3
6
3
7.
If the REFL RF POWER meter registers more than 10% returned power, all the components
in the RF system (i.e., transmission line, antenna, jumpers) after the transmitter’s output
should be checked thoroughly for higher than normal VSWR. The offending component
should be repaired or replaced. If the output VSWR seen by the transmitter creates more
than 25% returned power, then the VSWR overload protection circuit will place the unit in
standby.
3.3b
EMEX1 Exciter Drawer Indicators:
1.
Under normal “on the air” operating conditions the Exciter’s green LED indicators should
appear as follows:
SYNTHESIZER LOCK
6
on
IF STATUS
6
on
AMPLIFIER STATUS
6
on
LINEARITY CORRECTOR
6
on
AGC ACTIVE
6
on
SWEEP MODE
6
off
OPERATE/STANDBY
6
on
VSWR RESET
6
off
AGC voltmeter
6
1 segment lit at approximate center
RF POWER meter
6
100%
2.
An extinguished SYNTHESIZER LOCK light indicates that the UHF Synthesizer (A2A2) is
defective and should be replaced. Under this condition the transmitter is placed in
permanent standby until the problem is resolved.
3.
The IF STATUS indicator provides verification that an IF signal of appropriate amplitude
and frequency is present at the Exciter’s input. Loss of IF input from the modulator will
cause this LED to shut off.
4.
The AMPLIFIER STATUS indicator monitors the operation of the 2 Watt UHF Amplifier
module (A2A1) within the Exciter drawer. With the amplifier operating normally, the
indicator will be lit green. However, if one of the transistors within the module fails, this LED
will extinguish.
5.
The LINEARITY CORRECTOR LED, when lit, indicates that the corrector is active. This
function is manually controlled by the ENABLE/BYPASS switch (A2PC2S1) mounted on the
corrector PC board. This indicator will turn off when the corrector switch is placed in
BYPASS.
6.
The AGC ACTIVE light will be lit when the front panel AGC/MANUAL switch (A2PC3S2) is
pressed in engaging the transmitter’s output automatic gain control. With the front panel
switch placed in MANUAL (released/out), the AGC is disengaged and the LED will go out.
7.
The SWEEP MODE LED will typically be turned off and is only active when the OPERATE/
SWEEP switch (A2PC4S1) on the Control/Interface board is placed in the SWEEP position.
This position deactivates both input and output AGC circuits so that low level sweep
measurements can be made.
