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3 THEORY OF OPERATION, ANTENNA COUPLER
3.1 FUNCTIONAL DESCRIPTION: PC-1000B
3.1.1 Impedance Transformer
The impedance transformer matches the 50 ohm output impedance of
the transmitter to any impedance from 2 to 25 ohms. The impedance
transformation is chosen by selecting one of eleven taps in the
transformer secondary.
3.1.2 Tuner
The tuner is a 240 turn coil with taps for coarse adjustment and
a rotatable shorted turn for fine adjustment. Tuning range is from
22 uH to 3.6 mH which is sufficient to tune any practical antenna
in the 190 - 625 KHz frequency range.
3.1.3 Autotune
The autotune circuit compares the phase of the voltage and current
at the input to the coupler and turns the shorted ring in the tuner
in the proper direction to tune the antenna system.
3.1.4 Antenna Current/Tuning Meter
This meter indicates antenna current in two ranges. It also detects
reflected power to indicate tuning. The meter function is determined
by a four position switch.
SS-800AVS
Southern Avionics
69
Company
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