HARMONIC FILTER A1A2 ALIGNMENT

TM 11-5820-919-40-2

The alignment procedure is to be used in either of these d situations: (1) the

performance test calls a potentiometer out of adjustments or (2) the following is

replaced: RF Detector T1, CRT, CR2, C1, C2, C3, and C4. The procedure consists of

a preliminary setup and an adjustment procedure.

Preliminary Setup

ADJUSTMENT

1. Remove the harmonic filter from the

1. Monitor VFWD, TP1, of the module

receiver/exciter.

using the test DVM and a sharp probe.

2. Remove the cover from the power

2. Close the PTT switch on the handset

amplifier m odule of the test bed radio

and adjust the rf signal generator output

set. Disconnect the rf radio coax A1J1 at

to +19 dbm, turn the modulation level

the module and plug in the fabricated rf

control to obtain 20 watts output (2

coax cable in its place.

milliwatts indicated on the wattmeter

from the harmonic filter module.

3. Connect the test radio, module,

cables and test equipment as shown in

3. Adjust R1 to obtain +14.5 0.1 vdc

figure 4-5. Comply with notes 1-5 on.

at TP1 of the module with 20 watts module

figure 4-5.

output

4. Select the rf signal generator fre-

4. Change the DVM monitor point from

quency of 29.9999 MHz and an initial level

TP1 to A1A2P1 pin 14, VREFL (reflected

output of 0 dbm at radio. Set dc power

voltage).

supply (7 amp) to +26.5v.

5. Adjust R2 to obtain the minimum

5. See the test ratio controls on the

voltage at pin 14. It should be between

control panel and amplifier/coupler as

zero and -3.0 vdc

follows:

6. Open the handset PTT switch.

FREQUENCY KHZ to 29,999.9

Mode to V-TR

7. Disconnect the +26.5 vdc input to

ANT SEL to 50 OEM (bypass)

the radio and remove the cables connected

VOLUME to ON

to the module.