User's Manual

3-6
3.4.2 Receiver Operation (Local Mode)
To operate the transceiver in the receive mode, proceed as follows:
(1) Ensure that the PRESS-TO-TALK switch on the microphone is NOT depressed, and
verify that the Tx ON amber LED is OFF.
(2) Verify that the correct operating frequency is indicated on the front panel.
(3) Adjust the SQUELCH control to suit local reception conditions. When the SQUELCH
control is rotated in the counter-clockwise direction, the SQUELCH
indicator green LED will switch to ON, indicating that the squelch circuit is
connecting the demodulated audio output to the VOLUME control.
Further adjustment of the SQUELCH control determines the squelch setting.
IMPORTANT NOTE
The dual conversion receiver’s squelch knob must be rotated significantly more
clockwise (4 o’clock position) to obtain the same squelch setting (3uV) as a single
conversion receiver’s squelch knob set to the 12 o’clock (straight up) position.
If the receiver’s squelch knob is set to the 12 o’clock position, signals with a level
greater than 0.5uV will open the squelch. At most airports this will not be an
adequate level of squelch.
Recommended procedure:
The squelch taper on a dual conversion receiver looks as follows:
Squelch knob position Squelch setting
12 o’clock 0.5uV
3 o’clock 1.2uV
3:30 position 2.5uV
4 o’clock 3uV
Fully clockwise 9uV
It is recommended that the squelch be set to at least 2.5uV (3:30 knob position) at
busy airport locations. If ACARS signals are present on adjacent or nearby channels
the squelch level should be at least 3uV (4 o’clock) to prevent ACARS bleed
through.
(4) The VOLUME control can then be adjusted in a clockwise direction to increase the
audio level, or in a counter-clockwise direction to decrease the audio level which
can be heard on the internal loudspeaker.
NOTE
When an external loudspeaker or headset is
connected to the SPEAKER/PHONE jack of the
transceiver, the internal loudspeaker is automatically
disconnected. The VOLUME control will now control
the audio level applied to the external loudspeaker or
headset, as applicable.