Antenna Tuner (Fc-20) Operation - Yaesu FT-847 Operating Manual

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OPERATION
The optional FC-20 (external) Automatic Antenna Tuner may be helpful, in some installations, in maintaining a
satisfactory impedance match between your coaxial feedline and the FT-847's final amplifier stage. The FC-20
operates on the 160 through 6 meter bands, and is capable of achieving an impedance match in the presence of up
to 3:1 SWR (impedance range: 16.5 ~ 150 ) on HF, and 2:1 SWR on 50 MHz (25 ~ 100 ). On the 144 and
430 MHz bands, high SWR causes losses in your coaxial cable to escalate rapidly, so impedance problems should
be resolved by adjustments at the antenna feedpoint.
The FC-20 is not designed to accommodate the widely varying impedance presented by "random-length" or "long
wire" antennas.
O
P
PERATING
ROCEDURE
Connect the FC-20 between the FT-847 and your
antenna system as shown on page 10.
Determine if you need to use the FC-20 on the 50
MHz band. If so, using Menu #28, route the power
output on 50 MHz via the HF antenna jack (see
page 87.
ƒ
Set the RF PWR control fully clockwise.
Press the front panel's [TUNER] switch momen-
tarily; this will turn the FC-20 On.
...
Press the front panel's [TUNER] switch for ½ sec-
ond to initiate antenna tuning. The "WAIT " icon
will appear on the display during tuning, and will
disappear when a match has been achieved. If a
satisfactory match cannot be achieved by the tuner,
the "HI SWR" icon will appear on the display, and
you should make adjustments or repairs to your an-
tenna system to resolve the problem.
If you wish to turn off the antenna tuner's match-
ing circuitry, press the [TUNER] key momentarily.
60
A
T
NTENNA
UNER
( FC-20 ) O
PERATION
Note: The power level used during tuning depends on
the setting of the RF PWR control. We recom-
mend that this control be set for a power output
of about 50 Watts maximum for antenna tuning
purposes. Antenna tuning is accomplished us-
ing a "CW" carrier, although the mode indica-
tion will not change to "CW" (if you are oper-
ating on another mode) during antenna tuning.
FT-847 O
M
PERATING
ANUAL

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