Yaesu FT-857 HF, Техническое дополнение

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16
Alignment
RX Adjustment
SSB IF Adjustment
1. Connect the signal generator to the HF/50 MHz an-
tenna jack, and the AF milivoltmeter and the SINAD
meter to the speaker jack.
2. Tune the transceiver to 51.995 MHz, and switch off
the ATT and IPO feature. Inject a 51.995 MHz signal
from a signal generator at 0 dBµ output.
3. Adjust
T1018
,
T1019
,
T1024
,
T1026
,
T1028
,
T1030 , T1035 , T1036 , T1037 , T1034 and T1029
on the MAIN UNIT alternately for maximum indica-
tion on the AF milivoltmeter. Several passes may be
necessary, as the adjustments inter-react to some de-
gree.
FM IF Adjustment
1. Connect the signal generator to the HF/50 MHz an-
tenna jack.
2. Tune the transceiver to 51.995 MHz. Inject a 51.995
MHz signal from a signal generator at 5 dBµ output,
with 1 kHz AF FM modulation at ±3.5 kHz deviation.
3. Adjust T1024 , T1026 , and T1028 on the MAIN Unit
alternately for maximum level on the S-meter.
Air-Band Reception Adjustment
1. Connect the signal generator to the HF/50 MHz an-
tenna jack, and the DC voltmeter to
TP1044
on the
MAIN Unit.
2. Tune the transceiver to 128.000 MHz in the AM mode.
Inject a 128.000 MHz signal from the signal generator
at 20 dBµ output, with 30% AM modulation at 400 Hz
audio frequency.
3. Adjust
T1005
and
T1008
for minimum indication on
the DC voltmeter.
VHF Band Alignment
1. Connect the signal generator to the 144/430 MHz an-
tenna jack, and the DC voltmeter to TP1044 on the
MAIN Unit.
2. Tune the transceiver to 145.995 MHz in the CW mode.
Inject a 145.995 MHz signal from a signal generator
at 20 dBµ output.
3. Adjust
T1006
,
T1009
, and
T1010
alternately for mini-
mum indication on the DC voltmeter.
UHF Band Alignment
1. Connect the signal generator to the 144/430 MHz an-
tenna jack, and the DC voltmeter to
TP1044
on the
MAIN Unit.
2. Tune the transceiver to 439.995 MHz in the CW mode.
Inject a 439.995 MHz signal from the signal generator
at 20 dBµ output.
3. Adjust TC1001 for minimum indication on the DC
voltmeter.
W-FM Reception Adjustment
1. Connect the signal generator to the 144/430 MHz an-
tenna jack, and the SINAD meter to the speaker jack.
2. Tune the transceiver to 88.000 MHz. Inject an 88.000
MHz signal from the signal generator at 30dBu out-
put, with ±22.5 kHz deviation FM modulation of a 1
kHz audio signal.
3. Adjust TC1005 for the best SINAD sensitivity. Then
reduce the output level of the signal generator to where
the signal just begins to sound slightly “noisy,” and
adjust
TC1005
again for best SINAD.
Image Rejection Trap Adjustment
1. Connect the signal generator to the HF/50 MHz an-
tenna jack, the AF millivoltmeter to the speaker jack.
2. Tune the transceiver to 51.995 MHz in the FM mode.
Inject a 68.330 MHz signal from a signal generator at
70 dBµ output, with 1 kHz AF FM modulation at ±3.5
kHz deviation
3. Adjust T1004 for minimum indication on the AF
millivoltmeter. Then increase the output level of the
signal generator slightly and adjust
T1004 again, so
as to ensure maximum notching of the image.
Noise Blanker Adjustment
1. Connect the signal generator to the HF/50 MHz an-
tenna jack, and the DC voltmeter to
TP1043
on the
MAIN Unit.
2. Tune the transceiver to 51.995 MHz and inject a 51.995
MHz signal from the signal generator at 20 dBµ out-
put.
3. Activate the noise blanker, and adjust T1027 and
T1031
for minimum indication on the DC voltmeter.