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3.3
Circuits for construction of the antenna simulator
are shown in Figures 4 through 6.
-"
~
}
NOTE
Figures 4 and 5 apply only for 23 to 60
foot antennas, whip or long wire.
P
l
..
900
UH
OHMS
=
.EPS'
3'000-0
Figure 4. Antenna Simulator Circuit for Models
TI959A, T1961A, T1962A (2-10.8 MHz)
1
ssp,
2 OHMS
OP'
3.'UH
,.
'EPS.31038.0
-"\
"1
-.-7/
Figure 5. Antenna Simulator Circuitfor Models
T1959A and T1961A (10.8-18 MHz)
1
32.'
2 OHMS
0.5U'
100
OHMS
~
AE.5-3103&-.
Figure 6. Mobile Whip Antenna Simulator Circuit
, 3.4
Select and construct the antenna simulator circuit
that corresponds to the antenna tuner model being
checked and the operating range of the radio.
CAUTION
These antenna simulator circuits are only
recommended for system tests in the tune-
up mode. Tests in other modes should on-
ly be made if the simulator circuits are
constructed with parts that are rated to
handle maximum transmitter power.
'\
-_J 3.5 To insure proper operation of the tuner, the radio
must be adjusted for a power level (in the tune
A
mode) of 3 :t 1 watts into a 50-ohm load. Refer to the
radio instruction
manual for the procedure for ad-
justing the radio power level in the tune mode.
3.6
Check the tuner operation by following the pro-
cedure given below.
Step 1. Set up the components of the radio installation
as shown in Figure 2.
Siep 2.
Select Channell and turn the radio on. During
the initial 1 to 2 seconds, the wattmeter should indicate
a power level of approximately
3 watts. The radio
should then return to the receive mode.
CAUTION
Step 3 should only be performed with an
antenna simulator rated for full transmit
power or with a properly installed anten-
na.
"':r
Step 3.
Whistle into the microphone. Check the watt-
meter for forward and reverse power levels. The for-
ward power level should be more than three times the
reverse power level.
.
Step 4.
Repeat Steps 2 and 3 for each of the other
radio. channels.
Insure
that
the .proper
antenna
simulator is used for each channel frequency.
.
4.
MAINTENANCE
4.1
RECOMMENDED TEST EQUIPMENT
The test equipment listed in Table I is recommend-
ed for maintaining and troubleshooting the automatic
antenna tuner.
Table 1. Recommended Test Equipment
4.2
PREVENTIVE MAINTENANCE
4.2.1
Check all external surfaces of the equipment to
see that they are clean. Inspect all connecting
cables and wires for damage or loose connections. It is
especially important that the ground and antenna wires
make good connections at the tuner. Carefully check the
antenna and verify that it is properly insulated from any
metal objects.
.
3
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