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COMPLETE ALIGNMENT
7 0 - 3 4 2 ~ ~ / 4 4 2 ~
RECEIVER ALIGNMENT
All
audio
measurements
in the following steps are taken
across
an
external
3.2 ohm,
1 0 watt resistor connected to pins
4
and
6
of
the
Power/Accessory
Plug
P393
(or the Power Plug
5391
on
trunk-mount
units)
in
place of the wire jumper in pins 5 and
6
.
The
internal
speaker will be disabled.
14.
Select Test Channel 3 (lowest test frequency).
Adjust L209 and
L210 for maximum DC voltage on Injection Metering Point CM202
pin
1.
15.
With Test Channel
3
selected, apply sufficient unmodulated, on-
channel RF signal to the antenna
connector to maintain
approximately 2 0 to 3 0 dB quieting.
Adjust L201, L202, L204,
L205, and L206 for maximum quieting indication (peak positive
voltage) at CM202 pin
2.
16.
Apply 1 mV of modulated (1 K H z tone, +/-3 K H z deviation) on-
channel RF signal to the 50-ohm antenna connector.
Adjust
-
DETECTOR L252 for maximum audio output.
17.
Apply enough modulated
(1
K H z tone, +/-3 K H z deviation) on-
channel carrier to maintain 12 to 15 dB SINAD.
Adjust L208 and
L251 for best SINAD.
18.
Apply 1 mV modulated (1 K H z tone, +/-3 K H z deviation) on-channel
carrier.
Readjust L208 and L251 for minimum receive audio
distortion.
NOTE: If a distortion analyzer is not available,
this step may be deleted--although distortion specifications may
not be met.
19.
Set the front panel SQUELCH control to maximum (full clockwise).
Set SQUELCH RANGE RV251 fully counterclockwise.
20.
Apply unmodulated on-channel RF signal to the 50-ohm antenna
connector at a level equal to the desired tight squelch
sensitivity (usually 1.5 microvolts).
Adjust SQUELCH RANGE RV251
clockwise just until squelch opens (audio on).
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