Yaesu FC-902 - FC-902 Antenna Coupler Overview

THE FC-902 ANTENNA COUPLER
The FC-902 antenna coupler is designed for low and medium power
applications in the HY amateur bands from 160 through 10 meters.
It is designed to minimize the adverse effects of high SWR on a coaxial
line or wire antenna which may result in difficulty in tuning a transmitter
designed to work into a resistive 50 ohm load.
The FC-902 comes equipped with three UHF-type female coax receptacles,
and a threaded terminal to accept a single-wire antenna.
The front panel controls include a bandswitch for selecting proper
impedance values for matching, TUNE and LOAD controls for adjustment
of the capacitive coupling, and a POWER & SWR switch for setting
the meter sensitivity for the power being used. The ANT SELECT
switch chooses among any of four antennas to be matched, and if it
is desired to feed an antenna directly through the coupler to the trans-
mitter without any matching done by the coupler, a position of the
BAND switch will accomplish this.
High-quality low-loss components are used throughout the FC-902
antenna coupler, and-the matching function it performs means your
transmitter will always ''see"' the resistive termination it was designed
for. The inherent selectivity of the FC-902 matching circuitry helps
attenuate harmonics, too, thus reducing harmonic-related TVI or
out-of-band emission,