One model, two radio calculations
A fictional radio worksheet specifies a propagation speed of 300 million metres per second. Its first part asks for wavelength at 150 megahertz. The second part gives a radar echo round-trip time of 20 microseconds, explicitly excluding processing delays, and asks for one-way target range. One learner uses the round-trip travel distance directly as range. Another mixes megahertz with hertz without changing the units. The exercise asks for the calculations and the reason for the factor of two. It supplies no real radar service volume, terrain, target reflectivity or minimum separation procedure. These ideal quantities support physical understanding rather than certify the accuracy or availability of a real navigation system. A correct answer should distinguish frequency, travel time and one-way distance and state each unit.
1. Calculate wavelength and one-way target range.
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Wavelength is 300,000,000/150,000,000=2 metres. Round-trip travel is 300,000,000×20×10⁻⁶=6,000 metres, so one-way target range is 3,000 metres.
2. Why is the range divided by two?
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The specified time includes the outward and return paths. One-way range is half the complete travel distance in this model; an actual transponder delay would require separate treatment if supplied.