Yaesu FT-900 Operating Manual page 13

Station Installation
at the operating frequency may present too high an
SWR for proper matching with the antenna tuner, in
which case the antenna should be readjusted, or a
wide-range manual antenna tuner should be used. If
the tuner Is unable to bring the SWR down to an
acceptable level, attempting to transmit will result in an
automatic reduction in power output and increased
losses in the feedline. Operation under such condi-
tions can waste power and cause TVI, RFI and RF
feedback: it is better to install another antenna de·
signed for that band. Also, if your antenna has a
balanced leedpoint and you use a balanced feedline,
install a balun transformer between the feedline and
the transceiver's antenna jack.
Mobile Power Connection
A fused (20-A) DC power cable for mobile installa·
tion is supplied with the transceiver. Please note the
Caution at the beginning of this chapter before con-
necting power. Plan to connect the DC cable directly
to the vehicle battery, rather than to the ignition or
accessory circuitry. Route the cable as far away from
ignition cables as possible, and then cut off any extra
cable (from the battery end) to minimize voltage drop
losses. If the cable is not long enough, use 1112 AWG
stranded, insulated wire to extend it, but no more than
is necessary. Use the following procedure to connect
the cable:
0
Before connecting the cable, measure the voHage
across the battery terminals with the engine run-
ning fast enough to
show a charge. 1f above
15
vohs, the automobile voltage regulator must be
adjusted to redLtce the charging voltage before
proceeding.
0
With the radio end of the cable unconnected, con-
nect the RED cable lead to the POSITIVE battery
terminal, and the BLACK lead to the NEGATIVE
terminaL Make sure the battery terminal connec-
tions are tight, and remember to check them peri-
odically for signs of loosening or corrosion.
0
Make sure the POWER switch on the transceiver
is off, and plug the DC cable into the 6-pin molex
jack on the rear panel.
Caution!
In mobile installations, check to ensure that the
transceiver POWER switch is off whenever start-
ing or stopping the engine, to avoid damage from
switching transients.
Mobile Mounting
The optional MMB·20 Mobile Mounting Bracket
allows quick insertion and removal of the transceiver
from the vehicle. Complete instructions are provided
with the bracket, which can be mounted above or
below the transceiver.
Remote Mounting
The front sub-panel can be separated and the main
unit and mounted remotely with the optional YSK -900
Separation Kit. Operation and mounting instructions
are provided with the YSK-900.
Mobile Antenna Installation
Please review the Antenna Considerations on the
previous page, as they apply equally to base and
mobile antennas. Use the internal ATU-2 antenna
tuner whenever possible in mobile installations, where
the short antenna elements have very narrow band·
width. Make sure that the shield of the antenna coax
is firmly grounded to the car body at the antenna
feedpoint if using a base-loaded vertical.
Interconnection of Accessories
The diagrams on the next page show interconnec-
tions of external accessories.
If
you have any ques-
tions on these accessories or connecting devices not
shown, contact your dealer for advice.
Memory Backup
The BACKUP switch inside the hole at the front
center of the bottom panel is turned on at the factory,
allowing VFO and memory data to be retained while
power is off. Backup current is miniscule, so it is not
necessary to tum the BACKUP switch off except for
long-term storage of the transceiver.
After about five years the transceiver may fail to
retain memories (although operation will be otherwise
unaffected), and the lithium battery should be re-
placed. Ask your dealer for replacement of the battery,
or for instructions on how to do so yourself.
OFF
S2001
t
ON
D
ON~
OFF
OFF+-+- O N
Switch Locations in Bottom Cover
page9