EFJohnson 764X Speaker User Manual


 
INSTALLATION AND DISASSEMBLY
2-6
November 1998
Part No. 001-7600-001
1. Monitor the transmit signal with a communications
monitor. Set it for HPF = Off, LPF = 20 kHz, De-
emphasis = Off, and Level = (P-P)/2.
2. Select a channel near the center of the band and turn
a long tone on (see preceding “NOTE”) by pressing
the appropriate front panel key.
3. Adjust potentiometer R18 (DEV) on the module for
the following deviation:
25 kHz Channel Spacing - ±3.5 kHz
20 kHz Channel Spacing - ±2.8 kHz
12.5 kHz Channel Spacing - ±1.7 kHz
4. Check channels on each end of the operating band to
make sure deviation is within the following
limits. If not, repeat preceding adjustment.
25 kHz Channel Spacing - ±3.0 to 5.0 kHz
20 kHz Channel Spacing - ± 2.4 to 4.0 kHz
12.5 kHz Channel Spacing - ±1.5 to 2.5 kHz
NOTE: It is recommended that scanning not be used
with these options because in may cause part or all of
the tone burst to be missed.