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SECTION 1 INTRODUCTION AND OPERATION
1.1 SCOPE OF MANUAL
This service manual provides installation, opera-
tion, programming, service, and alignment information
®
for the VIKING
VX LTR
2009-232/234.
1.2 REPEATER IDENTIFICATION
The repeater identification number is printed on a
label that is affixed to the inside of the repeater cabi-
net. The following information is contained in that
number:
Repeater
Revision
Manufacture
ID
Letter
20XXX
A
Week
1.3 MODEL NUMBER BREAKDOWN
The following breakdown shows the part number
scheme used for the Viking VX.
242-200 9 -
2
3
X
9 = 900 MHz
1.4 REPEATER DESCRIPTION
The VIKING VX 900 MHz repeater is designed
for operation in a LTR system. It operates on the 900
MHz channels from 935-940 MHz (repeater trans-
mit). The repeater receive frequencies are 39 MHz
below these frequencies (896-901 MHz). Channel
spacing is 12.5 kHz and RF power output is adjust-
able from 25 to 75 watts (Part No. 242-2009-632) or
75-160W (Part No. 242-2009-634) with the high
power amplifier.
®
Repeater, Part No. 242-
Plant
Warranty
Date
Number
24
3
A
12345
Year
A= Waseca
2 = 25-75W
4 = 75-160W
3 = 12.5 kHz
VIKING VX
INTRODUCTION AND OPERATION
This repeater is modular in design for ease of ser-
vice. There are separate assemblies for the logic
,
cards, receiver
exciter, power amplifier and power
supply sections.
This repeater is programmed with a laptop or per-
sonal computer using the repeater software, Part No.
023-9998-297.
When the repeaters are installed in an environ-
ment that contains small airborne particles, e.g. grain
dust or salt fog, the repeater cabinets need to be
sealed. A heat exchanger, i.e. air conditioner, is then
required to cool the cabinets. The air conditioners
must be suited for the environment. Each low power
repeater (75W) requires >1200 BTU/hr dissipation to
maintain exterior cabinet temperature. Each high
power (160W or 175W) requires >2100 BTU/hr dissi-
pation to maintain exterior cabinet temperature.
1.4.1 TRUNKED SYSTEM
A trunked radio system, as defined by the FCC, is
a "method of operation in which a number of radio fre-
quency pairs are assigned to radios and base stations in
the system for use as a trunk group". Trunking is the
pooling of radio channels where all users have auto-
matic access to all channels reducing waiting time and
increasing channel capacity for a given quality of ser-
vice.
Trunking concepts are based on the theory that
individual subscribers use the system a small percent-
age of the time and that a large number of subscribers
will not try to use the system at the exact same time.
1.4.2 LTR TRUNKED SYSTEM
LTR repeater operation is automatic to where a
logic module performs the call functions and commu-
nicates over-the-air to subscriber units. There must be
one repeater for each RF channel and each repeater
contains a logic module responsible for signaling on
its own channel. Logic modules then share informa-
tion with all other repeaters in the system via inter-
repeater communication.
System control is accomplished by the exchange
of data messages between radio and repeater. The
LTR system trunks up to 20 channels by utilizing con-
tinuous subaudible digital data applied to the RF car-
1-1
October 1999
Part No. 001-2009-201
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