CPLR TUNE KW Functional Operation

TM 11-5820-873-34

coupled through the selected low pass filter (para 2-10)

signal from the selected filter when mode switch

to ANT jack 1A8J1.

1A1S13 is set to LSB, USB or CW The output from the

(18) Current ALC detector 1A7A17 monitors the

amplifier is coupled to 2nd balanced mixer 1A3A1CR9

supply current to the RF power amplifier. When the

thru 1A3A1CR12.

supply current exceeds 10 amperes, 1A7A1Q7 is turned

(12) When mode switch 1A1S13 is set to AM,

on causing current ALC amplifier 1A3A1Q4 to reduce

amplifier 1A3A2Q1, 1A3A2Q2 combines the upper

the gain of amplifier 1A3A1Q1l, 1A3A1Q3.

sideband signal with the 10.5 MHz carrier signal and

(19) ALC amplifier 1A3A3Q9, 1A3A3Q10 limits the

amplifies the combined signal ((11) above).

gain of amplifier 1A3A2Q1, 1A3A2Q2 when the VSWR

(a) The AM/CPLR TUNE KW transmit enable

is too high or the RF output voltage is too high.

signal is coupled from mode switch 1A1S13 through

(a) VSWR ALC detector 1A7A1CR4 causes the

relay 1A8K1 to turn on AM transmit switch 1A3A3Q13.

ALC amplifier to limit the gain of amplifier 1A3A2Q1,

The AM transmit switch enables automatic carrier

1A3A2Q2 when the peak voltage on the collector of

control (ACC) amplifier 1A3A3Q2, 1A3A3Q3, 1A3A3Q5.

1A7A1Q6 is too high.

(b) The gain of the automatic carrier control

(b) Reflected power detector 1A5A4CR16

amplifier is controlled by the detected carrier signal from

causes the ALC amplifier to limit the gain of amplifier

ACC detector 1A5A4CR6, 1A5A4CR12 ((20) below).

1A3A2Q1, 1A3A2Q2 when the VSWR on the RF output

The automatic carrier control amplifier amplifies the

line is too high.

10.5 MHz 3rd local oscillator signal. The amplified 3rd

local oscillator signal is injected into amplifier 1A3A2Q1,

causes the ALC amplifier to limit the gain of amplifier

1A3A2Q2 where it is combined with the upper sideband

1A3A2Q1, 1A3A2Q2 when the RF output voltage is too

signal.

high.

(13) The nominal 80.75 MHz 2nd local oscillator

(20) ACC detector 1A5A4CR6, 1A5A4CR12

signal from synthesizer 1A4 is coupled to the 2nd

reduces the gain of automatic carrier control amplifier

balanced mixer through 2nd local oscillator amplifier

1A3A3Q2, 1A3A3Q3, 1A3A3Q5. At initial turn on in AM

1A3A1Q8. The output from the 2nd balanced mixer is

transmit mode, automatic carrier control amplifier

coupled to amplifier 1A3A1Q7.

1A3A3Q2, 1A3A3Q3, 1A3A3Q5 is operating at

(14) Amplifier 1A3A1Q7 is enabled by the transmit

maximum gain ACC detector 1A5A4CR6, 1A5A4CR12

enable signal and amplifies the output from the 2nd

detects the level of carrier signal on the RF output line

balanced mixer. The 91.25 MHz (sum frequency)

and reduces the gain of the automatic carrier control

output signal from lA3A1Q7 is coupled through VHF

amplifier to establish the desired carrier signal level.

filter 1A3A1FL1 to 1st balanced mixer 1A3A1CR4 thru

(21) Power output detector 1A5A4CR5 samples

1A3A1CR7.

the voltage on the RF output line. The output from

(15) The 91.25 MHz to 121.2499 MHz 1st local

1A5A4CR5 drives meter 1A2M1 when FWD power is

oscillator signal from synthesizer 1A4 is coupled to the

selected by 1A2S1.

1st balanced mixer through 1st local oscillator amplifier

1A3A1Q5. The nominal frequency of the 1st local

oscillator signal is 91.25 MHz plus the setting of the

2-6.

CPLR TUNE KW Functional Operation

selected FREQUENCY switches.

If the selected

(Fig. FO-2)

FREQUENCY switches are set to 12.3456, the 1st local

oscillator frequency is 103.5956 MHz. The output of the

With mode switch 1A1S13 in CPLR TUNE KW, pressing

1st balanced mixer is coupled to amplifier 1A3A1Q1,

TUNE START switch 1A2S2 places the RT-1277/URC-

1A3A1Q3.

92 in the transmit mode. Relays 1A5A4K2 and 1A8K1

(16) The gain of amplifier 1A3A1Q1, 1A3A1Q3 is

are energized through the SU-2229/URC-92.

controlled by the output of current ALC amplifier

a. Overall Functional Operation. The 10.5 MHz, 3rd

1A3A1Q4 ((18) below). The current ALC amplifier limits

local oscillator signal from synthesizer 1A4 is amplified

the gain of 1A3A1Q1, 1A3A1Q3 during high current

and mixed with the 80.75 MHz, 2nd local oscillator

peaks. Amplifier 1A3A1Q1, 1A3A1Q3 is enabled by the

signal from synthesizer 1A4. The resultant signals are

transmit enable signal and amplifies the difference

amplified and passed through a 91.25 MHz (sum

frequency (equal to the setting of the selected

frequency) filter. The 91.25 MHz signal is mixed with

FREQUENCY switches) output of the 1st balanced

the 91.25 to 121.2499 MHz, 1st local oscillator signal

mixer.

from synthesizer 1A4. The difference frequency (1st

(17) RF power amplifier 1A7A1Q11 thru 1A7A1Q6

local oscillator frequency minus 91.25 MHz) is amplified

is enabled by the transmit enable signal and amplifies

to the 30-40 watt level and passed through a low pass

the HF signal from 1A3A1Q1, 1A3A1Q3 to the 100 watt

filter to ANT jack 1A8J1.

level. The output from the RF power amplifier is

b. Detailed Functional Operation.

2-6