APPENDIX C INTERPRETING RADAR IMAGES
(D) Ducted echoes from long-range targets
An atmospheric phenomenon
known
as a radio-wave duct can be caused by air at high temperature
and humidity. Radar waves can propagate over abnormally-long distances in such a duct. In such a
case, long-range targets may appear as
if they are at close range. This is attributable to the fact that
the echo from a long-distance target is delayed beyond the transmission repetition cycle so the echo
appears in the next cycle. These ducted echoes disappear when
the range is switched so they can be
recognized
easily.
C.5 Radar Interference
When another radar is operating nearby at the same frequency, the transmitted radar pulses
from the
other radar may appear on your screen as interference. The form of the interference is not constant
but usually
it takes the form of curves or random interference. When the radar interference suppres-
sion
ON/OFF key of this radar is not preset, the radar
interference
suppression function operates
continuously.
58
To Next Page
Loading...