User Manual

SECTION 4
ALIGNMENT AND TROUBLESHOOTING
4-1
Part No. 001-2100-101
4.1 GENERAL
4.1.1 PERIODIC CHECKS
This module should be put on a regular maintenance schedule and an accurate performance record maintained.
Important checks are receiver sensitivity, transmitter frequency, modulation, and power output. It is recommended
that module performance be checked annually even though periodic checks are not required by the FCC. Section 4
outlines these tests.
4.1.2 SERVICING
The majority of the components used on the printed circuit boards are surface mount devices. JSLM
2
module
component level field repair is not recommended. Specialized training and equipment are required to service board
level components. Equipment should be returned to the factory for repair.
4.2 PERFORMANCE CHECKS
4.2.1 CHANNEL FREQUENCY
The module frequency is controlled by a temperature compensated crystal oscillator (DCXO) which has a
frequency stability of ± 1.5 parts per million over a temperature range of -30 to + 60° C. When transmitting (for
example) at 450 MHz, the output frequency should be 450 MHz ± 675 Hz over temperature. The operating
frequency may be adjusted through the case of the JSLM
2
. Connect the User Interface Cable included in the
JSLM
2
Field Programming Kit (part number: 250-2100-001). Connect the antenna port to a frequency counter or
other frequency measurement instrument. Locate the Frequency Adjust Access Hole on the bottom side of the
Loader Board (see Figure 4-2). Enable the transmitter PTT Line and use a small screwdriver to adjust the DCXO
for the desired transmit frequency.
Caution: An RF attentuator may be required depending on the power handling capability of the measuring
instrument.
4.2.2 RF OUTPUT POWER
The RF output power may be verified with an accurate power meter connected with a short 50 ohm cable to the
Antenna Connector. See Section 1, General Specifications for module specifications. Transmitter alignment is
performed in the factory and is not a recommended field adjustment.