Technician › T3
T3 Radio Wave Propagation
35 questions in the pool. Your exam will include 3, one from each group below.
T3A
Radio wave characteristics: how a radio signal travels, fading, multipath, polarization, wavelength vs absorption; Antenna orientation
- T3A01Why do VHF signal strengths sometimes vary greatly when the antenna is moved only a few feet?
- T3A02How does vegetation affect UHF and microwave signals?
- T3A03What antenna polarization is normally used for long-distance CW and SSB contacts on the VHF and UHF bands?
- T3A04What is the effect of antenna cross-polarization over a line-of-sight VHF or UHF path?
- T3A05When using a directional antenna, how might your station be able to communicate with a distant repeater if buildings or obstructions are blocking the direct line of sight path?
- T3A06What is the meaning of the term “picket fencing”?
- T3A07What weather condition might decrease range at microwave frequencies?
- T3A08What is a likely cause of irregular fading of signals propagated by the ionosphere?
- T3A09Which of the following results from the fact that signals propagated by the ionosphere are elliptically polarized?
- T3A10What effect does multi-path propagation have on data transmissions?
- T3A11Which region of the atmosphere can reflect HF radio waves?
- T3A12What effect does fog or rain have on 10-meter and 6-meter band signals?
T3B
Electromagnetic wave properties: wavelength vs frequency, nature and velocity of electromagnetic waves, relationship of wavelength and frequency; Electromagnetic Spectrum Definitions: UHF, VHF, HF
- T3B01What is the relationship between the electric and magnetic fields of an electromagnetic wave?
- T3B02What property of a radio wave defines its polarization?
- T3B03What are the two components of a radio wave?
- T3B04What is the velocity of a radio wave traveling through free space?
- T3B05What is the relationship between wavelength and frequency?
- T3B06What is the formula for converting frequency to approximate wavelength in meters?
- T3B07In addition to frequency, which of the following is used to identify amateur radio bands?
- T3B08What frequency range is referred to as VHF?
- T3B09What frequency range is referred to as UHF?
- T3B10What frequency range is referred to as HF?
- T3B11What is the approximate velocity of a radio wave in free space?
- T3B12Which of these frequencies travels at the highest velocity in free space?
T3C
Propagation modes: sporadic E, meteor scatter, auroral propagation, tropospheric ducting; F region skip; Line of sight and radio horizon
- T3C01Why are simplex UHF signals rarely heard beyond their radio horizon?
- T3C02What is a characteristic of HF communication compared with communications on VHF and higher frequencies?
- T3C03What is one characteristic of VHF signals received via auroral backscatter?
- T3C04Which of the following types of propagation is most commonly associated with occasional strong signals on the 10-, 6-, and 2-meter bands from beyond the radio horizon?
- T3C05Which of the following effects may allow radio signals to travel beyond obstructions between the transmitting and receiving stations?
- T3C06What type of propagation is responsible for allowing over-the-horizon VHF and UHF communications to ranges of approximately 300 miles on a regular basis?
- T3C07What band is best suited for communicating via meteor scatter?
- T3C08What causes tropospheric ducting?
- T3C09What is generally the best time for long-distance 10-meter band propagation via the F region?
- T3C10Which of the following bands may provide long-distance communications via the ionosphere's F region during the peak of the sunspot cycle?
- T3C11Why is the radio horizon for VHF and UHF signals more distant than the visual horizon?