Alinco DR-570T/E, Service Manual

Page: 16 / 51

■ ADJUSTMENT (UHF)
Item
A d ju stm en t
p o int(s)
A d ju stm en t m ethod
VCO Voltage [D]TC1
TC2
(VCO BOX)
At 445.000 MHz (T) or 435.000 MHz (E), adjust TC1 so that the voltage
of TP3 on [
b
] substrate is 1.8 V.
At 445.000 MHz (T) or 435.000 MHz (E), pressing the PTT button,
adjust TC2 so that the voltage of TP3 on [%] substrate is 3.8 V.
d L 4
(VCO BOX)
At 145.000 MHz, adjust TP2 so that the voltage of TP2 on
[
a
]
substrate
is 4.0 V.
TX Power
d V R 5
On “Lo” position, pressing the PTT button, adjust VR5 so that the
power is maximum at 444.95 MHz (T) or 434.95 MHz (E).
Power Output [B] VR5 (Hi) On “Hi” position, turn VR5 for 35 W output at 444.95 MHz (T) or 36 W
output at 434.95 MHz (E).
Verify the lighting of the entire RF meter.
[
b
] VR7 (Lo) On “Lo” position, turn VR7 for 5 W output at 444.95 MHz (T) or
434.95 (E).
RF meter [
b
] VR6
On “Lo” position, adjust VR1 so that [ 5 ] on the RF meter lights up at
444.95 MHz (T) or 434.95 MHz (E).
Deviation
[
b
] VR3
Enter the AF level of QdBm, then pressing the PTT button, adjust VR3
so that you obtain 4.6 KHz/Dev at 444.95 MHz (T) or 434.95 MHz (E)
and AF 1 kHz.
SubaudibleTone
Deviation
(DR-570T) Pressing the tone button and the PTT button at 444.95 MHz, verify
0.5—1 kHz/Dev at tone frequency of 88.5 Hz.
1750 Hz Tone
Deviation
(DR-570E)
Connect Microphone (EHM-34A or 33A), then pressing the tone button,
verify that the tone frequency is 1750 Hz and the deviation is 3.5 (±0.1)
kHz.
Helical Filter 1]TC 1,2
L3, 4
Connect a tracking generator to the antenna and a spectrum analyser
to TP1, then adjust TC1, 2 and L3, 4 so that the sensitivity is at its peak
between 440 and 450 MHz at maximum gain.
(570 E: 430-440 MHz)
Discrimination
(U L9, 11
At 445.03 MHz (T) or 435.03 MHz (E) and 60 dB|i input, adjust L9, 11
so that the distortion is minimum at 50m W.
Sensitivity ¡J] L8, TC3 Adjust L8 and TC3 so that 12 dB SINAD sensitivity is the highest at
445.03 MHz (T) or 435.03 MHz (E).
Squelch ¡B] VR1 1) At 146.03 MHz (T) or 145.03 MHz (E) of the main band, cut the SG
output power and adjust the main squelch knob so that the noise is
intermittent.
2) At 445.03 MHz (T) or 435.03 MHz (E) of the main band, cut the SG
output power and adjust VR1 so that the noise is intermittent.
S-meter (B]VR2 At 445.03 MHz (T) or 435.03 MHz (E) and-3 dBn [EMF], adjust VR2 so
that Q] in the S-meter begins to light.
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