What is the type of propagation used by this antenna?
Answer – Near Vertical Incident Skywave (NVIS)
This aerial is ideal for use for communications between 5 and 650 km where groundwave propagation is not able to travel over mountainous terrain or through thick bush/jungle foliage. The concept was enhanced by Major John Shirley of the RNZ Signals attached to the Royal Signals during the Malayan Emergency to aid communications during jungle warfare. The aerial illustrated was not the one in use, but the concept was the same. Basically, the aerial had to be fairly close to the ground. so that the emission would radiate as close as possible to the vertical for the frequency selected.
HMNZS Irirangi used the above aerial design for the 8 and 3 MHz Coastal Common Net in the 1980s to enable ships in ports to the west and east coasts of NZ to communicate back to Waiouru. There was a groundwave component but this was quickly absorbed by the mountainous terrain.
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