page 10
MARK-V FT-1000MP Operating Manual
A
NTENNA
C
ONSIDERATIONS
Loss figures are approximate; consult cable manufac-
turers’ catalogs for complete specifications.
Loss figures can increase significantly if high SWR is
present on the transmission line.
A
DJUSTING
THE
F
RONT
F
EET
The two front feet of the MARK-V FT-1000MP can
be set in either of two positions. By turning the knurled
ring around a (retracted) foot clockwise, the middle of
the foot will extend about one centimeter. Turn the ring
as far as it will go (about ¼-turn) to lock the extended
foot in place. To retract an extended foot, turn the
knurled ring counterclockwise ¼-turn while pressing
on the center of the foot.
G
ENERAL
S
ETUP
M
EMORY
B
ACKUP
The memory BACKUP switch on the rear 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 turn the BACKUP
switch off unless the transceiver is to be stored for an
extended period.
After five or more years of operation the transceiver
may fail to retain memories, at which time the lithium
battery should be replaced. Contact your dealer for
replacement of the battery; for instructions on how to
do so yourself, see page 114.
Loss in dB per 30m (100 feet)
for Selected 50
Coaxial Cables
(Assumes 50
Input/Output Terminations)
(To Retract)
(To Extend)
The MARK-V FT-1000MP is designed for use with
any antenna system providing a 50
resistive imped-
ance at the desired operating frequency. While minor
excursions from the 50
specification are of no con-
sequence, the transceiver’s Automatic Antenna Tuner
may not be able to reduce the impedance mismatch to
an acceptable value if the Standing Wave Ratio (SWR)
present at the Antenna jack is greater than 3:1. Among
the undesirable consequences that high SWR may
produce are:
r
The transceiver’s power amplifier protection circuitry
will reduce power if the Automatic Antenna Tuner is
unsuccessful in reducing the SWR.
r
Even if the Automatic Antenna Tuner successfully
normalizes the impedance presented to the radio,
feedline losses will escalate rapidly with increasing
SWR at the higher operating frequencies, especially
28 MHz.
r
Although high SWR itself does not cause feedline
radiation, the sudden onset of high SWR may well
indicate a mechanical failure in a matching device,
leading to an electrical condition which
may
cause
excessive feedline radiation, which can cause in-
terference to nearby home-entertainment devices.
Every effort should, therefore, be made to ensure
that the impedance of the antenna system utilized with
the MARK-V FT-1000MP be as close as possible to
the specified 50
value.
Any antenna to be used with the MARK-V FT-
1000MP must, ultimately, be fed with 50
coaxial
cable. Therefore, when using a “balanced” antenna
such as a dipole, remember that a balun or other match-
ing/balancing device must be used so as to ensure
proper antenna performance.
The same precautions apply to any additional (re-
ceive-only) antennas connected to the RX ANT jack; if
your receive-only antennas do not have an impedance
near 50
at the operating frequency, you may need to
install an external antenna tuner to obtain optimum
performance.
Use high-quality 50
coaxial cable for the lead-in
to your MARK-V FT-1000MP transceiver. All efforts at
providing an efficient antenna system will be wasted if
poor quality, lossy coaxial cable is used. Losses in co-
axial lines increase as the frequency increases, so a
coaxial line with only 0.5 dB of loss at 7 MHz may have
2 dB of loss at 28 MHz. For reference, the chart in the
next column shows approximate loss figures for typi-
cally-available coaxial cables frequently used in ama-
teur radio installations.
Cable Type
RG-58A
RG-58 Foam
RG-8X
RG-8A, RG-213
RG-8 Foam
Belden® 9913
RG-17A
Loss:
2 MHz
0.55
0.54
0.39
0.27
0.22
0.18
0.88
Loss:
15 MHz
1.75
1.50
1.07
0.85
0.65
0.50
0.30
Loss:
28 MHz
2.60
2.00
1.85
1.25
0.88
0.69
0.46
