The solid-state radar transponders are installed at known locations and serve us reference points in the Mini-Ranger System. The two transponders receive pulse-coded interrogations from the on-board transmitter. The interrogations are decoded (if the pulse spacings are correct) by each transponder, resulting in a transponder reply. The transponder interrogation and reply frequencies are outside the normal passband of radar receivers.

Radar Transponder

Input voltage                               24to 30 volts dc

Power consumption                      13 watts, nominal

(1) Receiver, frequency                 5570MHz (tunable)

(2) Receiver, bandwidth                18MHz, nominal

(3) Receiver, sensitivity                 -70dBm

(4) Receiver, signal input (max.)   +20 dBm

(5) Transmitter, frequency             5480MHz (tunable)

(6) Transmitter, power output        400 watts (peak)

(7) Transmitter, reply pulse            Single or coded

(8) Transmitter, reply pulse            0.5 µsec width

(9) Operating temperature             -54C to +71 C (-65 F to +1.60 F)

Transponder Antenna (13 dB gain)

(1) Frequency range                       5400 to 5600 MHz

(2) Polarization                               Horizontal

(3) Gain                                         13 dB, nominal

(4) Beam width (3 dB)

Azimuth                               80° (E-plane)

Elevation                             15° (H-plane)

(5) Environmental                           Same as transponder