13
Alignment
FM Squelch Tight Adjustment
Connect the Radio Tester to the antenna jack, then
adjust the output level to +10 dBµV (with a standard
FM modulation: ±3kHz deviation @ 1 kHz) at 163.275
MHz.
Store Weather Channel ”WX-010” into a ”regular”
memory channel, per the instructions in the box on
the previous page.
Recall the memory channel into which you just stored
Weather Channel ”WX-010” in the previous step, then
turn the radio off.
Press and hold in the
PTT
switch,
MONITOR
switch,
and
VOLUME
knob while turning the transceiver on
to enter the alignment mode.
Rotate the
DIAL
selector knob to select “
04 FMTI xx
.”
Press the
VOLUME
knob twice.
Turn the transceiver off.
AM Squelch Hysteresis Adjustment
Press and hold in the
PTT
switch,
MONITOR
switch,
and
VOLUME
knob while turning the transceiver on
to enter the alignment mode.
Rotate the
DIAL
selector knob to select “
05 AMHS xx
.”
Press the
VOLUME
knob momentarily, then adjust the
hysteresis level using the
DIAL
selector knob.
Press the
VOLUME
knob again.
Turn the transceiver off.
FM Squelch Hysteresis Adjustment
Press and hold in the
PTT
switch,
MONITOR
switch,
and
VOLUME
knob while turning the transceiver on
to enter the alignment mode.
Rotate the
DIAL
selector knob to select “
06 FMHS xx
.”
Press the
VOLUME
knob momentarily, then adjust the
hysteresis level using the
DIAL
selector knob.
Press the
VOLUME
knob again.
Turn the transceiver off.
Transmitter Section
TX Power Adjustment
Connect the wattmeter and dummy load to the an-
tenna jack, then set the transceiver to 128.000 MHz
and turn the transceiver off.
Press and hold in the
PTT
switch,
MONITOR
switch,
and
VOLUME
knob while turning the transceiver on
to enter the alignment mode.
Rotate the
DIAL
selector knob to select “
07 TX PO xxx
.”
Press the
PTT
switch with no microphone input, and
confirm the RF output power is 1.5 Watts.
If not,
1. press the
VOLUME
knob momentarily,
2. rotate the
DIAL
selector knob clockwise (increase
the power) or counter-clockwise (decrease the
power),
3. press the
VOLUME
knob again,
4. confirm the RF output power.
Repeat above steps 1 - 4, so that the RF output power
is 1.5 Watts.
Turn the transceiver off.
TX Modulation Adjustment
Connect the Radio Tester to the antenna jack, then
adjust the AF generator output level for injection of
200 mV rms @ 1 kHz to the MIC jack.
Set the transceiver to 127.500 MHz and turn the trans-
ceiver off.
Press and hold in the
PTT
switch,
MONITOR
switch,
and
VOLUME
knob while turning the transceiver on
to enter the alignment mode.
Rotate the
DIAL
selector knob to select “
08 MDLV xxx
.”
Press the
PTT
switch, and confirm the modulation
level is 85 % (±5 %).
If not,
1. press the
VOLUME
knob momentarily,
2. rotate the
DIAL
selector knob clockwise (increase
the MIC gain) or counter-clockwise (decrease the
MIC gain),
3. press the
VOLUME
knob again,
4. confirm the modulation level.
Repeat above steps 1 - 4, to ensure that the modula-
tion level is 85 % (±5 %).
Turn the transceiver off.
Summary of Contents for VXA-300 Pilot III
Page 4: ...4 Exploded View Miscellaneous Parts ...
Page 5: ...5 Block Diagram ...
Page 6: ...6 Block Diagram Note ...
Page 10: ...10 Circuit Description Note ...
Page 16: ...16 MAIN Unit Note ...
Page 31: ...31 ...