500 WATT RADIOBEACON TRANSMITTER
ND2000A-02x-xx0
Page 5-25
15 January 2005
(d) An audio signal generator, with appropriate
clip-on test leads.
5.5.2
OPERATIONAL ADJUSTMENT PRE-
REQUISITES:
The following pre-requisites must be
completed before attempting operational adjustments:
(a) Verify functional test/adjustment procedures,
detailed in paragraph 5.3.2 through 5.3.20, have
been successfully completed.
(b) Connect or verify the transmitter's RF output
(J1) is connected to a properly tuned 50-ohm
antenna system rated at 1000 watts.
(c) Verify ac power source's voltage is within five
percent of mean RMS voltage used to select
primary winding taps of power transformers
A7T1/A8T1 in paragraph 3.9.4 and it has a
minimum power rating of 1200 volt-amperes.
(d) Verify the test equipment identified in
paragraph 5.5.1 is available.
(e)
Set
POWER-AC LINE
switch A6S1 to
OFF
.
(f) Set remaining switches to positions tabulated for
Test Setting
in table 4-1.
(g) Set
O/P POWER
potentiometer A4A2R48
(A5A2R48) fully counter clockwise.
(h) Set
TONE LEVEL
potentiometer A4A2R19
(A5A2R19) fully counter clockwise.
(i) Verify
RF MON
switch A9A2S1 is set to
position (
VOLT
or
CURR
) recorded in the
Established References
section of table 5-2.
5.5.3
TRANSMITTER TURN-ON:
Apply ac
power to the transmitter and verify the indicator
indications are normal at initial turn-on, as follows:
(a) Verify the requirements of paragraph 5.5.2 have
been completed.
(b) Turn on ac power at the service entrance.
(c) Set
POWER-AC LINE
switch A6S1 to
ON
.
(d)
DC SUPPLY
lamp A7DS2,
B-
lamp A2A9DS1,
DC
SUPPLY
lamp A8DS2,
B-
lamp A3A9DS1
shall turn on.
(e) Set
RF
switch to
ON
.
(f)
RF CURRENT-ALARM
lamp,
TX ON
lamp,
MONITOR-BYPASS
lamp and
CON24V
lamp A7DS1 shall turn on.
(g)
AUDIO LIMITER
lamp A4DS1 (A5DS1),
RF
DRIVE-ALARM
lamp A4DS2 (A5DS2) shall turn
on initially. After a delay of approximately five
seconds, lamps should turn off.
(h)
REMOTE CONTROL
,
MOD DRIVE-ALARM
A4DS3
(A5DS3),
SWR-ALARM
,
STANDBY-ALARM
and
SHUTDOWN-ALARM
lamps shall be off.
5.5.4
CARRIER LEVEL ADJUSTMENT:
Set the unmodulated RF output to the intended carrier
level as follows:
(a) Verify the requirements of paragraphs 5.5.2
through 5.5.3 have been completed.
(b)
Set switches as tabulated for
Test Setting
in
table 4-1.
(c) Set
TEST-Power/Mod
switch to
FWD PWR
.
(d) Set
RF
switch to
ON
.
(e) Adjust
O/P POWER
potentiometer A4A2R48
(A5A2R48) for a forward power indication, on
/
TEST-Power Mod
meter, that is the intended
carrier level.
(f)
RF Current Alarm
lamp shall turn off.
(g) Set
TEST-Power/Mod
switch to
REFL PWR
.
(h) Reflected power indication on
TEST-Power/Mod
meter shall be near zero watts.
(i)
SWR-ALARM
lamp shall remain off.
5.5.5
MODULATION
DEPTH
ADJUSTMENT:
Set the RF outputs modulation
envelope to the intended modulation depth as follows:
