Yaesu FT-901DM Maintenance Service Manual page 169

RF UNIT (PB-2154)
The incoming signal is amplified by the RF ampli-
fier Qio1 (3SK51-03), a dual gate MOSFET which
has superior rejection against cross modulation.
The amplified signal is then fed to the first mixer
Qio2 (ND487C2-3R), a Schottky-barrier double-
balanced mixer, for excellent intercept character-
istics. The RF signal is mixed with a local signal
delivered from the LOCAL UNIT, resulting in a
8.9875 MHz first IF. The IF signal is then ampli-
fied by Qio3 (J310) and delivered to the FILTER
UNIT.
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