Short antennae - a reprise
 

gareth wrote:
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?

Why do you have this compulsion to post utter nonsense, gas bag?

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

They are not the "two major ways", they are the only two ways.

It is easier for us to model things as though they were resistances, even if
they were not.

No, it is not; it makes no difference.

(By the same token is the BJT modelled as a combination of resistances,
capacitances
and current generators)

Gas bag babble.

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.

Nope, the radiation resistance is the result of the model. Once again
you have the cart and horse reversed.

In terms of the resistance model, that so-called radiation resistance
behaves as though it

There is no "resistance model", gas bag.

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.

Yet more gas bag babble and poor logic based on a false premise.




--
Jim Pennino

Short antennae - a reprise
 

gareth wrote:

If short antennae radiate all the power that is fed to them, then why
would anyone use long antennae,

Because there may be factors other than power efficiecny that are important
to the designer. For example, radiation pattern.


because the first part of such an antenna,
the short
part, would radiate all the power, and then there'd be nothing left for
the extra bit, making up the rest of the long antenna, to do?


Unfortunately, only you belive that is the case. Your position conflicts
with what is understood about antennas.

The answer is, of course, because it is more difficult to feed a short
antenna
because of its reactance.


That may be one reason for using a longer antenna. It is not the only
reason, nor may it be the primary reason.

So, whence does this reactance arise?

Simple.

It is the power that has NOT been all radiated by the short antenna
arriving back at
the feed point with an awkward phase relationship with the incident power.

What happens to that power that has not ALL been radiated when it arrives
back
at the feed point?

Simple.

It passes back into the matching network, which, together with the short
bit, form
the resonant artefact, where much of it disappears as heat in the matching
network
before being fed back to the short antenna to start all over again.

If it is so simple, where are the equations and models that describe it?

Short antennae - a reprise
 

gareth wrote:
wrote in message
...
And it is not the "apparent radiation resistance " it is the real,
calculable,
and measurably radiation resistance, you gas bag.

Lo! And behold! When you calculate it, one of the terms is the ratio
between antenna length and wavelength

Therefore it is not "apparent radiation resistance" as you said, it is
real and calculable as I said, gas bag.



--
Jim Pennino

Short antennae - a reprise
 

wrote in message
...
Why do you have this compulsion to post utter nonsense, gas bag?

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

They are not the "two major ways", they are the only two ways.

It is easier for us to model things as though they were resistances, even
if
they were not.

No, it is not; it makes no difference.

(By the same token is the BJT modelled as a combination of resistances,
capacitances
and current generators)

Gas bag babble.

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.

Nope, the radiation resistance is the result of the model. Once again
you have the cart and horse reversed.

In terms of the resistance model, that so-called radiation resistance
behaves as though it

There is no "resistance model", gas bag.

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.

Yet more gas bag babble and poor logic based on a false premise.




--
Jim Pennino

Short antennae - a reprise
 

wrote in message
...

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

They are not the "two major ways", they are the only two ways.

There are also the dielectric and permeability losses associated
with the creation and collapse of the near fields.


Interesting that in Yankland you prefer to be known as Hams, because
it is now apparetn that you cannot educate pork.

Short antennae - a reprise
 

wrote in message
...
gareth wrote:
wrote in message
...
And it is not the "apparent radiation resistance " it is the real,
calculable,
and measurably radiation resistance, you gas bag.

Lo! And behold! When you calculate it, one of the terms is the ratio
between antenna length and wavelength

Therefore it is not "apparent radiation resistance" as you said, it is
real and calculable as I said, gas bag.

You continue to represent yourself as a 5-year-old.

It is not a real resistance, for, if it were, then the power would be
dissipated as heat
and not as radiation.

Short antennae - a reprise
 

gareth wrote:
wrote in message
...

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

They are not the "two major ways", they are the only two ways.

There are also the dielectric and permeability losses associated
with the creation and collapse of the near fields.

For dielectric antennas which you have never shown any interest in
gas bagging about and your stated reason why it exists is yet more
hot air nonsense.

Interesting that in Yankland you prefer to be known as Hams, because
it is now apparetn that you cannot educate pork.

Interesting that you are such a gas bag full of so much hot air.

Do the titled invite you to their old mansions in the winter to save
on heating costs?


--
Jim Pennino

Short antennae - a reprise
 

gareth wrote:
wrote in message
...
gareth wrote:
wrote in message
...
And it is not the "apparent radiation resistance " it is the real,
calculable,
and measurably radiation resistance, you gas bag.

Lo! And behold! When you calculate it, one of the terms is the ratio
between antenna length and wavelength

Therefore it is not "apparent radiation resistance" as you said, it is
real and calculable as I said, gas bag.

You continue to represent yourself as a 5-year-old.

You continue to represent yourself as a bloviating gas bag.

It is not a real resistance, for, if it were, then the power would be
dissipated as heat
and not as radiation.

What part of real, calculable, and measurable RADIATION RESISTANCE did
you not understand, gas bag?

Have you become so loony you can not understand the difference between
"resistance" and "radiation resistance", gas bag?


--
Jim Pennino

Short antennae - a reprise
 

wrote in message
...
For dielectric antennas which you have never shown any interest in
gas bagging about and your stated reason why it exists is yet more
hot air nonsense.
Interesting that you are such a gas bag full of so much hot air.
Do the titled invite you to their old mansions in the winter to save
on heating costs?

Grow up, child.

Short antennae - a reprise
 

wrote in message
...
You continue to represent yourself as a bloviating gas bag.
What part of real, calculable, and measurable RADIATION RESISTANCE did
you not understand, gas bag?
Have you become so loony you can not understand the difference between
"resistance" and "radiation resistance", gas bag?

Grow up, child.