Specifications

4-8. Squelch Adjustment.
A.Tune the receiver to a compatible active channel. Presence of an Alarm indication and a CXR
ALM display may indicate one or more of the following conditions:
1) No carrier is being received.
2) Squelch adjusted improperly.
3) The carrier receiver is malfunctioning.
Whenever there is a CXR ALM (regardless of cause) there should be no audio output from the
receive channel with the alarm.
B.Squelch is factory set to operate if the incoming subcarrier amplitude drops below 25 mV p/p. If
you wish to adjust the squelch threshold for your unique receive site conditions, or if you are
using subcarrier levels of less than 50 mV p/p, proceed as follows:
1.If the CXR ALM is displayed, adjust SQUELCH counterclockwise until the Alarm
extinguishes.
2.With the Alarm off, adjust the SQUELCH clockwise until the Alarm just lights. This is the
receiver squelch threshold for a valid carrier.
3.Turn the transmit subcarrier OFF or tune the receiver to an unused channel (i.e. no
subcarrier within 600 kHz).
4.IMPORTANT - COUNT TURNS THIS STEP: Turn the SQUELCH counterclockwise
until the CXR ALM just extinguishes due to RF noise.
5.Turn the SQUELCH control clockwise one-half the number of turns counted in Step 4.
6.Return to an operating channel. The receiver is now adjusted to squelch at a level halfway
between the operating carrier and the RF noise floor.
455 Operation Manual Page 31 6/23/98