Aerial grounding and QRM pick-up: theory & practice
 

"art" wrote
The most efficient radiator is one wave length long where
it is considered to be in equilibrium with a parallel electrical
cuircuit.

For most efficient radiation both the capacitance and the
inductance must act as a energy storage such that when
the terminals are shorted the energy is released in a burst
such that radiation can begin. ... In the case of a fractional
wave length radiator the pendulum type radiation is not
available for radiation
___________

Note (for one example of many) that in an antenna system consisting of a
1/2-wave, center-fed dipole driven by a matched, balanced transmission line,
the dipole itself radiates virtually all of the r-f energy present at the
antenna feedpoint.

The radiation efficiency of a system as in the above example, but using a
full wave dipole is no better than the 1/2-wave version, other things equal.
The full wave version just has a different radiation pattern.

RF

Aerial grounding and QRM pick-up: theory & practice
 

From a safety viewpoint all ground points are equal.
For _RF_ however, one ground point _may_ be better then another,
depending on how the wiring goes through the house, and where the ground
wire is picking up QRM, hence Richard's suggestion to feed the receiver
from a wall outlet in another room.
===================
Even better: If no AC is required but say 12 -14 V-DC , run the receiver
from a sealed lead-acid battery and only have a RF earth.

My complete station runs on 12V batteries (charged by 2 solar panels and
a wind gen) ,resulting in NO mains born interference .

If charging from mains ,one could switch-off charging while receiving
and only put charger on battery or batteries while transmitting.
however when the batteries are on the charger all the time the batteries
will probably 'absorb' any mains noise ; moreover the mains power supply
unit then does not need to supply peak current to the transmitter ,just
the average current which for a typical 100 W PEP transmitter (even with
compression) is not more than approx. 8 Amperes.
In such a situation the station will also always be available (for some
time) during a power outage ......emergency comms.

With batteries the supply voltage will on average be below 13.8 V ,hence
the transmitter output will be slightly lower resulting in a signal
which will be lower but never more than a small fraction of 1 S-point.

Note : When reducing power by a factor 2 the resulting signal will be
reduced by half 1 S-point.

Frank GM0CSZ / KN6WH

Aerial grounding and QRM pick-up: theory & practice
 

On Sat, 22 Sep 2007 16:05:39 +0100, Highland Ham
wrote:

Even better: If no AC is required but say 12 -14 V-DC , run the receiver
from a sealed lead-acid battery and only have a RF earth.

If charging from mains ,one could switch-off charging while receiving
and only put charger on battery or batteries while transmitting.

Hi Frank,

You are a proponent of one of my suggestions; yes, battery operation
(as I have as well) solves many issues.

My complete station runs on 12V batteries (charged by 2 solar panels and
a wind gen) ,resulting in NO mains born interference .
however when the batteries are on the charger all the time the batteries
will probably 'absorb' any mains noise ;

This is true only if the interfering voltage appears across the
battery - a rare occurrence unless you are mobile and speaking of
generator/alternator whine.

If batteries are float charged, then there is a path from the radio,
through the batteries, to the charger, to the mains and common mode
follows that path. Similar common mode paths of (in)convenience take
time to discover - like an external DSP powered by a wall-wart.

73's
Richard Clark, KB7QHC

Aerial grounding and QRM pick-up: theory & practice
 

On 22 Sep, 07:22, "Richard Fry" wrote:
"art" wrote

The most efficient radiator is one wave length long where
it is considered to be in equilibrium with a parallel electrical
cuircuit.
For most efficient radiation both the capacitance and the
inductance must act as a energy storage such that when
the terminals are shorted the energy is released in a burst
such that radiation can begin. ... In the case of a fractional
wave length radiator the pendulum type radiation is not
available for radiation

___________

Note (for one example of many) that in an antenna system consisting of a
1/2-wave, center-fed dipole driven by a matched, balanced transmission line,
the dipole itself radiates virtually all of the r-f energy present at the
antenna feedpoint.

The radiation efficiency of a system as in the above example, but using a
full wave dipole is no better than the 1/2-wave version, other things equal.
The full wave version just has a different radiation pattern.

RF

Aerial grounding and QRM pick-up: theory & practice
 

On 22 Sep, 07:22, "Richard Fry" wrote:
"art" wrote

The most efficient radiator is one wave length long where
it is considered to be in equilibrium with a parallel electrical
cuircuit.
For most efficient radiation both the capacitance and the
inductance must act as a energy storage such that when
the terminals are shorted the energy is released in a burst
such that radiation can begin. ... In the case of a fractional
wave length radiator the pendulum type radiation is not
available for radiation

___________

Note (for one example of many) that in an antenna system consisting of a
1/2-wave, center-fed dipole driven by a matched, balanced transmission line,
the dipole itself radiates virtually all of the r-f energy present at the
antenna feedpoint.

The radiation efficiency of a system as in the above example, but using a
full wave dipole is no better than the 1/2-wave version, other things equal.
The full wave version just has a different radiation pattern.

RF

I don't know what your credentials are for you to make such a
statement but it is a free world after all!
A quad radiator is a wave length radiator with a gain more than a half
wave as one sample.
Computor programing confirmes more radiation from full wave antennas
and mathematics according to Maxwell,s rules substantiate it. I can
understand not believing computor programs but I am very interested in
any mathematical data that would support your stand which is contrary
to the mathematics that I and others support.
What you are stating is that an attena in a series cuircit format
produces the same radiation as a parallel or tank cuircuit. I am more
than eager to read the contrary mathematical proof that is contrary to
the mathematics that I hold true. You may have hit on the true
explaqnation of radiation which Einstein, Planck and many others went
to their grave without solving it
Regards
Art KB9MZ.....XG

Aerial grounding and QRM pick-up: theory & practice
 

"art" wrote
A quad radiator is a wave length radiator with a gain more
than a half wave as one sample.

In your first post you wrote, "The most efficient radiator is one wave
length long where it is considered to be in equilibrium with a parallel
electrical cuircuit," and that is what I responded to.

Now you are writing about gain. Efficiency and gain are not synonymous.

Both of the dipole antennas in my previous post will radiate nearly 100% of
the r-f energy available from a matched, balanced source connected to their
input terminals. Therefore the radiation efficiency of those two
configurations does not favor the 1-wave over the 1/2-wave, which was your
opening premise.

They won't have the same gains in every direction, because their radiation
patterns are different. Same for your quad and "half wave" example.

RF

Aerial grounding and QRM pick-up: theory & practice
 

On 22 Sep, 12:33, "Richard Fry" wrote:
"art" wrote

A quad radiator is a wave length radiator with a gain more
than a half wave as one sample.

In your first post you wrote, "The most efficient radiator is one wave
length long where it is considered to be in equilibrium with a parallel
electrical cuircuit," and that is what I responded to.

Now you are writing about gain. Efficiency and gain are not synonymous.

Both of the dipole antennas in my previous post will radiate nearly 100% of
the r-f energy available from a matched, balanced source connected to their
input terminals. Therefore the radiation efficiency of those two
configurations does not favor the 1-wave over the 1/2-wave, which was your
opening premise.

They won't have the same gains in every direction, because their radiation
patterns are different. Same for your quad and "half wave" example.

RF

O.K. I may have muddied things. I hold to the fact that a one
wavelength dipole will always radiate at a higher efficiency than a
1/2 wave dipole. The example I gave as for an instance was a quad
versus a 1/2 wave dipole.
This is readily seen by any operator empirically. Mathematically it is
proven that way also even tho both are in accordance to Maxwell's
laws. You could I suppose compare a series antenna with a parallel
circuit i.e. a tank circuit that could reinforce your point and that
is what I hoped you would come up with to bolster your point without
resorting to a computor program based on Maxwellian laws. There is
much discussion about what creates radiation and I thought you may
have come up with something that we can all learn from. Eventually
even tho the past masters have died some one, possibly you, will
discover that which has eluded all, even quallified scientists with
huge resumes. I am willing to give you a hearing which does not often
happen on this newsgroupAs an aside I suspect that a single quad
element will beat a dipole anyway regardles of what the fields
differences that you point to but again I am very interested in any
mathematics that defends your possition possibly starting witha
parallel versus a series arrangement since it is very clear whatstarts
radiation in the parallelcase but unknown mathematically for the
series circuit.
Very best regards
Art Unwin....KB9MZ

Aerial grounding and QRM pick-up: theory & practice
 

On 22 Sep, 15:40, art wrote:
On 22 Sep, 12:33, "Richard Fry" wrote:





"art" wrote

A quad radiator is a wave length radiator with a gain more
than a half wave as one sample.

In your first post you wrote, "The most efficient radiator is one wave
length long where it is considered to be in equilibrium with a parallel
electrical cuircuit," and that is what I responded to.

Now you are writing about gain. Efficiency and gain are not synonymous.

Both of the dipole antennas in my previous post will radiate nearly 100% of
the r-f energy available from a matched, balanced source connected to their
input terminals. Therefore the radiation efficiency of those two
configurations does not favor the 1-wave over the 1/2-wave, which was your
opening premise.

They won't have the same gains in every direction, because their radiation
patterns are different. Same for your quad and "half wave" example.

RF

O.K. I may have muddied things. I hold to the fact that a one
wavelength dipole will always radiate at a higher efficiency than a
1/2 wave dipole. The example I gave as for an instance was a quad
versus a 1/2 wave dipole.
This is readily seen by any operator empirically. Mathematically it is
proven that way also even tho both are in accordance to Maxwell's
laws. You could I suppose compare a series antenna with a parallel
circuit i.e. a tank circuit that could reinforce your point and that
is what I hoped you would come up with to bolster your point without
resorting to a computor program based on Maxwellian laws. There is
much discussion about what creates radiation and I thought you may
have come up with something that we can all learn from. Eventually
even tho the past masters have died some one, possibly you, will
discover that which has eluded all, even quallified scientists with
huge resumes. I am willing to give you a hearing which does not often
happen on this newsgroupAs an aside I suspect that a single quad
element will beat a dipole anyway regardles of what the fields
differences that you point to but again I am very interested in any
mathematics that defends your possition possibly starting witha
parallel versus a series arrangement since it is very clear whatstarts
radiation in the parallelcase but unknown mathematically for the
series circuit.
Very best regards
Art Unwin....KB9MZ- Hide quoted text -

- Show quoted text -

Wait a minuit! you stated that a half wave antenna was nearly 100%
efficient and therein may be the true answer
A quad is often considered as two dipoles even tho there is only one
feed point thus efficiency per unit!Then one can refer to efficiency
per unit length. Is that your point?
Art

Aerial grounding and QRM pick-up: theory & practice
 

"art" wrote
O.K. I may have muddied things. I hold to the fact that a one
wavelength dipole will always radiate at a higher efficiency than a
1/2 wave dipole.
_________

Please post your definition of "efficiency," in this context.

RF

Aerial grounding and QRM pick-up: theory & practice
 

On 22 Sep, 16:02, "Richard Fry" wrote:
"art" wrote O.K. I may have muddied things. I hold to the fact that a one
wavelength dipole will always radiate at a higher efficiency than a
1/2 wave dipole.

_________

Please post your definition of "efficiency," in this context.

RF

Power in vs power out of a system. I know how to do this for a
parallel circuit ala
a tank circuit where energy is released in equilibrium fashion. For a
half wave dipole
you can't have two energy containers so you may or may not be heading
for excess end effects because of high voltage looking for where it
has to go. (Personally I don't know how a half wave radiates because
that form vuews the cyclic current continually radiating as the time
variant which is contrary to all other radiations i.e. a spark plug,
ahydregen bomb which is a bigger container that a flyback transformer
and a bigger container will always beat a small container with respect
to out going accelleration of energy, particles or plasma which ever
you may prefer)without any known proof.I believe that is why the quad
was designed to get away from the spark plug type emmissions at the
ends of the radiator.
On the other side of the coin, since both a quad and a 1/2 wave dipole
is assumed to be suitable drivers for a yagi array both must be bi
directional so gain is applicable when comparing these radiators I
would would think!
Best regards
Art