Everything you want to know about antennae ....
 

"Wayne" wrote in message
...

There has previously on the newsgroup been a claim that shortness makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie to
your claim.

Everything you want to know about antennae ....
 

"gareth G4SDW GQRP #3339" wrote in message
...

"Wayne" wrote in message
...

There has previously on the newsgroup been a claim that shortness makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie to
your claim.

In my claim, equal power arrives at the long or short antenna AFTER the
ohmic resistances have already occurred.

Doesn't matter if you need 2000 watts to deliver 100 watts to the short
antenna.

My understanding is that you claim the short antenna is inefficient only
because it is short.

Everything you want to know about antennae ....
 

In rec.radio.amateur.antenna gareth G4SDW GQRP #3339 wrote:
"Wayne" wrote in message
...

There has previously on the newsgroup been a claim that shortness makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie to
your claim.

I make all my short antennas out of superconductors so they do not have
ohmic resistance.

--
Jim Pennino

Everything you want to know about antennae ....
 

"Wayne" wrote:
"gareth G4SDW GQRP #3339" wrote in message ...

"Wayne" wrote in message
...

There has previously on the newsgroup been a claim that shortness makes inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100 watts.
Different patterns, but the power radiated is the same, if you manage
to successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie to your claim.

In my claim, equal power arrives at the long or short antenna AFTER the
ohmic resistances have already occurred.

Doesn't matter if you need 2000 watts to deliver 100 watts to the short antenna.

My understanding is that you claim the short antenna is inefficient only
because it is short.

Wayne, you're wasting your breath. You'll never get Gareth to see sense on
this. He's been banging this drum for years now.


--
STC // M0TEY // twitter.com/ukradioamateur

Everything you want to know about antennae ....
 

"Wayne" wrote in message
...
"gareth G4SDW GQRP #3339" wrote in message
...
"Wayne" wrote in message
...
There has previously on the newsgroup been a claim that shortness makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie to
your claim.

In my claim, equal power arrives at the long or short antenna AFTER the
ohmic resistances have already occurred.

I don't know what you mean by that. The Ohmic resistances to which I
referred
were those of the antenna rod itself.

Everything you want to know about antennae ....
 

On 02/24/2016 12:19 AM, Richard Fry wrote:
"Wayne" wrote

Dead on explanation. Some have insisted that inefficiencies
result from antenna size and not from matching challenges.
_______

Kindly note that the radiation efficiency of an antenna _system_ is
related to its radiation resistance compared to other resistive losses
present in that antenna system.

It is possible to perfectly match the impedance at the feedpoint of an
antenna system to the impedance of the transmission line connected
there. But that antenna system still can have very poor radiation
efficiency at that frequency.

An example of this is a Z-matched, but electrically short vertical
monopole driven against a poor r-f ground connection such as a few
buried ground rods. Most of the available transmitter power is
dissipated in the r-f ground resistance, rather than being usefully
radiated as e-m waves.
===============================
That all depends on the length of the antenna against the operating
frequency .
A half wave vertical has a high RF voltage at its "bottom" but a low RF
current at that point ,hence less ground loss ,meaning that not all that
many radials are required compared with a quarter wave vertical .
Of course an impedance transformer is required .
A well known transformer is an inductor of 14 windings between ground
and vertical antenna and over it one of 2 windings connected to the
feeder and hence transmitter ,resulting in a 1:7 voltage transformation
,hence a 1: 49 (say 50) impedance transformation . Across the 14
windings is a HV variable capacitor to adjust for minimal SWR.

A well known matching circuit (tuner if you wish) used for low power HF
ARDF transmitters is the L-circuit by G3ZOI
Here the low impedance of the transmitter's output is in series with a
variable capacitor the other side connected to the(high impedance) short
wire antenna and to a grounded inductor . With 2 diodes in series with a
LED in de output to the antenna the LED is adjusted for max RF current
(max LED brightness). For 1-5 W transmitters the variable capacitor can
be a polyvarcon type from a portable MW receiver ....works very well !

Frank GM0CSZ / KN6WH in IO87AT

Everything you want to know about antennae ....
 

On 2/29/2016 1:42 PM, gareth G4SDW GQRP #3339 wrote:
"Wayne" wrote in message
...
"gareth G4SDW GQRP #3339" wrote in message
...
"Wayne" wrote in message
...
There has previously on the newsgroup been a claim that shortness makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie to
your claim.

In my claim, equal power arrives at the long or short antenna AFTER the
ohmic resistances have already occurred.

I don't know what you mean by that. The Ohmic resistances to which I
referred
were those of the antenna rod itself.

All practical antenna have ohmic resistance. None are perfectly
efficient. You can design any antenna to have any efficiency you wish
by using suitable materials even if you have to use superconductors.

--

Rick

Everything you want to know about antennae ....
 

"rickman" wrote in message ...

On 2/29/2016 1:42 PM, gareth G4SDW GQRP #3339 wrote:
"Wayne" wrote in message
...
"gareth G4SDW GQRP #3339" wrote in message
...
"Wayne" wrote in message
...
There has previously on the newsgroup been a claim that shortness makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage
to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie
to
your claim.

In my claim, equal power arrives at the long or short antenna AFTER the
ohmic resistances have already occurred.

I don't know what you mean by that. The Ohmic resistances to which I
referred
were those of the antenna rod itself.

# All practical antenna have ohmic resistance. None are perfectly
# efficient. You can design any antenna to have any efficiency you wish
# by using suitable materials even if you have to use superconductors.

I gave up. If we are talking about theoretical antennas, they are lossless.

Everything you want to know about antennae ....
 

In rec.radio.amateur.antenna Wayne wrote:


"rickman" wrote in message ...

On 2/29/2016 1:42 PM, gareth G4SDW GQRP #3339 wrote:
"Wayne" wrote in message
...
"gareth G4SDW GQRP #3339" wrote in message
...
"Wayne" wrote in message
...
There has previously on the newsgroup been a claim that shortness makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage
to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie
to
your claim.

In my claim, equal power arrives at the long or short antenna AFTER the
ohmic resistances have already occurred.

I don't know what you mean by that. The Ohmic resistances to which I
referred
were those of the antenna rod itself.

# All practical antenna have ohmic resistance. None are perfectly
# efficient. You can design any antenna to have any efficiency you wish
# by using suitable materials even if you have to use superconductors.

I gave up. If we are talking about theoretical antennas, they are lossless.

Theoretical antennas have whatever loss you assign to them.


--
Jim Pennino

Everything you want to know about antennae ....
 

wrote in message ...

In rec.radio.amateur.antenna Wayne wrote:


"rickman" wrote in message ...

On 2/29/2016 1:42 PM, gareth G4SDW GQRP #3339 wrote:
"Wayne" wrote in message
...
"gareth G4SDW GQRP #3339" wrote in message
...
"Wayne" wrote in message
...
There has previously on the newsgroup been a claim that shortness
makes
inefficiency.
To that I say that if for example, 100 watts is fed to a resonant HF
dipole, and 100 watts is fed to a 1 foot long dipole, both radiate 100
watts.
Different patterns, but the power radiated is the same, if you manage
to
successfully get the power to the antenna.

The ratio of radiation resistance to ohmic resistance will give the lie
to
your claim.

In my claim, equal power arrives at the long or short antenna AFTER the
ohmic resistances have already occurred.

I don't know what you mean by that. The Ohmic resistances to which I
referred
were those of the antenna rod itself.

# All practical antenna have ohmic resistance. None are perfectly
# efficient. You can design any antenna to have any efficiency you wish
# by using suitable materials even if you have to use superconductors.

I gave up. If we are talking about theoretical antennas, they are
lossless.

# Theoretical antennas have whatever loss you assign to them.

And lossless is a good way to get down to basics.