Viking 242-2009-632 - Manual (Page 142)

ALIGNMENT AND TEST PROCEDURES
7-14
March 1999
Part No. 001-2009-600
7.6 FULL REPEATER ALIGNMENT
7.6.1 PERFORMANCE TEST PROGRAM
1. Select the TEST - FULL REPEATER - ALL TEST
and press Enter.
7.6.2 REPEATER SETUP
The Viking VX repeater has been pretested at the
factory, therefore only performance tests are required
to check the repeater. Refer to test setup diagrams for
equipment and cabling diagram.
1. Pretest the MPC, IAC, MAC and RFIB per their
individual board level test procedures.
2. Pretest the Power Amplifier, Exciter, Receiver and
Chassis per their individual test procedures. The RF
modules should be tuned for the customer specified
T/R frequency pair. If not, retune per individual test
procedures.
3. Assemble the Transceiver to the Power Amplifier
and insert into the chassis along with the Power Sup-
ply, MPC and MAC. Slide the IAC partially into the
card rack but do not engage the locking level. Con-
nect the OCXO input to the high stability 1.25 MHz
source.
4. Engage the locking lever of the IAC and turn on the
repeater power supply switch (S508) in the IAC or
engage the locking lever (see Figure 7-30).
The operating code has been programmed at the
factory. The parameters are programmed into the
MPC. If these parameters have changed or are incor-
rect, exit this test and reprogram the repeater.
It may be necessary to remove the RF assembly
from the chassis and connect via extension cables for
some of the tests or adjustments.
NOTE: Unless specifically stated otherwise, all mea-
surements are to be done per the latest TIA docu-
mented procedures. All audio generators and audio
voltmeters are unbalanced unless specifically stated
otherwise.
7.6.3 TRANSMITTER TEST/ADJUSTMENTS
NOTE: 2000 Series OCXO must be powered up for 1/
2 hour or longer to stabilize frequency.
Transmit Mode
1. Use the "Turn on carrier" button to key the repeater.
2. The Transmit LED on the IAC should turn on to
indicate the repeater is transmitting.
3. Use the "Turn on carrier" button to unkey the
repeater.
Transmitter Output Power Test
1. Use the "Turn on carrier" button to key the repeater.
2. Check the transmit output power. The power can be
adjusted from the computer using the Power Control
button. Calibrate test equipment for
±
2W.
3. Use the "Turn on carrier" button to unkey the
repeater.
NOTE: This adjustment will alter the repeater’s stored
default value.
7.6.4 RECEIVER TESTS/ADJUSTMENT
Receiver TCXO Frequency Test
1. Check the receiver injection frequency by using a
"sniffer" pickup loop, or RF probe connected to a
suitable frequency counter placed near L210 in the
Receiver (see Section 7.2.4). The frequency should
be the Channel Frequency minus 52.95 MHz
(
±
90 Hz).
2. Tune Y201 (TCXO) on the Receiver at TP1 for 3.5V
DC
±
0.05V (response time is very slow).
Receiver Audio Distortion Measurement
1. Adjust the RF generator for 100
µ
V output with a 1
kHz tone at
±
1.5 kHz deviation.
2. Insert test cables into J100/J103 on the MAC and
connect to an AC voltmeter.