Yaesu FT-900 Operating Manual page 12

Station Installation
AC Power Supply
The FT-900 is des1gned for operation from 13.5-V
DC. negative ground For base station installations,
we recommend the matching Yaesu FP-800 AC power
supply which was specifically designed for this pur-
pose, and which includes a large loudspeaker lor the
transceiver and its own cooling fan. You can use
another DC source capable of providing 20 amperes
at 13.5-V DC with the supplied DC cable assembly. but
you
must be extremely careful to all04d reversed polar-
Ity connection. See the Caution box below.
If you are connecting the FP-800 with the FT-900,
before connecting power. check the label on the roar
of the FP-800 which indicates the AC mains voltage
range for which the supply is currently set. If your AC
mains voltage is outside of this range, the transformer
taps inside the power supply must be rewired, and the
fuse in the FP-800 must be changed. This involves
some soldering of the AC ma1ns 1nput (see previous
page, bottom). so you should ask your dealer for
assistance it you are not experienced with this sort
of
work. Incorrect connections could cause serious dam-
age
not covered by the warranty.
In any case, make sure the power supply is set
correctly before connecting power. If you have any
doubts about the procedure. ask your dealer for help.
Also make sure the fuse in the FP-800 rear panel
fuse holder 1s correct lor your mains voltage:
AC Mains Voltage
100-117
200-234
Fuse Capacity
8A
4A
After making certain the AC voltage for which the
power supply is set matchos your mains voltage, and
that the correct fuse is installed in the fuse holder.
connect the DC cable from the power supply to the
jack on the rear panel. Don't plug the power supply
cord into the wall until all other transceiver intercon-
nections have been made.
Caution!
Permanent damage can result if tmproper supply
voltage is applied to tho transceiver. Your warranty
does not cover damage caused by application of
AC, reversed polarity DC. or OC outside of the
specified range ol13.5 V .1:10%.
If you wish to use a power supply other than the
FP-800. you must make certain that the DC supply
connector to the transoe1ver matches the FT-900
requirements. See the DC connector pinout on the
rear panel fold-out. Other manulacturers have
power supplies with a physically matched connec-
tor that is wired differently: this will cause serious
damage to the FT-900.
pageB
Transceiver Location
To assure long hfe of the components, make sure
to provide adequate ventilation around the cabinet.
The cooling system
of
the FT-900 must be free to draw
cool air in at the bottom rear of the transceiver. and to
expel warm air out of the upper rear panel. Do not
place the transceiver on top of another heat-generat-
ing device such as a linear amplifier, and do not place
equipment. books or papers on top
of
the transceiver.
Place the transceiVer on a hard, flat surface. AII04d
heating vents and w1ndow locations that could expose
the transceiVer to excessive direct sunlight, especially
•n hot climates.
In addition to the above, 11 you choose to separate
the front sub-panel and mount the transceiver body In
a remote location, choose both mounting locations
carefully. If mounting the main body in the trunk of
a
vehicle, ensure a stable flat surface capable
of
sup-
porting the weight of the transceiver is available tor the
mounhng bracket.
Do
not mount the transceiver 1nto
hberboard, plastic or other materials sometime used 1n
automotive constructiOn. Find a location that permits
mounting the bracket bolts through rigid sheet metal,
such as the transmission hump or trunk structural
support members. The front sub-panel is lightweight.
and can be mounted almost anywhere on the dash-
board, but as stated before, avoid areas where it might
be exposed to direct heat and sunlight.
Grounding
For protection
I
rom shock and proper performance,
connect the GND term1nal on the rear panel to a good
earth ground, using a heavy braided cable of the
shortest length possible. Warning!! Do not use gas
line for station grounding!. All other station equipment
should be connected to the same grounding cable, as
close together as practical.
If
you use a computer with
or near the FT-900, you may need to experiment with
grounding of both the transce1ver and the computer to
suppress computer n01se 1n the receiver.
Adjusting the Front Panel Angle
II your installation places the FT-900 much below
eye level, you may want to prop up the front. A wire bail
on the bottom of the FT-900 can be folded down for
this purpose.
Antenna Considerations
Any antenna connected to the FT-900 should have
a coax.ial feedline with
so-n
1mpedance, and include a
well-grounded lightmng arrestor. The internal ATU-2
and external FC-.800 antenna tuners are capable of
matching antennas with an SWR of up to 3:1 or more
on the amateur bands to the transmitter. Nevertheless.
optimum performance for both reception and trans-
mission will generally result with an antenna designed
to provide a
50-Q
unbalanced resistive load at the
operating frequency. An antenna that is not resonant