RF PREP // FCC AMATEUR RADIO

T3 · Radio Wave Propagation

Technician · correct answers only, in question-pool order.

T3A01

Why do VHF signal strengths sometimes vary greatly when the antenna is moved only a few feet?

AnswerMultipath propagation cancels or reinforces signals.

Reflected VHF signals can arrive by several paths. Depending on phase, those copies may reinforce one another or partially cancel.

T3A03

AnswerHorizontal.

Weak-signal VHF/UHF CW and SSB activity normally uses horizontal polarization, unlike most local FM mobile and repeater work.