A radiating feedline can cause TVI by radiating closer to the faulty TV
than the elevated and relatively remote antenna. In some areas, the
neighbor's TVs aren't very far from the ham station. There is a
difference between harmonics and fundamental overload. Both are affected
by feedline radiation. We tend to attack harmonics by low pass filters
on the transmitter and high pass filters on the affected TV, rather than
band pass filters. Sometimes harmonics are generated in overloaded TV RF
stages.
73, Jerry, K0CQ
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Entire content copyright Dr. Gerald N. Johnson, electrical engineer.
Reproduction by permission only.
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