MAIN/STANDBY 125 WATT RADIOBEACON WITH NDDS/T
(INSTALLED
IN NARB07 CABINET)
IS02001 (Page 8)
29 January 2002
connector, using a suitable coaxial cable.
(c) Ensure the transmitters cannot be controlled
remotely. Set the
CONTROL
switch of both
transmitters to
LOCAL
.
(d) Turn on the transmitter to be tested/serviced.
Set its
POWER
switch to
ON
.
(e)
Test/service the transmitter using the procedures
in the ND500II 125 watt radiobeacon
transmitter instruction manual.
(f) On successful completion of maintenance
procedures, turn off the transmitter being
tested/serviced. Set its
POWER
switch to
OFF
.
(g) If required, repeat steps (d) thru (f) for the other
transmitter.
(h) When operation into an antenna system is to be
restored:
-
disconnect the dummy load's coaxial feed
cable from the cabinet's RF output
connector.
-
connect the antenna system's RF feed cable
to the cabinet's RF output connector.
-
Set
the
CONTROL
switch of both
transmitters to
LOCAL
or
REMOTE
as desired.
-
Select
the
main
transmitter. Set the
SELECT MAIN TX
switch to the desired
setting.
-
Turn on both transmitters. Set their
POWER
switches to
ON
.
7.2
WITH AN ON-AIR TRANSMITTER:
If one transmitter is to be operated into a precision
dummy load while the other is on-air, the standby
on/off control must be disabled and the RF outputs
must be reconfigured as follows:
7.2.1 Tx B Under Test/Tx A On-Air:
If the
B
transmitter is to be operated with its RF output into a
dummy load and the
A
transmitter is to be maintained
in an on-air status, proceed as follows:
(a)
Turn off the
B
transmitter. Set its
POWER
switch
to
OFF
.
CAUTION
Wire #13 and wire #38 have 15VDC on them when
their associated transmitter is turned on. Ensure
terminal lug, of either disconnected wire, does not
contact a conductive surface.
(b) Disable the standby on/off control for both
transmitters. Disconnect wire #38 from TB1-6
of the
A
transmitter and wire #13 from TB1-6 of
the
B
transmitter.
(c) Disconnect
the
B
transmitter's RF output coaxial
cable (wire #33 terminated by P1) from its RF
output connector.
(d) Connect a 250 Watt, precision, 50-ohm,
resistive, dummy load to the
B
transmitter's RF
output connector, using a suitable coaxial cable.
(e) Set or verify the
B
transmitter is set for local
control. Set its
CONTROL
switch to
LOCAL
.
(f)
Turn on the
B
transmitter. Set its
POWER
switch
to
ON
.
(g) Test/service the
B
transmitter using the
procedures in the ND500II 125 watt
radiobeacon transmitter instruction manual.
(h) On successful completion of maintenance
procedures, turn off the
B
transmitter. Set its
POWER
switch to
OFF
.
(i) If main/standby operation is to be restored
proceed to step (j). If the
A
transmitter is to be
tested, while transmitter
B
is maintained on-air,
proceed to paragraph 7.2.2.
(j) Disconnect dummy load's feed cable from
transmitter
B
's RF output connector.
