![Nautel ND2000A-02x-xx0 Series Скачать руководство пользователя страница 101](http://html1.mh-extra.com/html/nautel/nd2000a-02x-xx0-series/nd2000a-02x-xx0-series_technical-instructions_3530251101.webp)
500 WATT RADIOBEACON TRANSMITTER
ND2000A-02x-xx0
Page 5-21
15 January 2005
(h) Set
TEST-Power/Mod
switch to
FWD PWR
.
(i)
TEST-Power/Mod
meter's forward power
indication shall be the intended carrier level.
(j) If necessary, adjust
FWD PWR CAL
potentiometer A10R79 until
TEST-Power/Mod
meter's forward power indication is precisely the
intended carrier level.
5.4.2.2 Reflected Power Reading:
Check the
accuracy of the reflected power indication of
TEST-
Power/Mod
meter as follows:
(a) Set switches as tabulated for
Test Setting
in
table 4-1.
(b) Set
RF
switch to
ON
.
(c) Set
TEST-Power/Mod
switch to
FWD PWR
.
(d) Verify the RF output's forward power is the
intended carrier level, as indicated by
TEST-
Power/Mod
meter's forward power indication.
(e) Set
RF
switch to
OFF
.
(f) Disconnect connector P13 from A9A2J1.
(g) Disconnect connector P14 from A9A2J2.
(h) Install connector P14 on A9A2J1.
(i) Connect a shorting clip across resistor
A4A2R44 (A5A2R44).
(j) Set
RF
switch to
ON
.
(k) Set
TEST-Power/Mod
switch to
REFL PWR
.
(l)
Test-Power/Mod
meter's indication shall be the
intended carrier level.
(m) If necessary, adjust
REFL PWR CAL
potentiometer A10R107 until
TEST-Power/ Mod
meter's forward power indication is precisely the
intended carrier level.
(n) Set
RF
switch to
OFF
.
(o) Disconnect connector P14 from A9A2J1 and
install it on A9A2J2.
(p) Remove shorting clip from resistor A4A2R44
(A5A2R44).
(q) Install connector P13 on A9A2J1.
5.4.3
LOW AC VOLTAGE THRESHOLD
ADJUSTMENT:
Adjust the low ac voltage threshold
circuit as follows:
NOTE
When dc option is installed and the ac power source
voltage falls below the low ac voltage threshold,
BATTERY-ALARM
lamp will turn on. The transmitter's
RF output will remain at the intended carrier level.
When dc option is not installed and the ac power
source voltage falls below the low ac voltage
threshold,
SWR-ALARM
lamp will turn on. The RF
output will cutback to approximately 55 watts.
(a) Switch off the ac power source at the service
entrance.
(b) Connect the output of a variable power
transformer (variac) as the transmitter's ac
power source.
(c) Connect an ac voltmeter across the output
terminals of the variac.
(d) Verify the transmitter's output is terminated into
a 50-ohm load (properly matched antenna
system or a dummy load).
(e) Adjust variac's output for an ac voltmeter
indication that is the low ac supply voltage
(RMS) end for power transformer taps selected
in paragraph 3.9.4.
(f) Set switches as tabulated for
Test Setting
in
table 4-1.
(g) Set
POWER-AC LINE
switch A8S1 (A7S1) of
power supply module
B
(
A
) to
OFF
.
(h) Set
RF
switch to
ON
.
(i) Verify the transmitter's RF output is the
intended carrier level, as indicated by the
dummy load's forward power indication.
(j) If
necessary,
adjust
O/P POWER
potentiometer
A4A2R48 (A5A2R48) to set transmitter's RF
output to the intended carrier level.