BendixKing IN-182A System RDR-2000 - Manual (Page 11)

Effective Date: 5/98 RDR 2000 Pilot's Guide: Rev 3
7
Theory of Operation
THEORY OF OPERATION
GENERAL
The primary use of this radar is to aid the pilot in avoiding thunderstorms
and associated turbulence. Since each operator normally develops spe-
cific operational procedures for use of weather avoidance radar, the fol-
lowing information is presented for use at the operator’s discretion.
Operational techniques for the RDR 2000 are similar to earlier genera-
tion weather avoidance radars. The proficient operator manages
antenna tilt control to achieve best knowledge of storm height, size, and
relative direction of movement.
RADAR PRINCIPLES
Radar is fundamentally a distance measuring system using the principle
of radio echoing. The term RADAR is an acronym for RAdio Detecting
and Ranging. It is a method for locating targets by using radio waves.
The transmitter generates microwave energy in the form of pulses.
These pulses are then transferred to the antenna where they are focused
into a beam by the antenna. The radar beam is much like the beam of
flashlight. The energy is focused and radiated by the antenna in such a
way that it is most intense in the center of the beam with decreasing
intensity near the edge. The same antenna is used for both transmitting
and receiving. When a pulse intercepts a target, the energy is reflected
as an echo, or return signal, back to the antenna. From the antenna, the
returned signal is transferred to the receiver and processing circuits
located in the receiver transmitter unit. The echoes, or returned signals,
are displayed on an indicator.
Radio waves travel at the speed of 300 million meters per second and
thus yield nearly instantaneous information when echoing back. Radar
ranging is a two-way process that requires 12.36 micro-seconds for the
radio wave to travel out and back for each nautical mile of target range.
As shown in the distance illustration below, it takes 123.6 micro-seconds
for a transmitted pulse of radar energy to travel out and back from an
area of precipitation 10 nautical miles away.
10 NM
20 NM ROUND TRIP IN 123.6
MICROSECONDS