Checkpoint: T3A — HAM Trainer

T3A01 Why do VHF signal strengths sometimes vary greatly when the antenna is moved only a few feet?

A The signal path encounters different concentrations of water vapor B VHF ionospheric propagation is very sensitive to path length C Multipath propagation cancels or reinforces signals D The Doppler effect causes slight frequency shifts which result in changes in signal strength

T3A02 How does vegetation affect UHF and microwave signals?

A Causes knife-edge diffraction, distorting voice peaks B Absorbs signals, leading to poor reception of weak signals C Amplifies signals, improving reception of weak signals D Has no effect

T3A03 What antenna polarization is normally used for long-distance CW and SSB contacts on the VHF and UHF bands?

A Right-hand circular B Left-hand circular C Horizontal D Vertical

T3A04 What is the effect of antenna cross-polarization over a line-of-sight VHF or UHF path?

A Modulation sidebands might become inverted B Received signal strength is reduced C Signals have an echo effect D Nothing significant will happen

T3A05 When 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?

A Change from vertical to horizontal polarization B Try to find a path that reflects signals to the repeater C Try the long path D Increase the antenna SWR

T3A06 What is the meaning of the term "picket fencing"?

A Alternating transmissions during a net operation B Rapid flutter on mobile signals due to multipath propagation C A type of ground system used with vertical antennas D Interference from cable TV in the form of carriers at fixed intervals across the band

T3A07 What weather condition might decrease range at microwave frequencies?

A High winds B Low barometric pressure C Precipitation D Colder temperatures

T3A08 What is a likely cause of irregular fading of signals propagated by the ionosphere?

A Frequency shift due to Faraday rotation B Interference from thunderstorms C Intermodulation distortion D Random combining of signals arriving via different paths

T3A09 Which of the following results from the fact that signals propagated by the ionosphere are elliptically polarized?

A Digital modes are unusable B Either vertically or horizontally polarized antennas may be used for transmission or reception C FM voice is unusable D Both the transmitting and receiving antennas must be of the same polarization

T3A10 What effect does multi-path propagation have on data transmissions?

A Transmission rates must be increased by a factor equal to the number of separate paths observed B Transmission rates must be decreased by a factor equal to the number of separate paths observed C No significant changes will occur if the signals are transmitted using FM D Error rates are likely to increase

T3A11 Which region of the atmosphere can reflect HF radio waves?

A The stratosphere B The troposphere C The ionosphere D The electrosphere

T3A12 What effect does fog or rain have on 10-meter and 6-meter band signals?

A Absorption B Little effect C Deflection D Increased range