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Old November 4th 14, 09:11 PM posted to rec.radio.amateur.antenna
gareth gareth is offline
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First recorded activity by RadioBanter: Sep 2012
Posts: 1,382
Default Short antennae - a reprise

wrote in message
...
gareth wrote:
wrote in message
...

The answer is because the radiation resistance is measured in milliohms
and a matching network to match 50 Ohms to milliohms has huge resistive
losses.


Afraid you've just shot yourself in the foot, there, Old Chap, because
the
reason that the apparent radiation resistance is so low is because so
little
is radiated!


And it is not the "apparent radiation resistance " it is the real,
calculable,
and measurably radiation resistance, you gas bag.


Why do you have this compulsion to shout out insults in the manner of a
5-year-old?

There are two major ways in which the power is dissipated. One is radiation,
and the
other is the i2r losses in the metal.

It is easier for us to model things as though they were resistances, even if
they were not.
(By the same token is the BJT modelled as a combination of resistances,
capacitances
and current generators)

So, the power that is dissipated as radiation is modelled as though it is a
resisitance, although
it is not a resistance, but a mechanism by which power is dissipated.

In terms of the resistance model, that so-called radiation resistance
behaves as though it
is a resistance in series with the resistance of the wire, and it matters
not what current you
manage to force into the antenna, as the antenna shortens, and the apparent
radiation
resistance decreases, the i2r losses start to dominate, and therefore the
short antenna
is a poor radiator in not radiating all the power fed to it.