Caution - Telephonics RDR-1600 Pilot's Manual

Appendix (Cont.)
EXAMPLE
The following is typical data for the airborne weather radar.
Antenna Diameter: 18 inches = 45.6 cm
Transmitter Frequency: 9375 +30 MHz
Wave Length: 3.2 cm
Pulse Length: 2.5 microseconds (search)
Pulse Repetition: 200 Hz
Peak Power: 10 kilowatts
Average Power: 5 watts (search)
Antenna Gain: 1250 (31 dB)
Calculations
(1) Distance (Ri) to the near field/far field intersection
Ri = Gλ
8π
Ri = (1250 x 0.032)
8π
=1.6 meters = 5.25 feet
2
(2) Distance (Rs) to 1 mw/cm safe limit
GP
Rs =
π
40
(1250)(5)
=
π
40
= 7.05 meters = 23.1 feet
The distance (Rs) is greater than (Ri), therefore, the minimum safe distance
is 23.1 feet.
A-2 RDR-1600 Pilot's Guide
Maintain prescribed safe distance when standing in front of radiating
antenna.
Never expose eyes or any part of the body to an unterminated wave
guide.
TM106101(8/01) TM106101(8/01)

CAUTION

RDR-1600 Pilot's Guide
Appendix (Cont.)
A-3