Service manual

1-1
Month 2000
Part No. 001-2004-601
INTRODUCTION AND OPERATION
SECTION 1 INTRODUCTION AND OPERATION
1.1 SCOPE OF MANUAL
This service manual provides installation, opera-
tion, programming, service, and alignment informa-
tion for the VIKING
®
VX LTR-Net
®
Repeater, Part
No. 242-20X4-613.
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:
Figure 1-1 REPEATER IDENTIFICATION
1.3 MODEL NUMBER BREAKDOWN
The following breakdown shows the part num-
ber scheme used for the Viking VX.
Figure 1-2 PART NUMBER BREAKDOWN
1.4 REPEATER DESCRIPTION
The VIKING VX repeater is designed for opera-
tion in a LTR-Net and LTR system. It operates on the
UHF channels from 380-520 MHz. Channel spacing
is 12.5 kHz and RF power output is adjustable from 25
to 110 watts.
20X4X
Week Year A= Waseca
Number
Warranty
Plant
Date
Manufacture
Letter
Revision
12345A324A
Repeater
ID
3
242- 2 0 X
4-
UHF
1
12.5/25 kHz
6
LTR-Net
3 = 25-110W
3 = 400-430 MHz
4 = 430-470 MHz
5 = 475-512 MHz
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.
023-9998-459.
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
frequency pairs are assigned to radios and base sta-
tions in the system for use as a trunk group". Trunk-
ing is the pooling of radio channels where all users
have automatic access to all channels reducing waiting
time and increasing channel capacity for a given qual-
ity of service.
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-NET TRUNKED SYSTEM
LTR-Net repeater operation is automatic and is
similar to a LTR repeater in which a logic module per-
forms the call functions and communicates 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 information with all other
repeaters in the system via inter-repeater communica-
tion.
System control is accomplished by the exchange
of data messages between radio and repeater. The
LTR-Net system trunks up to 20 channels by utilizing
continuous subaudible digital data applied to the RF
carrier simultaneously with voice modulation. There-
fore, no dedicated control channel is required and all
channels are used for voice communications for maxi-