Hi All,
When Andy queried the formulae yesterday, I later recalled the article in the
first edition of the LF Experimenters Source Book, by Lloyd Butler, VK5BR,
where he states:
1. The electric component of the induction field decreases with the cube of the
distance and dB = 60log(d2/d1), where d2 and d1 are the relative distances.
2. The magnetic component of the induction field decreases with the square of
the distance and dB = 40log(d2/d1).
3. Both the electric and magnetic components of the radiation field decrease
directly with distance and dB = 20log(d2/d1).
A graph is included in the article, showing the magnetic component of the
induction field to be greater than the electric at distances of 0.1 of a
wavelength.
So for distances from about 3 to 5 kilometres the electric component of the
induction field can be ignored but the magnetic component of the induction
field is still significant.
So it seems likely that a loop receive antenna should enable the unofficial
record to be increased.
73, John, G4CNN
email: [email protected]
web page: http://www.g4cnn.f2s.com
Question to Andy: Would it help or hinder your case if others were also to
apply for an NOV for 9kHz?
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