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Old October 14th 14, 07:52 AM posted to rec.radio.amateur.antenna
AndyW AndyW is offline
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Default Short antenna = reduced power

On 13/10/2014 09:15, gareth wrote:
Quoting from Electromagnetism
By F.N.H.Robinson
in the Oxford Physics Series
1973 edition
ISBN 0 19 8518913
Chapter 11, Radiation,
page 102
Formula 11.11

Has in the equation for radiated power the term

(2*PI*L/LAMBDA)**2

where L is the antenna length and LAMBDA the wavelength,
thereby showing that the radiated power decreases when the
antenna length decreases.

I will read up further and report further...


Something is missing here, I suspect that you have not quoted all the
formulae as this does not make sense in isolation.
ISTR from my Electromagnetics that there is a polynomial relationship
and not a linear relationship. It produces peaks of radiated power as
the length of the apparent radiator approaches the point where wave
superposition occurs.

Can you give more context?

However it has been a while since antenna theory and electromagnetism;
about 30 years so it is likely that I have forgotten a lot.

Andy