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Question 25.1: A signal has a frequency of 400 MHz. It is to be carried by ...

A signal has a frequency of 400 MHz. It is to be carried by a cable with a length of 15 ft. Is the cable a transmission line?

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\lambda =300/f_{MHZ}= 300/400=0.75 m

The cable is 15 ft long. With 3.28 feet per meter, the length in meters is 15/3.28 = 4.573 m.

If the wavelength of the signal is one-tenth or less of the cable length, the cable is a transmission line.

One-tenth of 4.573 m is 0.4573 m. The cable is definitely a transmission line.

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