Viking VX 900 MHz LTR, User Manual

Page: 81 / 234

CIRCUIT DESCRIPTION
6-21
October 1999
Part No. 001-2009-201
Pin 30 RSSI
This pin is the Receive Signal Strength Indica-
tion to the Controller. This RSSI is used for tune-up of
the Receiver front-end during factory test mode. The
dynamic range is 60 dB. It has an output from an op-
amp with the voltage going from 0.5V to 4.5V. The
level has an adjustment in the Receiver.
Pin 31 GROUND
Pin 31 carries ground current between the RFIB
and Chassis Backplane.
Pins 32-36 UNUSED
6.6.3 FAN CONNECTOR (J104)
The outputs to the fan connectors are 4-pin plug-
in terminals that supply DC voltage. The plug on the
fan is a 2-pin connector. The plug-in terminals are
located on the back of the RFIB.
Pin 1 FAN 1 LOW
Pin 1 is the ground return for Fan 1.
Pin 2 FAN HI
Pin 2 carries the voltage to Fan 1. The current is
1/4A nominal at 20V to 30V. This pin goes high when
the PA heat sensor rises above 50
°
C and goes low
below 45
°
C.
Pin 3 FAN2 LO
Pin 3 is the ground return for Fan 2 in 160W
repeaters.
Pin 4 FAN HI
Pin 4 carries the voltage to Fan 2 in 160W repeat-
ers. The Voltage is 20V-30V at 1/4A nominal. Pin 4
goes high when the PA heat sensor rises above 50
°
C
and goes low below 45
°
C.
6.6.4 POWER AMPLIFIER CONNECTIONS
WO 115 POWER SENSE
This capacitive feedthrough pin is at +15V DC to
the Power Detect Board.
WO 116 +26.5V DC
This capacitive feedthrough pin is at +26.5V DC
and carries the PA current, 20A nominal at 160W from
P102 to the Power Amplifier board.
WO 117 +26.5V DC GROUND
This capacitive feedthrough pin carries ground
current from P105 to the Power Amplifier board. It
must be capable of carrying up to 25A.
WO 118 +15V DC
This capacitive feedthrough pin co15V
DC P103 to the PA, Exciter, and Forward/Reverse
Power Detect boards. Maximum current handling is
6A (4A nominal at 160W).
WO 119 NOT USED
WO 120 CTRL OUT
This capacitive feedthrough pin carries the out-
put of the power control driver on the RFIB to the
power control pin of the power module on the Power
Amplifier board. The voltage varies from 0V-15V
with current as high as 0.5A.
WO 121 FWD PWR
This capacitive feedthrough pin is the forward
power sense line. It is a voltage source that is a func-
tion of the output power of the Power Amplifier. The
voltage level will be between 0V-5V and drive a 10k
ohm load. A typical voltage of 3.9V correlates to
160W out of the PA. This line goes through the multi-
plexers and A D LEVEL line to the Controller for pro-
cessing.