User's Manual

Synapsis Radar
with Nautoscan NX Pedestal
Operator Manual
4265.DOC020102
3-10
Edition July 2015
3.2.1.4 Second trace false echo
The second trace false echo appears when the signal is received at the next
pulse repetition period after it was reflected by a high mountain or similar object
in long distance. Therefore, the position in which it appears is identified by
subtracting distance corresponding to the pulse repetition interval from the
actual distance. Assuming the pulse period is 1000 μs and the range scale is
adjusted tor 12 NM, the pulse reflected from a target 80 NM away returns after
1000 μs. Targets lying at a distance of beyond (80 NM + 12 NM=) 92 NM,
therefore, can generate second trace false echoes.
A target in 83 NM distance may generate an echo on the Radar display at 3 NM
(Figure 3-7).
Figure 3-7 Second Trace False Echo Effect
Second trace false echo
Transmit pulse
2
Transmit pulse
1
Echo from
transmit pulse
1
Range
scale 3 NM
1/pulse repetition frequency
with 1000/s approx. 80 NM
Range
scale 12
NM
Pulse period