TM11-5895-846-14
(2) Alternate modem. Set up the controls on
NOTE
the alternate modem (the modem not used in the on-line
In step k above, one or more of the
status) as follows:
five downconverters was designated
(a) Place the MODE switch to the TEST
as spare. Select a spare unit to be
position.
tuned
below
the
transmitted
(b) Place all other switches as (1)(a)
frequency as outlined in the following
(1)(c) through (1)(j) above.
steps.
(3) IF patch panel (A2). Set up the panel for
(1) Place the POWER switch of the selected
the selected modem filter and upconverter to be used in
spare downconverters to ON and observe that the
the mode of operation.
POWER indicators are illuminated.
u. Rack 6, Data Patch Panel (A8). Set up the
(2) Tune the spare downconverters 725 MHz
panel to process the selected data circuits.
below the transmitter frequency.
v. Rack 8, COMM/VF Patch Panel (A25).
r.
Rack 2 or 3, Upconverter (A11 A12, A15 or
Operate and check as follows:
A16). Operate the selected spare upconverter and
(1) Set up the VF SELECTOR switches for
observe as follows:
the selected multiplexer (A13 or A29).
(1) Place the POWER switch to ON.
(2) Check the CHANNEL SELECTION
(2) Observe that the POWER indicator is
switches for the orderwire and teletype circuits.
illuminated.
w. Rack 7, TTY/LL COMM Patch Panel (A15).
(3) Place the TEST OSC switch to ON.
Set up the panel to patch through the selected circuits.
s. Rack 1, Downconverter (A2, A3, A4, A5, and/or
A6). Place the MONITOR selector switch to IF OUT and
3-10.
Alarm Monitor Safety Alert Check
observe meter reading of 35 to 45.
On the alarm monitor ignore any SYSTEM FAULT CSS
NOTE
and RSS fault indications. Check that the audible alarm
Ventilation
ports
(internal
and
FAULT switch is in the OFF position. There should be
external). Adjust the ventilation ports
no SAFETY ALERT indications.
as required to provide proper
WARNING
ventilation of the equipment (para. 3-
If any SAFETY ALERT indicators are
8).
illuminated the conditions must be
t.
Rack 5, Modems and IF Patch Panel (A2).
cleared. Check the conditions as
(1) Modem (A3 or A6). Set up the controls on
follows:
the selected modem as follows:
a. At the antenna the elevation safety switch
NOTE
should be set for minimum (0) elevation angle. (Refer
FAULT lamps will extinguish after a
to paragraph 3-17 below and see figure 3-22).
delay.
b. Check waveguide connections at the power
(a) Place the ALARM/RESET-OFF-ON
amplifier SHF output port and both ends of the flexible
switch to the ON position.
transmit waveguide at the antenna and shelter entry
(b) Place the MODE switch to the
ports.
OPERATE position.
(c) TRANSMIT/INPUT DATA RATE
3-11.
Tuning the Transmitter
thumb dials set to 1.5440 MB/S X. XXXX.
Assume transmitter group 1 or 2 is assigned to on-line
(d) Place the TRANSMIT/QPSK-BPSK
status and operating on a different frequency than set up
switch to the QPSK position.
in paragraph 3-9. Tune the associated power amplifier
(e) Place the RANSMIT/ENCODER/DIFF-
klystron and upconverter to the assigned transmit
OFF switch to the DIFF position.
frequency. Proceed as follows:
(f) Place the TRANSMIT/ENCODER/
a. On the associated power supply place the
EXT- OFF switch to the EXT position.
OPERATE-STANDBY switch to the STANDBY position.
(g) RECEIVE/CHANNELSYMBOLRATE
b. Position the transmit waveguide switch so that
thumb dials set to 1.5440 MB/S X.XXXX.
this transmitter group is terminated into the dummy load.
(h) Place the RECEIVE/QPSK-BPSK
c. On the associated power amplifier open the
switch to the QPSK position.
hinged KLYSTRON TUNE cover by loosening the five
(i) Place
the
RECEIVE/DIFF-OFF
captive screws.
switch to the DIFF position.
d. Rotate the FREQ calibration chart knob until
(j) Place the RECEIVE/EXT-OFF switch
the assigned transmit frequency is registered along the
to the EXT position.
window line (see fig. 3-17). For example, if the assigned
transmit frequency is 8225.0 MHz rotate the knob until
FREQ 8225 is alined on the window's crossline.
3-30
