MAIN/STANDBY 125 WATT RADIOBEACON WITH NDDS/T
(INSTALLED
IN NARB07 CABINET)
IS02001 (Page 10)
29 January 2002
proceed to step (s). If the
B
transmitter is to be
tested, while transmitter
A
is maintained on-air,
go to paragraph 7.2.1.
(s) Connect
transmitter
B
's original RF output
coaxial cable (wire #33 terminated by P2) to its
RF output connector [it was disconnected in
step (c)].
(t) Select
the
main
transmitter. Set the
SELECT MAIN
TX
switch to the desired setting.
(u) Restore the installation to a main/standby
configuration by setting both transmitters'
POWER
switch to
ON
. Set the
CONTROL
switch of
both transmitters to
LOCAL
or
REMOTE
as desired.
7.3 AUTOMATIC CHANGEOVER CHECK
:
Check the changeover circuitry will automatically
select the
standby
transmitter, as the on-air
transmitter, when the
main
transmitter's RF output is
abnormal, as follows:
(a) Verify both transmitters are turned on and their
switches are set as specified for
Operating
Setting
in table 4-1 of the ND500II instruction
manual.
(b) Select
the
A
(upper) transmitter as the
main
transmitter. Set the cabinet's
SELECT MAIN TX
switch to
A
.
(c) Verify
the
A
(upper) transmitter is producing a
satisfactory RF output and the
B
(lower)
transmitter's RF output is inhibited.
(d) Disable
the
main
transmitter's audio keying (set
its
KEYING
switch to
OFF)
.
(e) After approximately 20 seconds, the
main
transmitter's RF output should turn off and it
should shut down. The
standby
transmitter
should be enabled as the on-air transmitter and
producing an RF output.
NOTE
If TB1-7 of the standby transmitter is connected to
ground, its 'standby 1' code variation will be
transmitted when it turns on.
(f)
Set the original
main
transmitter's
KEYING
switch
to
ON
.
(g) Restore the selected
main
transmitter as the on-
air transmitter by momentarily setting its
POWER
switch to
OFF
and then return it to
ON
.
(h) Verify
the
main
transmitter, as selected by the
SELECT MAIN TX
switch, is producing the desired
RF output and the
standby
transmitter's RF
output is inhibited.
(i)
If desired, select the
B
(lower) transmitter as the
main
transmitter. Set the cabinet's
SELECT MAIN
TX
switch to
B
.
(j) Verify
the
B
(lower) transmitter is producing a
satisfactory RF output and the
A
(upper)
transmitter's RF output is inhibited.
(k) Repeat steps (d) thru (h).
