Motorola Reception

Motorola Tracking

There are really two types of Motorola trunking systems.These are usually referred to as
TypeI and Type II systems. Type I only occurs on some 800 MHz systems. All VHF and
UHF trunking systems useType II.
One importantdistinction between these two systems is the amount of data transmitted by
each radio when itspush-to-talk button is pressed. Every radio in a trunked system is
assigned a unique ID so the central site computer can identify it when it’sused. Both Type I
andType II systems place radios (or radio users) into groups, called talkgroups, and these
talkgroupsare also assigned unique IDs. Some radios have access to only one talkgroup,
while others have access to many talkgroups.The talkgroup(s) each radio can access is
called the radio’saffiliation(s).
In aType II system, when someone uses their radio, only the radio ID is transmitted when
is pressed, whereas in aType I system the radio ID and its current affiliation are both
transmitted when is pressed.
Why the difference?Type II systems are slightly more advanced because the central
computer maintainsa database which is used to determine each radio’s affiliation(s).
Changes to aType II system are easier than Type I because the system manager only
needs to update the databaseinstead of reprogramming individual radios.
Another differencebetween the systems is that Type I systems are arranged in a Fleet-
Subfleet hierarchy.For example, its possible for a city using a Type I system to designate 4
Fleets,each with 8 Subfleets. Their fleets might be the Police Department, the Fire
Department,Utilities, and Administration. The Police may decide to further divide their fleet
into subfleetssuch as Dispatch, Tactical Operations, Detectives, North, South, East and
WestSide Patrols, and Supervisors. All the available police radios would then be assigned
to one of the police subfleets.Determining the exact Fleet-Subfleet hierarchy for a particular
area is referred to as Fleet Map Programming, which is discussed further in this manual.
The disadvantageof a Type I system is that when is pressed, the brief burst of data
must containthe radio’s ID and its Fleet and Subfleet. This is three times the amount of data
aType II system radio sends, and as a result Type I systems usually accommodate fewer
users thanType II systems.
Even though there are manyType II systems, Type I systems are still in use. There are also
Hybrid systems which are a combination of bothType I and Type II. Your scanner defaults
to monitorType II systems, but its possible to select a Preprogrammed Fleet Map or create
a Custom Fleet Map for your area.
For VHF and UHFType II trunking systems, you will need to know the base, spacing
frequencies and offsetchannels. See page 45 for details.
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