Vector-LP Radio Beacon Transmitter Technical Instruction Manual Page 4-7
Section 4 Testing and Adjustment Issue 1.1
(j) If the requirements of step (i) are not
met, set the transmitter to operate in
BYPASS mode. Press Reset in the
Status menu. The transmitter should
switch back to the main side and the
Changeover LED should no longer
be on.
(k) Decrease the modulation depth
(Keying Pot level) to 60%. Select Main
Menu/Settings/Monitor Settings/Mod
% Thresholds. Press Continue to
proceed. Press Compute New
Thresholds to establish new monitor
modulation % thresholds. If a
modification is made, a screen
appears which prompts you to save
changes to EEPROM. Select Yes.
Increase the modulation depth to the
desired level. Set changeover mode
to NORMAL. Return to step (g).
(l) Select Main Menu/Peripherals/Keyer
Settings/Audio Levels.
(m) The modulation levels should be as
close to desired modulation without
distortion.
4.3.5.7 SETTING MOD DEPTH IN
BEACON MODE
Set the modulation depth in beacon (no
voice) mode as follows:
(a) Ensure there is no link between the
PRESS-TO-TALK terminal (TB1-12)
and GND (TB1-13) on the remote
interface PWB (A3).
(b) In the Keyer Modulation menu (see
3.6.13.1), set Modulation and Tone
Generator to ON and set Keyer to
OFF. Set the Tone Frequency to 400
Hz or 1020 Hz.
(c) In the Audio Levels menu (see
3.6.13.1), set Keying Pot to 0.
(d) Press RF On. Increase the
transmitter’s output to desired power.
(e) In the Audio Levels menu, while
monitoring the Mod %, increase the
Keying Pot value until the Mod % is as
desired. If the modulating signal begins
to distort, stop increasing mod depth.
(f) In the Keyer Modulation menu, set
Keyer to ON.
4.3.5.8 SETTING MOD DEPTH IN
BEACON AND VOICE MODE
Set the modulation depth in PTT (beacon
and voice) mode as follows:
(a) Adjust the audio limiter as described in
4.3.5.4. The audio generator should
remain connected.
(b) Assert Press–To-Talk. The status
screen should indicate press to talk.
NOTE
If the system is in normal mode, connect a
link between the PRESS-TO-TALK
terminal (TB1-12) and GND (TB1-13) on
the remote interface PWB (A3). If the
system is being used in phantom feed
mode, apply -15 V down the shield of the
audio signal (see 2.2.13).
(c) In the Keyer Modulation menu (see
3.6.13.1), set Modulation to ON and
set Keyer and Tone Generator to OFF.
(d) In the Audio Levels menu (see
3.6.13.1), set Voice Pot and Keying
Pot to 0.
(e) Press RF On. Increase the
transmitter’s output to rated power.
(f) In the Audio Levels menu, while
monitoring the Mod %, increase the
Voice Pot value until the Mod % is at
the desired depth. If the modulating
signal begins to distort, stop increasing
the modulation depth.
(g) Turn off the audio generator.
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