General Information; Scope Of Manual; Transceiver Description; Part Number Breakdown - E.F. Johnson LTR-Net 7243 Service Manual

7.5vdc 1 and 4 watts part no. 242-7243-xxx

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Contents
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Table of Contents

1.1 SCOPE OF MANUAL

This service manual contains operation, program-

ming, alignment, and service information for the E.F.

™

Johnson 7243 LTR-Net

1.2 TRANSCEIVER DESCRIPTION

The 7243 LTR-Net portable transceiver operates

in the UHF 430-470 MHz frequency range. Power

output is selectable for low (1 watt) and high (4 watt)

levels.

A range of up to 16-100 systems are program-

mable, depending on the type and the number of

groups in each. Systems can be programmed for LTR-

Net, LTR, and conventional operation. Each system

can be programmed with up to 99 groups. Currently, all

transceivers have a telephone keypad and three

programmable option switches. Refer to Section 2.1

for more information on operating features.

1.3 PART NUMBER BREAKDOWN

The following is a breakdown of the part number

used to identify this transceiver.

242 - 72 x 3 - x x 3

Band

1 = VHF*

4 = UHF

8 = 800 MHz*

9 = 900 MHz*

Type

3 = High Tier, dual BW

Signaling

2 = LTR*

4 = Multi-Net*

5 = SMARTNET/SmartZone*

6 = LTR-Net

1.4 TRANSCEIVER IDENTIFICATION

The transceiver identification number is printed

on a label that is attached to the chassis. The following

information is contained in the identification number:

SECTION 1 GENERAL INFORMATION

portable transceiver.

Freq Range

0 = Full band (800/

900 MHz)*

1 = 400-440 MHz*

3 = 430-470 MHz

5 = 470-512 MHz*

These configurations are

currently not available.

Model

Revision

From P.N.

Letter

7243

Week No.

6 = LTR-Net

of Year

1.5 TRANSCEIVER TUNING

The field tuning procedure is described in

Section 5.

Table 1-1 7243 Portable Accessories

Accessory

Battery pack, nickel metal-hydride hi cap

Rapid charger base, single unit with

120 VAC power supply

Antenna, hybrid UHF

Belt clip

Extension Test Cable

Programming Accessories

LTR-Net 7243/98xx programming

software, CD

PCTune software and test code, CD

PCFlash soft. & LTR-Net op. code, CD

Remote Prog Interface (RPI)

Programming cable (RPI to xcvr)

DB9 F to DB9 M 6-ft cable

DB-25 M to DB-9 F 6-ft cable

DB-25 F to DB-9 M adapter

1.6 ACCESSORIES

The accessories available for this transceiver are

listed in Table 1-1. A brief description of some of

these accessories follows:

Extension Test Cable - This cable is required to

operate the transceiver when it has been opened to

access internal components. It reconnects the keypad/

display board to the audio/logic board.

Programming Hardware - The RPI provides the

interface between the programming computer and

1-1