Yaesu FT-901DM Maintenance Service Manual page 6

GENERAL
ALL MODE HF TRANSCEIVER
FT-901DM
GENERAL DESCRIPTION
The FT-901DM is a precision engineered, high-
performance HF transceiver of advanced design,
providing all band coverage (160 - 10 meters) on
all modes of operation: LSB, USB, CW, FSK, AM,
and FM. This transceiver operates at an input
power of 180 watts SSB/CW and 80 watts on AM,
FM, and FSK.
Advanced features include PLL (Phase Locked
Loop) frequency derivation, digital plus analog
frequency readout with large display LED digits,
a built-in Curtis 8043 IC electronic keyer, and
memory frequency control circuitry. State-of-the-
art receiver performance features include rejection
tuning, dual-filter variable IF bandwidth tuning.
and, for CW, an audio peak filter (APF) for un-
surpassed rejection of unwanted signals. Other
built-in features include VOX, semi-break-in
CW with sidetone, 25 kHz calibrator, advanced
noise blanker, RF speech processor, and a 20 dB
RF attenuator for protection against receiver
overload.
All circuits, except the transmitter driver and
final amplifier stages, are solid state, utilizing
modern plug-in printed circuit boards, thus per-
mitting easy maintenance.
The FT-901DM
tained, requiring only an antenna and power source
for operation. For base station operation, AC
es of 100/110/117/200/220/234 VAC
may be chosen, though the unit normally is sup-
plied with 117 volt capability. A DC-DC converter
unit provides for mobile or portable operation.
Selection of AC or DC power source is automati-
cally made when the proper line cord is inserted.
transceiver is entirely self-con-
power vo
For mobile operation a separate switch is provided
on the front panel to turn off the tube heaters
the receive mode. With the heaters off, while in
current consumption is only 1.1 amp.
Among the available options on economy models
FT901D/SD/DE are the memory unit, the keyer
unit, the DC-DC converter, the FM unit, and the
cooling fan. Optional equipment on all models are
the 600 Hz CW filter and the 6 kHz AM filter.
The entire FT-901DM transceiver weighs approxi-
mately 18 kg., and is 342 mm wide, 154 mm high,
and 324 mm deep. A diecast front panel and
heavy-duty case provide maximum protection
against damage from shock and vibration during
travel use.