'crap' also
in some of those lengthy phone patches when they call their current
'lover'.  As Cobb County abandoned 6 70cm frequencies 3 low vhf  a
half dozen vhf frequencies for putting everything on a fif*** channel
TRS followed by local cities like Smyrna GA moving FIRE and POLICE to
the same system I realized that I could hear more action with far
fewer frequencies programmed into a radio then before. BUT it was
harder to follow a certain thing like a fire or a neat speed trap
because of the channel hopping nature of TRS.

I can not think of any other hand held scanner that is more suitable
for scanning the cellular type TRS bands then the AR8000 (AR8K).
What have I discovered about the AR8K that now makes it my preferred
receiver for the trs systems? The SELECT SCAN FEATURE.
Using this feature I can now comfortably follow the fires, drug busts,
and speed traps with an absolute minimum of irritation from unwanted
stuff.

Lets use the fif*** channel TRS for example even though this applies
to any size TRS. One channel is devoted to control, so we are only
listening to 14 channels. The control channel is tagged by the PASS
key so it will not be scanned. As I scan the rest I noticed that the
phone patchs only appear on two channels so these can be locked out by
PASS if desired. Now for just basically eavesdropping on the county
action it is ok to just let the scanner bounce around the remaining
active channels. One notices that the same related comms appear only
on certain channels. Usually I recognize the same voice or it may be
the  content that I notice like details of a fire dispatch. The speed
trap on the interstate I-285 I was following today appeared only on
channels C6,  C12, C14, C15 as programmed into my AR8000. Now on
virtually every other scanner made in order to follow only that speed
trap one would have to lock out all the remaining undesired channels
one by one. BUMMER! But on the AR8000 all one has to do is TAG the
channels for select scan. Then to hear basically only the speed trap
activate select scan. If something else pops up, one of my selected
channels was being used as part of the fire grouping, just twist the
top knob to move on. I was able to follow the action which was of
interest to  me since I was out driving perfectly. Now notice this. I
heard the laser officer ask one of the cars to switch to talk around
for a private chat. He wasn't in my selected grouping! No problem I
hit scan until I found them and I was able to follow them even though
he asked him to switch manually to still another channel. FLIP I had
them again. The conversation was about one of the women in the radio
control room back at HQ. If I was using any scanner with locked out
channels I would still be fumbling with the darn thing long after the
secret conversation was over. FUNC SELECT SCAN put me back at the
scene of the speed trap a second after this brief interlude as they
resumed the action.

Select scan is valuable because the scan list can be cleared
completely by a couple of key strokes and another list started by
tagging channels as they are heard. An incorrectly selected channel
can be individually dropped from the list. Since you are selecting
only a few channels the scan seems very fast as the list is repeated
many times per second. I find that I can clear the list and start a
new one on the fly very fast now. For example early today I heard on
WGST that there was a breaking story of a serious gas leak in GWINNETT
county which has another TRS system. Within minutes I had selected
each of the channels that had activity  relating to this event. Then
with SELECT SCAN I was able to follow everything until they
successfully clamped the line and let traffic flow again on a major
artery in NW Metro Atlanta. How do I know I have all the channels? If
I hear part of the conversation and then a channel switch and I don't
immediately hear it continue I check to see which channel I am missing
by hitting normal SCAN. SELECT SCAN also has the advantage of ordering
the channels in the actual pattern that the TRS system is using for
that channel grouping if you are careful as you tag each needed
channel.
Read back your list and look at the scan order as compared to the
physical order in the scanner!

SELECT SCAN is discussed on page 6, and pages 69 through 73 of the AOR
AR8000 users manual.

Another use for select scan is in traveling in an area that has a
duplex radio system which doesn't repeat the mobile. The state of
Alabama has such a system for the state police. Place the base and
mobile in your select scan list and as fast as the base drops carrier
and the mobile replies you have him. Any other scanner you would have
to scan through a bank of 20 to 100 frequencies to hear both sides of
the conversation. Some folks get around this by repeating the
frequencies often in memory but you don't have to waste memory like
this in the AR8000! Another way to accomplish the same thing manually
in the AR8000 is to place both frequencies in the dual mode vfo's but
you have to manually switch between each which I don't care for while
driving.

Victor Healey
Ki4je
http://www.redwaveradio.com/~vhealey/ar8000.homepage.html