Loop-Back Adjustments

TM 11-5805-424-15/NAVELEX 0967-220-9010/TO 31W2-2G-41

(3) Operate the digital data transmitting

(12) Adjust the OUTPUT LEVEL ADJ control

until the ME-30A/U indicates the desired output level;

equipment.

then, disconnect the ME-30A/U and the oscilloscope.

(4) Adjust the OUTPUT LEVEL ADJ control

(13) Connect

the

attentuator

between

(fig. 3-1) until the ME-30A/U indicates the desired output

terminals 12 and 15 of terminal board TB2 (fig. 2-2).

level (between +3 decibels (referred to 1 milliwatt in 600

ohms) (dBm) and -20 (dBm)).

(14) Connect the ME-30A/U to terminals 15

and 16 of terminal board TB2.

(5) Disconnect the ME-30A/U.

(15) Connect the oscilloscope (set to observe

d. Alarm Adjustments.

a 2-second pulse) between jack J4 on assembly A9 (fig.

(1) Connect the oscilloscope between jack J3

1-5) and ground.

of assembly A12 (fig. 1-5) and ground.

(16) Adjust the attenuator until the ME30A/U

(2) Operate the oscilloscope to observe a

indicates the desired receive carrier level.

5second pulse.

(17) Adjust the attenuator until the ME30A/U

(3) Operate the INPUT SELECT switch (fig.

indicates 20 dB less than the desired receive carrier

2-3) to OFF. Adjust the TRANSITION ALARM TIME

level.

TRANSMIT control to obtain a ground level indication

(18) Adjust the REC CARRIER ALARM

on the oscilloscope 5 seconds ±5 percent after the

THRESHOLD control (fig. 2-3) until the oscilloscope

INPUT SELECT switch is operated; then, disconnect the

indicates a continuous +6-volt level; then, slowly reverse

oscilloscope.

the adjustment direction until the oscilloscope indicates

(4) Connect the oscilloscope between jack J4

a -6 volt level.

on assembly A11 (fig. 1-5) and ground.

(19) Adjust the attenuator for the desired

(5) Operate the INPUT SELECT switch (fig.

receive carrier level; the oscilloscope will indicate -6

2-3) to OFF. Adjust the TRANSITION ALARM TIME

volts dc.

RECEIVE control to obtain a ground level indication on

(20) Adjust the attenuator until the ME30A/U

the oscilloscope 5 seconds ±5 percent after the INPUT

indicates 20 dB less than the desired receive carrier

SELECT switch is operated; then, disconnect the

level. Adjust the REC CARRIER ALARM TIME control

oscilloscope.

(fig. 2-3) to obtain a -6volt dc level on the oscilloscope 2

(6) Connect the ME-30A/U across terminals

seconds after the attenuator is operated.

12 and 13 of terminal board TB2 (fig. 2-2).

e. Oven Temperature Adjustments.

(7) Connect the oscilloscope (set to observe

a 2-second pulse) between jack J4 on assembly A6 (fig.

(1) General. Oven temperature has been

1-5) and ground.

pre-set at the factory or depot and R1 (figs. 2-6, 2-7 or

2-8) is locked and staked with varnish. Readjustment

(8) Adjust the OUTPUT LEVEL ADJ control

should normally not be required. When temperature

(fig. 3-1) until the ME-30A/U indicates 10 decibels (dB)

reading or readjustment is considered necessary it

below the desired output level (c above).

should be performed only in accordance with procedure

(9) Adjust the XMIT ALARM THRESHOLD

provided in (2) below.

control (fig. 2-3) until the oscilloscope indicates a

continuous ground level; then, slowly reverse the

CAUTION

adjustment direction until the oscilloscope indicates a

Setting of R1 should not be changed

positive level.

unless done in accordance with

(10) Adjust the OUTPUT LEVEL ADJ control

procedure.

Adjustment of R1

(fig. 3-1) for the desired output level on the ME-30A/U;

without use of proper temperature

the oscilloscope will indicate a positive level.

indicator can result in high oven

(11) Adjust the OUTPUT LEVEL ADJ control

temperature, which will seriously

(fig. 3-1) until the ME-30A/U indicates 10 dB below the

damage or destroy components

desired output level.

Adjust the XMIT CARRIER

within the oven assembly.

ALARM TIME control (fig. 2-3) to obtain a ground level

indication on the oscilloscope 2 seconds after the

OUTPUT LEVEL ADJ control is operated.

Change 6

2-8