1. What is a “radar mile?”
c) 12.36 µs
A radar mile is the time required for a signal leaving
the antenna to go out and back one nautical mile (6076 feet). 2 * 6076 ft / [9.8356e8 ft/s] = 12.36 µs
2. Which best describes a bi-static radar?
a) Fixed transmitter and fixed receiver at
Many bi-static systems use multiple receiving sites to be able to pick up weaker reflected
signals and to correlate position information with more certainty.
3. What is a radar
b) A target’s reflecting capacity equivalent to a perfectly reflecting surface of
the same area
For radar evasion (stealth), a low RCS is desirable. To guarantee being detected (general & commercial
aviation, a high RCS is desirable. A B-52 bomber has an RCS of about 100 m2
(20 dBsm, whereas an
F-117 Stealth Fighter has about a 0.003 m2
RCS (which at X-band puts it in the realm of birds).
4. What are common units of radar cross-section (RCS)?
Decibels relative to a square
5. Who is known as ”The Father of Radar?”
a) Robert Watson-Watt
Watson-Watt, with the help of his assistant Arnold Wilkins, drafted, in February 1935, a report titled "The
Detection of Aircraft by Radio Methods." Walter Eugene O'Reilly was "Radar" from the television show M*A*S*H.
6. Which flying (movement) condition will always result in a Doppler speed of 0 m/s?
Perfect concentric circle around antenna at constant altitude
Doppler speed is manifested on the
boresight radial line (main radiation lobe) so, neglecting “blind speeds,” the only way to be moving and have
the Doppler speed at 0 m/s is to not have any motion relative to the boresight radial line.
What does “MTI” stand for?
c) Moving Target Indication
Moving Target Indication (MTI) uses a cancellation
system that blanks
out stationary targets to permit only moving targets to be displayed on the display. Doing so greatly reduces
the clutter and allows relatively weak moving targets to be seen in the midst of buildings, trees, etc.
8. Synthetic Aperture Radar (SAR) radar is mostly likely to be located on which platform?
Synthetic Aperture Radar (SAR) relies on the motion of the platform to produce the “scan” that would
otherwise be provided by a rotating or steerable antenna.
9. Which feature of a “stealth”
aircraft is most responsible for its low observability?
b) Multi-faceted surfaces
The angle of a
signal’s reflection form a surface is equal to the angle of its incidence on the surface. By minimizing the area
presented perpendicular to any given direction (particularly those direction most likely to be illuminated, like
from below and the side), a minimum amount of incident radar signal energy will be reflected back in the
direction from which it originated (the radar).
10. What kind of radar did the webmaster of RF
Cafe work on while in the U.S.A.F?
In the U.S. government system designation standard, the "M" stands for ground Mobile, the
"P" stands for Radar, and the "N" stands for Navigational aides. The "-14" designates position in a series.