"Quarter wave ground mounted radials are a waste of wire."
 

I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

What say you all?

"Quarter wave ground mounted radials are a waste of wire."
 

we all agree of course!

"Rick (W-A-one-R-K-T)" wrote in message
.. .

I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

What say you all?

"Quarter wave ground mounted radials are a waste of wire."
 

Rick (W-A-one-R-K-T) wrote:
"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

What say you all?

The ground does detune ground
mounted radials because the fields are attenuated by the
ground. Twice as many 1/8WL buried radials may work as well
or better than half as many 1/4WL buried radials.
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

On Sun, 23 Sep 2007 12:46:30 -0400, "Rick (W-A-one-R-K-T)"
wrote:
What say you all?

Hi Rick,

Sounds like the ghost of Reggie.

So, in honor to his aphorisms and homilies, it should be noted that
adding more wire to that which is conducting nearly nothing - is a
waste of wire.

If we are to reduce this to sound-bites, then the taller the radiator,
the longer the radial(s). If I recall Reggie's other homilies
correctly, there should be a one-to-one correlation (length=height).
As far as efficiency goes, the difference between 20 radials and 120
is hardly noticeable on the S-Meter. Real engineers can measure
differences, but they are far and few between (and don't QSO).

73's
Richard Clark, KB7QHC

"Quarter wave ground mounted radials are a waste of wire."
 

"Rick wrote

... What say you all?

Read "Ground Systems as a Factor in Antenna Efficiency" by Brown, Lewis &
Epstein of RCA Labs, published in the June, 1937 issue of The Proceedings of
the I.R.E.

It proves otherwise.

RF

"Quarter wave ground mounted radials are a waste of wire."
 

"Rick (W-A-one-R-K-T)" wrote in message
.. .

I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

What say you all?

Hi Rick

I have just tried an HF 80 metre ground mounted quarter wave vertical in
exactly the conditions you describe. The screen of the coax feedline is
grounded at the base of the antenna with a copper earth rod into very
conductive ground (effectively wet sand). The antenna impedence and
performance appeared identical whether or not quarter wave radials were
attached or not.

At a previous location with less conductive soil the radials did make a
difference.

A couple of quarter wave radials can certainly be effective and easier to
run out than a multitude of shorter wires circling the antenna. As usual it
all depends on the local conditions at your location and what you have
available to work with.

Mike G0ULI

"Quarter wave ground mounted radials are a waste of wire."
 

On Sun, 23 Sep 2007 12:59:49 -0500, Richard Fry wrote:

"Rick wrote

... What say you all?

Read "Ground Systems as a Factor in Antenna Efficiency" by Brown, Lewis
& Epstein of RCA Labs, published in the June, 1937 issue of The
Proceedings of the I.R.E.

It proves otherwise.

Honest question, does it matter whether the objective is a strong ground
wave as in AM broadcast or skywave as in amateur operation?

I am installing a Hustler 4BTV this fall and have put down (so far) 16
radials that range from about 18 to 35 feet in length due to my servere
space restrictions. I may add 16 more later this fall as an experiment.

73, de Nate

--

"The optimist proclaims that we live in the best of all possible worlds,
the pessimist fears this is true."

"Quarter wave ground mounted radials are a waste of wire."
 

On Sep 25, 4:53 pm, Nate Bargmann
wrote:
On Sun, 23 Sep 2007 12:59:49 -0500, Richard Fry wrote:
"Rick wrote

... What say you all?

Read "Ground Systems as a Factor in Antenna Efficiency" by Brown, Lewis
& Epstein of RCA Labs, published in the June, 1937 issue of The
Proceedings of the I.R.E.

It proves otherwise.

Honest question, does it matter whether the objective is a strong ground
wave as in AM broadcast or skywave as in amateur operation?

No, the local ground losses effect the efficiency the same no matter
what skip type,
angles used , etc..
It will be equally weaker in all directions and angles if you add more
ground loss.
The pattern will still be the same in all directions, as all angles
suffer equally.
Same pattern, just less field strength if you add more ground loss.
MK

"Quarter wave ground mounted radials are a waste of wire."
 

"Nate Bargmann" wrote
Honest question, does it matter whether the objective is a
strong ground wave as in AM broadcast or skywave as in
amateur operation?
______

Hi, Nate -

The skywave is important not only to amateur operators, but even more so to
the nighttime coverage of stations designated by the FCC as Class A AM
broadcast stations (the former "clear channel" stations).

However a poor r-f ground system for a vertical monopole radiator will
reduce the radiated field at ALL elevation angles including those producing
a useful skywave-- not just in the horizontal plane producing the ground
wave.

RF http://rfry.org

"Quarter wave ground mounted radials are a waste of wire."
 

"Nate Bargmann" wrote in message
.. .
On Sun, 23 Sep 2007 12:59:49 -0500, Richard Fry wrote:

"Rick wrote

... What say you all?

Read "Ground Systems as a Factor in Antenna Efficiency" by Brown, Lewis
& Epstein of RCA Labs, published in the June, 1937 issue of The
Proceedings of the I.R.E.

It proves otherwise.

Honest question, does it matter whether the objective is a strong ground
wave as in AM broadcast or skywave as in amateur operation?

I am installing a Hustler 4BTV this fall and have put down (so far) 16
radials that range from about 18 to 35 feet in length due to my servere
space restrictions. I may add 16 more later this fall as an experiment.

73, de Nate

It would be interesting to follow the change in VSWR as you add individual
radials. Some years ago, there was a discussion of adding radials until the
VSWR stopped increasing. This was based on an expected feedpoint resistance
of 36 ohms, and an assumption that the ground losses were 15 ohms or less.
So at the worst case, the VSWR was near 1:1. The best case, with a ground
loss approaching 0 ohms, would have a VSWR of 50/36= 1.39:1.

I want to attribute the original discussion to W2DU, but I stop short of
that, in case I don't remember correctly.

"Quarter wave ground mounted radials are a waste of wire."
 

On Wed, 26 Sep 2007 16:56:27 GMT, "Wayne"
wrote:

It would be interesting to follow the change in VSWR as you add individual
radials. Some years ago, there was a discussion of adding radials until the
VSWR stopped increasing. This was based on an expected feedpoint resistance
of 36 ohms, and an assumption that the ground losses were 15 ohms or less.
So at the worst case, the VSWR was near 1:1. The best case, with a ground
loss approaching 0 ohms, would have a VSWR of 50/36= 1.39:1.

Hi Wayne,

This strategy may also have you stop adding radials too early when
your antenna presented 36 Ohms looking into a ground loss of 33 Ohms
(same SWR of 1.39).

73's
Richard Clark, KB7QHC

"Quarter wave ground mounted radials are a waste of wire."
 

"Richard Clark" wrote in message
The best case, with a ground loss approaching 0 ohms, would
have a VSWR of 50/36= 1.39:1.
___________

A set of 120 buried radials each at least 1/4-wave long (free space value)
will produce an r-f ground resistance of around 2 ohms, maybe less in soil
with very good conductivity.

But in any case the impedance existing between the base of a series-fed
vertical monopole and the common point of the buried radials will depend on
the electrical height of the monopole which includes the ratio of its height
to its width, as well as the r-f resistance in the ground system itself.

Broadcast stations will install the tower and radials, measure the Z from
the tower base to the radials, and transform whatever that value is to 50
+j0 ohms using a network at the base of the tower.

Fewer radials will mean that the ground loss will increase, and system
radiation efficiency will decrease (even if the VSWR is 1:1)

RF

"Quarter wave ground mounted radials are a waste of wire."
 

"Richard Clark" wrote in message
...
On Wed, 26 Sep 2007 16:56:27 GMT, "Wayne"
wrote:

It would be interesting to follow the change in VSWR as you add individual
radials. Some years ago, there was a discussion of adding radials until
the
VSWR stopped increasing. This was based on an expected feedpoint
resistance
of 36 ohms, and an assumption that the ground losses were 15 ohms or less.
So at the worst case, the VSWR was near 1:1. The best case, with a ground
loss approaching 0 ohms, would have a VSWR of 50/36= 1.39:1.

Hi Wayne,

This strategy may also have you stop adding radials too early when
your antenna presented 36 Ohms looking into a ground loss of 33 Ohms
(same SWR of 1.39).

73's
Richard Clark, KB7QHC

Right. I guess the better way to state it is to stop adding radials when
the r component stops dropping. I've always wanted to try that experiment,
but real estate considerations have prevented it.

"Quarter wave ground mounted radials are a waste of wire."
 

On Sun, 23 Sep 2007 12:46:30 -0400, "Rick (W-A-one-R-K-T)"
wrote:


I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

What say you all?

Read this and see if you really want to know more.

http://www.bencher.com/pdfs/00361ZZV.pdf

A challenge to all you experts out the
Can you find anything you disagree with in this document?

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

"Quarter wave ground mounted radials are a waste of wire."
 

"John Ferrell" wrote in message
...
On Sun, 23 Sep 2007 12:46:30 -0400, "Rick (W-A-one-R-K-T)"
wrote:


I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

What say you all?

Read this and see if you really want to know more.

http://www.bencher.com/pdfs/00361ZZV.pdf

A challenge to all you experts out the
Can you find anything you disagree with in this document?

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

An excellent reference John. All nicely explained and with pictures. :-)
Mike G0ULI

"Quarter wave ground mounted radials are a waste of wire."
 

On Sep 26, 9:56 am, "Wayne" wrote:
"Nate Bargmann" wrote in message

.. .

On Sun, 23 Sep 2007 12:59:49 -0500, Richard Fry wrote:

"Rick wrote

... What say you all?

Read "Ground Systems as a Factor in Antenna Efficiency" by Brown, Lewis
& Epstein of RCA Labs, published in the June, 1937 issue of The
Proceedings of the I.R.E.

It proves otherwise.

Honest question, does it matter whether the objective is a strong ground
wave as in AM broadcast or skywave as in amateur operation?

I am installing a Hustler 4BTV this fall and have put down (so far) 16
radials that range from about 18 to 35 feet in length due to my servere
space restrictions. I may add 16 more later this fall as an experiment.

73, de Nate

It would be interesting to follow the change in VSWR as you add individual
radials. Some years ago, there was a discussion of adding radials until the
VSWR stopped increasing. This was based on an expected feedpoint resistance
of 36 ohms, and an assumption that the ground losses were 15 ohms or less.
So at the worst case, the VSWR was near 1:1. The best case, with a ground
loss approaching 0 ohms, would have a VSWR of 50/36= 1.39:1.

I want to attribute the original discussion to W2DU, but I stop short of
that, in case I don't remember correctly.

I think it would be a lot MORE interesting to follow the change in
_impedance_ as you add wires. I can see a lot that can go wrong with
"adding radials till the SWR stops increasing." I don't think that
the case of 33 ohms ground resistance is one to seriously consider*,
but if you're operating over really poor ground and/or your "quarter
wave" antenna isn't really a quarter electrical wave, you may see
significant reactive component that you'll never resolve with an SWR
meter. You'll likely get very confused by it instead.

*What's the "ground resistance" with as few as two radials, even if
there's no earth ground nearby? What if there are no radials but the
ground is really awful? Some "what-ifs" with EZNEC or the like can
give you an appreciation for what happens...

Cheers,
Tom

"Quarter wave ground mounted radials are a waste of wire."
 

An excellent reference John. All nicely explained and with pictures. :-)
Mike G0ULI
I am continually amazed at the amount and quality of information on
the Internet. I am also dismayed how hard it is to separate out the
good from the worthless.

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

"Quarter wave ground mounted radials are a waste of wire."
 

On Sep 27, 7:45 am, John Ferrell wrote:
On Sun, 23 Sep 2007 12:46:30 -0400, "Rick (W-A-one-R-K-T)"

wrote:

I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

What say you all?

Read this and see if you really want to know more.

http://www.bencher.com/pdfs/00361ZZV.pdf

A challenge to all you experts out the
Can you find anything you disagree with in this document?

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

That seems a very practical ap note. But since you issued the
challenge, I'll say I disagree with the wording of an early sentence,
where it says that ground return currents are "greatly attenuated" if
they come through lossy earth. Clearly, the current is not
attenuated; the current is what it is. However, the current through
lossy ground causes power dissipation (and loss of radiated power) in
the ground.

I think the meaning is clear, but the wording would not pass muster
with a good technical editor.

Cheers,
Tom

"Quarter wave ground mounted radials are a waste of wire."
 

On Fri, 28 Sep 2007 20:21:23 -0700, K7ITM wrote:

On Sep 27, 7:45 am, John Ferrell wrote:
On Sun, 23 Sep 2007 12:46:30 -0400, "Rick (W-A-one-R-K-T)"

wrote:

I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and a hold over
from the olden days. Check the antenna handbook, the new philosophy is
more and shorter. The thing is that the bulk of the energy from the
vertical antenna is near the base of the antenna and this is what you are
trying to capture. A quarter wave radial sounds logical but the planet
will detune it so a quarter wave means nothing to the current."

That seems a very practical ap note. But since you issued the
challenge, I'll say I disagree with the wording of an early sentence,
where it says that ground return currents are "greatly attenuated" if
they come through lossy earth. Clearly, the current is not
attenuated; the current is what it is. However, the current through
lossy ground causes power dissipation (and loss of radiated power) in
the ground.

I think the meaning is clear, but the wording would not pass muster
with a good technical editor.

Cheers,
Tom
Good catch. It could have been more precisely stated.
In defense of the the point, Dictionary.com offers this definition of
"attenuated"- to weaken or reduce in force, intensity, effect,
quantity, or value.

OTH, lossy earth is a limiting factor to the current component of the
equation.

I think it unlikely to be misinterpretd so I would be inclined to
leave it alone. Of course, I am not a Technical Editor.

John Ferrell W8CCW
"Life is easier if you learn to
plow around the stumps"

"Quarter wave ground mounted radials are a waste of wire."
 

"K7ITM" wrote
... I'll say I disagree with the wording of an early sentence,
where it says that ground return currents are "greatly attenuated"
of they come through lossy earth. Clearly, the current is not
attenuated; the current is what it is. However, the current through
lossy ground causes power dissipation (and loss of radiated
power) in the ground.
___________

But without a low-loss r-f ground for a monopole such as provided by a good
buried radial system, those returning r-f currents ARE greatly attenuated
before they can enter into the ground terminal of the antenna system.

That ground resistance is in series with the radiation resistance of the
monopole, and so will reduce the current that will flow on the monopole --
hence the field it will radiate.

RF

"Quarter wave ground mounted radials are a waste of wire."
 

Rick (W-A-one-R-K-T) wrote
I just read the following on one of the mailing lists I subscribe to:

"Quarter wave ground mounted radials are a waste of wire and
a hold over from the olden days. Check the antenna handbook,
the new philosophy is more and shorter...."
____________

Below is a link to a calculator on the FCC website giving some
insight into this. It restricts inputs to values allowed for AM broadcast
stations, but still might be of some value to amateurs.

For one example, it shows a 1/4-wave monopole using 120 x
1/4-wave buried radials as generating a groundwave field of
about 306 mV/m at 1 km for 1 kW of applied power.

If the number of radials is reduced to 90, and their length is reduced
to 0.153 wavelength, the groundwave field is reduced to 267 mV/m.

The difference in radiated power then is (267/306)^2, or about
24%, which value is dissipated by heating the earth.

Whether or not that reduction is important to amateurs is a judgment call.
But an antenna system producing 267 mV/m for these conditions would be
unusable by a "regional" AM broadcast station -- which per their station
license must produce a groundwave rms field of at least 282 mV/m at 1 km
for 1 kW of applied power.

http://www.fcc.gov/mb/audio/bickel/figure8.html

RF

"Quarter wave ground mounted radials are a waste of wire."
 

K7ITM wrote:
I'll say I disagree with the wording of an early sentence,
where it says that ground return currents are "greatly attenuated" if
they come through lossy earth. Clearly, the current is not
attenuated; the current is what it is.

There is some confusion between DC circuits and
distributed RF networks. In a DC circuit, the
current is the same throughout the circuit. In
a distributed RF network, the current is usually
*NOT* the same throughout the network. One can
put one amp of current into a buried radial and
measure zero amps from some point outward.

In particular, when dealing with RF EM waves, the
H-field to which the current is proportional in
a transmission line is attenuated by the same
attenuation factor as is the E-field to which
the voltage is proportional. Please reference
the transmission line equations to verify that
fact.

Such is easy to see. If one has a flat Z0=50 ohm
transmission line with 100 watts in and 50 watts
out, there is 1.414 amps in and 1.0 amp out because
the ratio of voltage to current is fixed at 50 ohms.
The traveling-wave current in an EM wave in a
transmission line (or in a radial in lossy earth)
is attenuated exactly as much as the voltage.

And don't feel too ignorant about that fact of physics.
Some of the gurus on this newsgroup make a similiar
mistake about RF EM wave current through a loading coil.
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

Richard Fry wrote:
... those returning r-f currents ARE greatly
attenuated before they can enter into the ground terminal of the antenna
system.

Richard, too many people, including some of the gurus,
are thinking DC circuits. The only difference between
the voltage equation and the current equation is a
division by Z0, i.e. the current is attenuated exactly
by the same factor as the voltage.
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

Richard Fry wrote:

Below is a link to a calculator on the FCC website giving some
insight into this. It restricts inputs to values allowed for AM broadcast
stations, but still might be of some value to amateurs.

For one example, it shows a 1/4-wave monopole using 120 x
1/4-wave buried radials as generating a groundwave field of
about 306 mV/m at 1 km for 1 kW of applied power.

If the number of radials is reduced to 90, and their length is reduced
to 0.153 wavelength, the groundwave field is reduced to 267 mV/m.

The difference in radiated power then is (267/306)^2, or about
24%, which value is dissipated by heating the earth.

Whether or not that reduction is important to amateurs is a judgment
call. But an antenna system producing 267 mV/m for these conditions
would be unusable by a "regional" AM broadcast station -- which per
their station license must produce a groundwave rms field of at least
282 mV/m at 1 km for 1 kW of applied power.

http://www.fcc.gov/mb/audio/bickel/figure8.html

RF

This is a good example of why we shouldn't assume that what's suitable
or optimum for AM broadcasting or some other service is necessarily the
best solution for amateur applications. A reduction in radiated power of
24% is just about 1 dB. While this amount of attenuation makes the
system unsuitable for AM broadcasting, it would be difficult to even
detect that amount of difference except just perhaps in the most
demanding amateur communication -- right at the noise level -- and it
would go completely unnoticed in the vast majority of cases.

Roy Lewallen, W7EL

"Quarter wave ground mounted radials are a waste of wire."
 

Cecil Moore wrote:

There is some confusion between DC circuits and
distributed RF networks.

No comment.

In a DC circuit, the
current is the same throughout the circuit.

That's true only for a simple series circuit. And it's true for RF
as well.

In
a distributed RF network, the current is usually
*NOT* the same throughout the network.

The same is true for a DC network.

One can
put one amp of current into a buried radial and
measure zero amps from some point outward.

In particular, when dealing with RF EM waves, the
H-field to which the current is proportional in
a transmission line is attenuated by the same
attenuation factor as is the E-field to which
the voltage is proportional. Please reference
the transmission line equations to verify that
fact.

Such is easy to see. If one has a flat Z0=50 ohm
transmission line with 100 watts in and 50 watts
out, there is 1.414 amps in and 1.0 amp out because
the ratio of voltage to current is fixed at 50 ohms.
The traveling-wave current in an EM wave in a
transmission line (or in a radial in lossy earth)
is attenuated exactly as much as the voltage.

Note: according to Ohms law, current scales directly with voltage and
inversely with resistance.

ac6xg

"Quarter wave ground mounted radials are a waste of wire."
 

Jim Kelley wrote:
In a DC circuit, the
current is the same throughout the circuit.

That's true only for a simple series circuit. And it's true for RF as
well.

A foot of wire with reflections at one GHz has
the same current throughout the circuit?
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

On Oct 1, 9:09 pm, Cecil Moore wrote:
Jim Kelley wrote:
In a DC circuit, the
current is the same throughout the circuit.

That's true only for a simple series circuit. And it's true for RF as
well.

A foot of wire with reflections at one GHz has
the same current throughout the circuit?
--
73, Cecil http://www.w5dxp.com

A simple series circuit can be expected to behave as a simple series
circuit. Other circuits can be expected to behave differently. Which
do you think applies?

ac6xg

"Quarter wave ground mounted radials are a waste of wire."
 

Jim Kelley wrote:
Cecil Moore wrote:
A foot of wire with reflections at one GHz has
the same current throughout the circuit?

A simple series circuit can be expected to behave as a simple series
circuit. Other circuits can be expected to behave differently. Which
do you think applies?

An *ordinary prudent man* would think that one foot
of wire is a "simple series circuit" and it is in a
DC circuit. If as you say, the current in an RF circuit
is the same throughout, why does the current vary
every inch in a circuit with reflections?
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

Cecil Moore wrote:
Jim Kelley wrote:

Cecil Moore wrote:

A foot of wire with reflections at one GHz has
the same current throughout the circuit?


A simple series circuit can be expected to behave as a simple series
circuit. Other circuits can be expected to behave differently. Which
do you think applies?


An *ordinary prudent man* would think that one foot
of wire is a "simple series circuit" and it is in a
DC circuit.

Most ordinary prudent men that I know wouldn't characterize a one foot
length of wire as a series circuit.

ac6xg

"Quarter wave ground mounted radials are a waste of wire."
 

Jim Kelley wrote:

Most ordinary prudent men that I know wouldn't characterize a one foot
length of wire as a series circuit.


Come on now guys, let's get series!

- 73 de Mike KB3EIA -

"Quarter wave ground mounted radials are a waste of wire."
 

On Oct 2, 10:33 am, Jim Kelley wrote:
Cecil Moore wrote:
Jim Kelley wrote:

Cecil Moore wrote:

A foot of wire with reflections at one GHz has
the same current throughout the circuit?

A simple series circuit can be expected to behave as a simple series
circuit. Other circuits can be expected to behave differently. Which
do you think applies?

An *ordinary prudent man* would think that one foot
of wire is a "simple series circuit" and it is in a
DC circuit.

Most ordinary prudent men that I know wouldn't characterize a one foot
length of wire as a series circuit.

ac6xg

The fact that it's described as having a physical dimension suggests
that the physical extent matters. I don't know what an "ordinary
prudent man" is, but I suppose most people I stopped on the street
wouldn't have a clue what I was talking about and their eyes would
kind of glaze over with the mention of "wire" and "circuit."

Cheers,
Tom

(presently playing with circuits below 100MHz where 1mm can make a
huge difference in performance...who finds folk who say we don't
understand such things as distributed circuits deeply offensive,
especially when they make it abundantly clear they don't understand
such circuits themselves...)

"Quarter wave ground mounted radials are a waste of wire."
 

Jim Kelley wrote:

Cecil Moore wrote:
An *ordinary prudent man* would think that one foot
of wire is a "simple series circuit" and it is in a
DC circuit.

Most ordinary prudent men that I know wouldn't characterize a one foot
length of wire as a series circuit.

More silly word games - when it is in a DC circuit
the current is constant. When it exists in a simple
series GHz circuit with reflections, the current
is not constant.
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

"Cecil Moore" wrote in message
...
Jim Kelley wrote:

Cecil Moore wrote:
An *ordinary prudent man* would think that one foot
of wire is a "simple series circuit" and it is in a
DC circuit.

Most ordinary prudent men that I know wouldn't characterize a one foot
length of wire as a series circuit.

More silly word games - when it is in a DC circuit
the current is constant. When it exists in a simple
series GHz circuit with reflections, the current
is not constant.
--
73, Cecil http://www.w5dxp.com

you don't even need reflections. a properly terminated piece of wire has a
different current at every point along the wire.

"Quarter wave ground mounted radials are a waste of wire."
 

Dave wrote:
"Cecil Moore" wrote in message
...

Jim Kelley wrote:

Cecil Moore wrote:

An *ordinary prudent man* would think that one foot
of wire is a "simple series circuit" and it is in a
DC circuit.

Most ordinary prudent men that I know wouldn't characterize a one foot
length of wire as a series circuit.

More silly word games - when it is in a DC circuit
the current is constant. When it exists in a simple
series GHz circuit with reflections, the current
is not constant.
--
73, Cecil http://www.w5dxp.com


you don't even need reflections. a properly terminated piece of wire has a
different current at every point along the wire.

At any given instant. :-)

ac6xg

"Quarter wave ground mounted radials are a waste of wire."
 

Dave wrote:
you don't even need reflections. a properly terminated piece of wire has a
different current at every point along the wire.

That's true but the attenuation factor in one foot
of wire might be hard to measure. Introduce reflections
and even a lossless wire will vary the current from
max to min every few inches at GHz frequencies.
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

"Cecil Moore" wrote in message
...
Dave wrote:
you don't even need reflections. a properly terminated piece of wire has
a different current at every point along the wire.

That's true but the attenuation factor in one foot
of wire might be hard to measure. Introduce reflections
and even a lossless wire will vary the current from
max to min every few inches at GHz frequencies.
--
73, Cecil http://www.w5dxp.com

you don't need any loss either. a properly matched lossless line will have
different current at each point along the line.

"Quarter wave ground mounted radials are a waste of wire."
 

Dave wrote:
you don't need any loss either. a properly matched lossless line will have
different current at each point along the line.

Different RMS current?
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

"Jim Kelley" wrote in message
...


Dave wrote:
"Cecil Moore" wrote in message
...

Jim Kelley wrote:

Cecil Moore wrote:

An *ordinary prudent man* would think that one foot
of wire is a "simple series circuit" and it is in a
DC circuit.

Most ordinary prudent men that I know wouldn't characterize a one foot
length of wire as a series circuit.

More silly word games - when it is in a DC circuit
the current is constant. When it exists in a simple
series GHz circuit with reflections, the current
is not constant.
--
73, Cecil http://www.w5dxp.com


you don't even need reflections. a properly terminated piece of wire has
a different current at every point along the wire.

At any given instant. :-)

ac6xg

TADA! And Jim gets the cigar!

Cecil, you take too narrow a view. at any given instant in time if you
measure the current along a properly matched wire you will measure a
different current and voltage all along the wire (repeating every wavelength
minus losses of course). nothing was stated that required rms, other
average, peak, or phasor representation.

"Quarter wave ground mounted radials are a waste of wire."
 

Dave wrote:
nothing was stated that required rms, other
average, peak, or phasor representation.

Nothing was stated that required the signal
source to be turned on either.
--
73, Cecil http://www.w5dxp.com

"Quarter wave ground mounted radials are a waste of wire."
 

Dave wrote:
"You don`t even need reflections. A properly terminated piece of wire
has a different current at every point along the wire."

Instantaneous values, of course. But, proper termination means no
reflection. The only source of variation along a line other than
attenuation is reflection. In a uniform line, attenuation causes a
steady decline of energy as energy travels. With a lossless line,
properly terminated, variation of rnergy along a line is only the phase
produced instantaneois values along the line. These are resolved during
the period of a cycle by the root mean square calculation.

Best regards, Richard Harrison, KB5WZI