TABLE 2-2. AMPLIFIER/COUPLER CONTROLS AND INDICATORS

TM 11-5820-919-12

vswr condition but no permanent change and no retune.

the antenna in use cannot be matched by the antenna

A permanent change in antenna impedance will cause a

turner, or if the turner module is faulty. When operating

retune when the PTT switch is pressed.

in the bypass mode, the presence of sidetone provides

assurance that the rf is being generated and made

available to the antenna. If a short beep is heard at the

2-15.

BYPASS

MODE.

The antenna tuner is

beginning of each transmission, the antenna vswr is

extremely efficient but some losses are inevitable . The

worse than 4:1, but may still provide useful

bypass mode (ANT SEL switch set 50 position and

communications. If the antenna length, or height above

antenna connected to the BNC connector) can be used

ground, or coax feed line can be adjusted to reduce the

to provide 10 to 20 percent more rf power to the antenna

antenna vswr, the beep will cease, and communications

when the antenna VSWR is less than 1.5:1 (33 thru 75

will be very nearly optimum for that particular set of

ohms). The bypass mode can be very useful if

conditions.

TABLE 2-2. AMPLIFIER/COUPLER CONTROLS AND INDICATORS

NOTE

Prefix reference designators with A2

Reference

Control/Indicator

Designator

Function

Socket connector

Interface connection with receiver/exciter

Antenna socket

...

Screw-in connection for shock mount of whip antenna

ANT SEL switch

Selects whip socket either through antenna tuner, or

BNC connector through antenna tuner, or BNC con-

nector with antenna tuner bypassed (50 f impedance

antennas only)

BNC connector

Provides BNC connection to compatible antennas

other than the whip

GND terminal

Ground point for counterpoise or earth ground

2-4