NZART Amateur Examination                     page 9          NZARTX07 Security code 264678
- Insulators are used at the end of suspended antenna
wires to:
- increase the effective antenna length
- limit the electrical length of the antenna
- make the antenna look more attractive
- prevent any loss of radio waves by the antenna
- At the ends of a half-wave dipole the:
- voltage and current are both high
- voltage is high and current is low
- voltage and current are both low
- voltage low and current is high
- Because of high absorption levels at frequencies below
4 MHz during
daylight
hours, only high angle signals are normally reflected back by
this layer:
- C
- D
- E
- F
- Signal fadeouts resulting from an 'ionospheric storm' or
'sudden
ionospheric
disturbance' are usually attributed to:
- heating of the ionised layers
- over-use of the signal path
- insufficient transmitted power
- solar flare activity
- The skip distance of radio signals is determined by the:
- type of transmitting antenna used
- power fed to the final amplifier of the transmitter
- only the angle of radiation from the antenna
- both the height of the ionosphere and the angle of
radiation from the
antenna
- The position of the E layer in the ionosphere is:
- above the F layer
- below the F layer
- below the D layer
- sporadic
- Reception of high frequency radio waves beyond 4000
km normally
occurs by
the:
- ground wave
- skip wave
- surface wave
- sky wave
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