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Background:
Electronics technicians who
perform operations and maintenance for mine
warfare systems on board ships must sometimes
solve mathematical problems. Following are two
situations in which they are required to work
with formulas.
A dipole antenna is an antenna
that will resonate on a specific operating frequency.
When the antenna is resonant, it has better
sending and receiving properties. Technicians
use a formula to calculate how long the wire
in the antenna should be to optimize for the
frequency that's being used.
Technicians also use a formula
for radar, which is used to figure out the range
of a target on the radar display. The radar
signal propagates at the speed of light and
the time to travel to the object being detected,
then reflect off of it must be calculated. This
can be expressed as a constant in microseconds
[and can be used for determining ranges in nautical
miles. This answers the question: how far away
is the object being detected?
You are an electronics technician
on a ship involved in mine warfare.
Problem A:
Use the formula for a wave
dipole antenna using 14-gauge wire
lengthft= 468
ft / fMHz
to calculate the length in
feet for the frequency 1.7 GHz
fMHz = frequency in megahertz
1 GHz = 1,000 MHz
1 ft = 12 inches
GHz = gigahertz
Hertz is cycles per second.
Problem B:
Use the formula for Radar range
(Nautical miles) = Elapsed time/12.36 mS
Microsecond = 1 millionth
of 1 second
mS = microseconds
If the elapsed time for the
return pulse (echo) is 61.8 mS, what is the
range of the target?
The solution
to this problem is included in the problem
file, available for downloading.
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