TB 9-6625-2237-24
9. Power Measurement
a. Performance Check
(1) Remove TI CALIBRATION ADJUSTMENT RF MODULE cover plate.
(2) Install calibration antenna as listed in (a) through (e) below:
(a) Unlatch and open TI test chamber cover.
(b) Install the calibration antenna No. 1 (243.0 MHz) on the antenna plate assembly.
(c) Move the load carriage fully toward antenna base.
(d) Attach antenna plate assembly to the key slots on the end of the test
chamber and place antenna between load carriage contacts.
(e) Close and latch test chamber cover.
(3) Set RADIO SELECT switch to PRC-90 (243.0) position.
NOTE
The test chamber interlock switch will not disable RF
transmission during this calibration process if the test chamber
is unlatched or open. Do not unlatch or open test chamber
during calibration process unless the signal generator RF
OFF/ON switch has been pressed to OFF position.
NOTE
To prepare TI for minimum power reflected
power
measurement, perform either (a) or (b) below:
(a) Insert flexible nylon ledger post through antenna base plate into
small hole of load carriage.
(b) Slightly twist nylon ledger post.
(c) Load carriage can now be moved back and forth for null indication with RF
power on.
(d) Drill 1/4" hole to right of BNC connector.
(e) Insert flexible nylon ledger post through hole.
(f) Same as (3) (a) above.
Set REC TEST/XMIT TEST switch to XMIT TEST position.
(4)
NOTE
Observe polarity connections for (5) below and monitor dc
power supply with multimeter (dc mode).
Connect dc power supply to RF module EXT PWR TEST SET test points.
(5)
Adjust dc power supply controls for a multimeter indication between 12.5 and 13.5 V dc.
(6)
Connect equipment as shown in figure 2.
