Audio/Video/Remote Panel Interface (A8J1)
Jack – Pin #
Function
2
6
34
FORWARD POWER INPUT J6-5. The output voltage of U5A is also used to
provide a reading on the Control/Metering RF POWER bar graph meter through
the FWD/REFL front panel switch S1. For further explanation see J5-7 below.
J4 – 2
AGC VOLTAGE: This is the same voltage that drives the AGC meter
(A2PC3DS12) located on the front panel of the Exciter drawer. This potential,
a representation of the IF/Converter output AGC voltage, is taken from Control/
Interface amplifier A2PC4U8B and made available for monitoring at REMOTE
jack A8J1-2 via A2PC4J5-4 and J5-4.
J4 – 6
REMOTE VSWR RESET: This input control originates at REMOTE jack A8J1-6,
loops through J5-5 to the Exciter Control/Interface input A2PC4J5-5 and on to
VSWR overload flip-flop reset pin A2PC4U9A-4. A momentary ground would
normally be applied to this line bringing the transmitter out of standby due to a
VSWR overload created by excessive returned power at the output of the unit.
(A momentary ground is also provided by Exciter front panel VSWR RESET
switch A2PC3S3.) The transition from high to low on pin 4 of flip-flop
A2PC4U9A will reset pins 5 & 6 to their original Q (high) and Q NOT (low) states,
removing the low from A2PC4U2D-13 and the high from VSWR OVERLOAD
LED control transistor A2PC3Q8, respectively. Exciter front panel LED
A2PC3DS8 will then turn off and IF input attenuator A2PC1CR7/CR8 will be
returned to normal operating levels.
J4 – 7
REMOTE AGC ON/OFF: This input control begins at REMOTE jack A8J1-7
and, by applying a ground, this pin can be used to deactivate the voltage that
controls IF/Converter output AGC attenuator A2PC1CR9/CR10. From J4-7, this
ground will be looped through J5-6 and sent to A2PC4J5-6. The low now found
at A2PC4U4D-12 will force A2PC4U4C-8 and A2PC4J8-10 low driving the
IF/Converter PIN diodes A2PC1CR9/CR10 to stabilize at the center of their
attenuation range (
3dB). With the output of A2PC4U4C at a logic low, that sig-
nal is also sent to pin A2PC4J10-18 and on to front panel AGC ACTIVE LED
A2PC3DS6. Since the voltage at A2PC3J1-18 is low, A2PC3Q6 will not conduct
and A2PC3DS6 will not illuminate indicating an inactive output AGC.
J4 – 5
REMOTE OP/STBY: This pin is connected to the Video/Audio/Remote panel
plug A8J1-5 which is normally left open allowing the high to remain at J5-1,
A2PC4J5-1 and A2PC4U1D-13 keeping the transmitter in operation. If the oper-
ator wishes to place the Exciter and transmitter in standby from a remote
location, a ground is applied to this line forcing output A2PC4U1D-11 to go low,
causing succeeding AND gates A2PC4U1B through A2PC4U2A to send a low to
the input of A2PC4U8A-3 and output A2PC4J4-3. The low forwarded to
A2PC4J10-21 will eventually enter the IF/Converter at A2PC1-7 via A2PC4J8-7
causing buffer A2PC1U9 to set IF attenuator A2PC1CR7/CR8 to maximum
attenuation preventing the Exciter from radiating a signal. Concurrently, the low
at A2PC4J4-3 will appear at J3-3 forcing U3 to shut down the 500W Power
Amplifier drawer power supplies (A3PS1/PS2). The transmitter is now in standby
prevented from radiating a signal.
J4 – 8
GND: From J7-4