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[quote=YvesRoy]If, in a few years, Industry Canada would allow operate an AM transmitter more than 3 meters (let’s say a quarter of wavelength). In this case, with the same power (100 mW), how range will be with a quarter wavelength vertical antenna *WITH* 12 radials of 10 foot copper wire? And *WITH* 120 radials of a quarter wavelength?[/quote]
As always, MW “range” will depend on ground conductivity and path obstructions, quality of the receiving equipment, and interference levels at the receive site. But here are some general numbers based on the FCC’s propagation curves, and estimating that the system with 12 radials each 10 feet long will be about 10% as efficient as with 120 radials each 1/4-wave long…
Freq = 1,600 kHz
Ground conductivity = 8 mS/m
Radiator = 1/4-wave vertical monopole
Distance to 250 uV/m contour:
– using 120 buried radials each 1/4-wave long = 7.7 miles
– using 12 buried radials each 10 feet long = 3.8 miles
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