Transponder - P-340

T-34C INSTRUMENTS

CHAPTER FOUR

408.

TRANSPONDER

Reference: T34C NATOPS, Chapter 19, Transponder (TDR950); Part VI, IFF/SIF.

Although it is considered a piece of identification equipment the transponder (Figure 48) will be

discussed here since it is used in conjunction with navigation equipment.

The transponder set is an identification, position tracking, and emergency tracking device. An

operating transponder receives, decodes and responds to interrogation by search radar.

Use of the transponder involves the setting of proper codes, setting the function selector to the

desired mode of operation and use of the reply/ident button.

SBY

ALT

OFF

TST

DIM

REPLY

IDENT

Figure 48 Collins Transponder

Each code selector switch is used to set a digit 0 through 7. The function switch can bring the unit

from an OFF to a STANDBY condition. In the ON position the unit is in operation, without the

altitude encoding function. Placing the switch in the ALT position enables this function. In the

TEST position illumination of the reply lamp indicates operational capability.

The reply/ident button will flash on and off in response to interrogation by radar. This occurs in the

ALT or ON mode. The intensity of the flashes can be controlled by rotating this button. If the

button is depressed while in the ALT or ON Mode the reply lamp will light for approximately 20

seconds. At the same time the radar operator will see a distinct reply on his scope which facilitates

identifying your aircraft.

409.

BASIC CONFIGURATIONS

Basic airspeeds and configurations used in executing the various Radio Instrument Procedures

are listed below.

CRUISE CONFIGURATIONS:

Fast Cruise

1. 170 knots

2. Approximately 750800 ftlbs

INTRODUCTION TO RADIO INSTRUMENTS 4-11