Transmitter power output

suits shall be considered acceptable when

receiver-transmitter. Serious damage to

the performance is within the limits spe-

the pad and signal generator may result.

c i f i e d without further adjustment of

2. Do not perform any tests until the

the respective controls.

receiver-transrnitter has been allowed to

warm up for at least one minute.

(c) Channel changing tone. A tone of ap-

3. Transmission should not be at-

proximately 800 Hz shall be present at the re-

tempted during the channel changing

ceiver audio output during the complete channel

cycle.

changing cycle. The tone shall be of sufficient

( a ) Transmitter power output. U n d e r

magnitude to be clearly audible after installation

standard conditions of (1) above and with the

of the AN/ARC54 subsystem in the designated

test set up as shown in figure 1, check the trans-

aircraft.

mitter for a minimum of 10 watts output at the

(d) "X" mode deviation test. Under stand-

following frequencies in sequences specified. The

ard conditions of (1) above and with the test set

maximum error for each frequency shall not be

up as in figure 2, perform the following tests:

greater than 0.01 percent. Allocated frequencies

1. Adjust the audio oscillator for zero

shall be made part of this unit.

signal output, Set the transmitter frequency to

Frequency (MHz)

Frequencey (MHz)

30 MHz. Key the transmitter and measure the

7. 50.55

1. 30.00

deviation. The deviation shall be 3 kHz 0.5 kHz.

8. 55.65

2. 34.10

9. 59.75

3. 37.20

2. Connect pin no. 39 of P1005 to ground

10. 63.85

4. 38.00

(pin no. 38) ; the deviation shall be zero.

11. 67.95

5. 40.30

3. With pin no. 39 connected to ground,

12. 69.95

6. 44.45

adjust the audio oscillator for a signal input level

NOTE

of 8.2 0.5 Vrms at 1000 Hz between pins no. 7

The RF cabling arrangement shown in

and no. 38 (ground) of P1005. The deviation

figure 1 shall be replaced with a single

shall be 9.5 2.5 kHz.

RG58/U or RG223/U cable between

(5) Receiver tests.

the receiver-transmitter unit and the

(a) Audio output test: Under standard

AN/URM120 for this test. The input

conditions of (1) above and with the test set up

voltage shall be at least 27.5 vdc at the

as shown if figure 3, perform the following test.

transmitter fuse for this test.

Using a 30 MHz signal modulated 10 kHz set

(b) Frequency deviation and sidetone test.

the signal generator AN/URM48 output level to

Under standard conditions of (1) above and with

provide 100 microvolt input to the receiver-trans-

the test setup as shown in figure 1, set the trans-

mitter antenna, (terminal P-1002). The audio

mitter to operate at 30.00 MHz. Adjust the audio

output shall be not less than 41.6 milliwatts (2.50

oscillator TS-382A/U for a signal level of 0.37

Vrms across the volume control when adjusted

V r m s at 1000 Hz between pins Y and KK

f o r maximum volume.) If necessary, adjust

(ground) of J-101. The frequency deviation shall

"GAIN" control R1315 of the receiver audio

be 10 kHz. (If the deviation is not within these

module to obtain the specified output.

limits, adjust "AUDIO" control R-1402 on the

transmit audio module, for a deviation of 10

(b) Sensitivity tests. Under standard con-

kHz. ) The sidetone output level shall be 1.09 Vrms

ditions of (1) above and with the test set up as

as measured with the VTVM across the volume

shown in figure 3, set the C-3835( )/ARC54

control when adjusted for a maximum volume.

c o n t r o l s for receive operation OFF-PTT-RE-

(Adjust "SIDETONE" control R1413, as neces-

TRAN-HOME switch to PTT and the SQUELCH

sary to achieve the specified output. ) Remove the

switch to DIS and the volume control fully clock-

audio input and key the transmitter. The devia-

wise. Set the signal generator output level as in-

tion shall be 3000 Hz 500 Hz. Connect a 0.2 mf

dicated in figure 3, deviated 10 kHz at 1000 Hz

capacitor across the modulation meter ME57/U

and measure the signal plus noise-to-noise ratio.

AUDIO OUTPUT terminals and check the tone

The ratio shall be 10 db or greater. Conduct this

frequency as indicated on the frequency meter

test at the following frequencies:

AN/USM-26. The tone frequency shall be 150

MHz

Hz 3 Hz.

30.00

38.25

48.50

60.80

69.95

33.05

42.35

52.60

64.90

NOTE

36.15

47.40

56.70

67.05

Due to an interaction between the

"SIDETONE" control R1413 and the

(c) Squelch sensitivity. U n d e r standard

"AUDIO" control R1402, the test re-

conditions of (1) above and with the test set up