BasicB-006-004-004
As the length of a transmission line is changed, what happens to signal loss?
C
Answer
Antennas and feed lines
Type
A
Signal loss decreases as the length increases
B
Signal loss is the same for any length of transmission line
C
Signal loss increases as the length increases
D
Signal loss is the least when the length is the same as the signal's wavelength
Answer Notes
Transmission lines, such as coaxial cable or ladder line, have a certain amount of inherent resistance and dielectric loss per unit of length. Because these losses are cumulative, making the cable longer means more of the signal's energy is converted into heat before it reaches the antenna.
Therefore, signal loss always increases as the length of the transmission line increases. Distractors suggesting that loss decreases with length or depends on matching the signal's wavelength confuse basic line attenuation with antenna resonance or standing wave nodes.
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If your transmitter and antenna are 15 metres apart, but are connected by 60 metres of RG-58 coaxial cable, what should be done to reduce transmission line loss?
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As the frequency of a signal is changed, what happens to signal loss in a transmission line?