Service manual

INTRODUCTION
1-9
March 2000
Part No. 001-3139-502
NOTE 1: Two procedures are detailed for RDM and
RVM alignment. Procedure 1 requires a communica-
tions service monitor with signal generator and spec-
trum analyzer capabilities, a Transmission Test Set, and
a Multi-Net portable radio. Procedure 2 requires an RF
Signal Source capable of simultaneous internal (fre-
quency range of 10 Hz to 10 kHz) and external modula-
tion, two personnel, a Multi-Net/LTR Signaling
Encoder-Decoder (PN 023-3039-360), i.e. MED box,
two RF Signal Analyzers capable of measuring devia-
tion of an RF signal, and a Transmission Test Set.
NOTE 2: This audio deviation adjustment procedure
should be done first at the Main Receiver Site
. The main
receiver site is typically the site that is collocated at the
transmitter site and would have the Revert option in-
stalled. Once the levels are set at the Main Site, NO fur-
ther adjustment of U44 should be done. (See Procedure
1 Step 9 or Procedure 2 Step 12.) The remaining RVM
inputs will self-align using the 1200 Hz pilot tone that
is generated from the RDM as a reference. It is critical
that the pilot tone level leaving the RDM is set properly
since the RVM uses this level to make up for losses
through the links. If the RDM-Audio Link-RVM path at
the remaining receiver sites is functioning properly, au-
dio deviation tests done from these sites should be with-
in 0.2 to 0.3 kHz of the Main Receiver Site. Deviation
levels outside of this range may be caused by improper
setup of the RDM or RVM or poor audio response of the
remote site links.
PROCEDURE 1
Necessary equipment:
• RF Signal Source capable of internal modulation of
1 kHz tone.
• RF Signal Analyzer capable of measuring deviation
of an RF signal.
• Transmission Test Setup
• Multi-Net portable equipped with a DTMF keypad.
This test procedure can be used to verify system
performance, but is not
recommended for system
setup.
1. Bring up a dispatch call using a Multi-Net portable
equipped with a DTMF keypad.
2. Adjust a communications service monitor to the
RDM receiver frequency (transmit frequency of the
portable). Verify that the Low Speed Data Devia-
tion is approximately 1 kHz (800 Hz for 900 MHz
systems).
NOTE: This assumes that no audio or background
noise is being transmitted by the portable. Adjust the
portable per the product service manual if the deviation
is not correct.
3. Press and hold the "5" key on the portable. Verify
on the communications service monitor that the
measured deviation of the portable is now approxi-
mately 2.5 kHz (1.6 kHz for 900 MHz). Adjust the
portable per the product service manual if the devi-
ation is not correct. Release the "5" key on the por-
table and take down the call.
NOTE: 800 MHz radios - 1 kHz Low Speed Data and
1.5 kHz for the DTMF tone. 900 MHz systems - 800 Hz
Low Speed Data and 800 Hz for the DTMF tone.
4. Adjust the communications service monitor to the
transmitter site frequency (receive frequency of the
portable).
5. Bring up a dispatch call using a Multi-Net portable
equipped with a DTMF keypad.
6. Verify that the Low Speed Data deviation from the
transmitter site is approximately 1 kHz (800 Hz for
900 MHz).
NOTE: This assumes that no audio or background
noise from the portable is being received and then re-
transmitted.
7. If the Low Speed Data is not at 1 kHz (800 Hz for
900 MHz) of deviation, refer to the repeater service
manual for proper adjustment.
8. Press and hold the “5” key on the portable. Verify on
the communications service monitor that the mea-
sured deviation of the transmit site signal is now
approximately 2.5 kHz (1.6 kHz for 900 MHz).
Release the “5” key on the portable and take down
the call.