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1. Noise detector
2. Field strength detector
The S meter voltage from IC5 (LA1231N)
in DT2
is
detected and, when the field strength exceeds 70 dB
with respect to the ANT input voltage, the IC7 output
goes "H" = 14V. This is 5V/OV converter and supplied
to the microprocessor.
KT-990D
oT2
AF OUT
+3115V)
To Microprocessor
Sv: NARROW
Ov: WIDE
+BU15V)
S-METER
(X13)
Sv: DIRECT
OV: DISTANCE
—B (~13V)
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