Richard Fry wrote:
If in both cases the matching network has a 2 ohm loss, there is a 10
ohm loss in the r-f ground connection, ...

Thanks, I should have said the problem is getting the
RF energy into the radiation resistance.
--
73, Cecil http://www.qsl.net/w5dxp

Thanks to all,

for your comments and opinions.
I expected this type of arguments!

Let me comment them:
N3OX, Dan, wrote his confession in antennas...
The fundamentel part :"We believe in the fundemental difficulty of
delivering power efficiently to physically small radiating structures,
and we understand the limitations it places on such structures as
compared to their full-size counterparts."
The difficulty is here, and most antennas of traditional design are suffering
under this, and therefore are inefficient, if the relation l/lamdba is small.
That's different in my design:
The Varylink is part of the antenna and permits to feed the available
input power with over 90% efficiency into the radiation resistance Rr of
the antenna. Furthermore, the relation Rr / Rloss is very high, which
ensures that the power is radiated, and not burned.

Wim, PA3DJS, is addressing a very similar problem.
He calculates an overall efficiency of 5% (-13db) under his assumptions.
He is also basing his calculation on data available from traditional
constructions. Im my design X/r is between 28 and 50, depending
upon frequency and version, and at the same time the total series
loss resistance is about 10 times smaller than the radiation resistance.
These characterists ensure, that the efficiency (radiated power/accepted power)
is in the order of 90 percent.

Cecil, W5DXP, is referring to EZNEC, calculating that the small antenna might
achieve practically the same radiation as 1/4 lambda monopole.
His problem again is, how to get the power into the radiation resistance of
the antenna. This is done as said above.

RF, Richard Fry, is addressing the losses in the matching, and most important,
in the ground loss.
The efficient matching is answered above.
The ground loss is very important for efficient radiation of the energy into
space and not into the ground!
This ground loss is not addressed in the IEEE formula for calculation of antenna
efficiency, as it says: efficency = radiated-power/antenna-accepted-power.
This does not take care of the fact, that in most real antennas, a large amount
of the radiated power is lost in the ground as induced ground currents!

To minimise these losses I am using a special grounding concept, based on
a differential, floating feeding system, ensuring that ground losses are minimal, and that
the radiated RF energy reaches the space towards the ionosphere.
All this ensures the high efficiency of the small antenna, so far not
reached by other designs.

Felix Meyer, HB9ABX

Felix,

I call Bull****. Show us REAL data on the efficiency of this antenna.
Show us field strength vs. a full size 1/4 wave vertical with a good
ground system. If you've invented something new and innovative,
awesome, but the world will never know about it. Why? Because you
won't do real tests.

You want people to buy your plans. You make outrageous claims of
efficiency with no data to back it up other than signal reports from
closeby EU stations on 160m. As far as I'm concerned, at best, you're
a optimist blinded by excitement who's built a pretty good low band
mobile antenna and doesn't want to let himself down by measuring
anything. At worst, you're an outright scammer.

Actually, you know what, how much do you want for the plan again?
Maybe we can take up a collection so we can build one and prove that
you're wrong. But you know , I bet if we build it and it doesn't work
as advertised, you'll make some claim about construction tolerances or
sensitivity to nearby objects, or some such and still claim that YOUR
antenna is 90% efficient. Such is the way of a good pseudoscientist.

Dan

Dan, N3OX, please no flames. That is not the correct style here ...

You are criticising by error, or by ignorance.
I did the measuring of the efficiency by feeding the RoomCap antenna with 1 KW HF,
havinga VSWR below 1,1 and the result: Less than 70 W heat is produced by the
antenna, and, as energy can not be destroyed, 930 W was radiated by the antenna.

The definition of efficiency by the IEEE is:
"The radiation efficiency of an antenna is the ratio of the total power radiated by
the antenna to the net power accepted by the antenna at its terminals."

You can measure these data your own, using your instruments in your laboratory.
The construction plan is available. You get it a a very moderate cost, for 30 Euros,
as contribuiton to the development costs.
This is less than you pay here in a restaurant for dining with a drink.
And you call that "business". Please keep realistic and study before
you accuse me of what you did.

Regarding the tests on 160m you commented:
I was testing between 22h and 24h local time, during the last weeks.
At this time no oversea stations were reachable due to the present conditions.
Even the biggest european stations were calling CQ DX, using Kilowatts, without
any reply from DX.
When calling on 1933 Khz, a pile-up of UK stations appeared. They all wanted to
contact me - and gave very good reports. Ask John, G3WWM and Eric, G3IMX
who are very familiar with the 160m band with decades of experience.

73s

Felix HB9ABX

On Wed, 13 Sep 2006 11:57:28 +0000, Felix
wrote:

Dan, N3OX, please no flames. That is not the correct style here ...

You are criticising by error, or by ignorance.

Hi Felix,

Given your statements that follow, it appears that Dan IS criticizing
about error and about ignorance:

I did the measuring of the efficiency by feeding the RoomCap antenna
with 1 KW HF,
havinga VSWR below 1,1

Your claims are based on very thin technical knowledge - and your lack
of experience shows. VSWR is not an indication of efficiency - far
from it. I seriously doubt you know how to measure the V of VSWR.
Your meter measures power, not V. Your understanding of the SWR
versus efficiency relationship also reveals a lack of basic
understanding. For small antennas, low SWR can be solid proof of high
inefficiency. The simple fact of the matter is that no small antenna
presents a load that is remotely close to any standard transmitter's
output Z, nor any commercial transmission line.

I fully expect you will attempt to claim matching solves this. When
you do attempt that, we will clear up your lack of experience there
too.

and the result: Less than 70 W heat is produced
by the
antenna, and, as energy can not be destroyed, 930 W was radiated by the
antenna.

In fact, you do not prove you measured 10W heat, nor 20W heat, nor 40W
heat, nor "less than 70W heat." You cannot even prove you radiated
930W watts. There are methods to "prove" these claims, and you don't
show any knowledge of those basic principles. Relying on one
definition (poorly extracted from a text) is not sufficient. It may
qualify for sales, but this is not a sales group and you are not going
to find customers here with your poor quality of discussion.

This leaves us with one question: "What do you expect to achieve
here?"

73's
Richard Clark, KB7QHC

In article , Richard Clark
wrote:

This leaves us with one question: "What do you expect to achieve
here?"

73's
Richard Clark, KB7QHC

Hello, and if you're a good enough salesman and have at least one
university professor to explanation your "interpretation" of
electromagnetic theory, you could rename the antenna "Son of CFA" ;-) At
some point, however, a prospective customer is going to require some
verifiable test data.

All kidding aside, the challenge is the use of technique(s) that allows
for the direct or indirect measurement of radiation resistance and loss
(structure including any earth loss in the vicinity of the feedpoint)
resistance over the operating frequency range. A measurement of the real
(resistive) part of the antenna feedpoint impedance can only provide the
sum of both types of resistance. We know how much power is being
dissipated (heat + radiated) but that's all we can know from this one
measurement.

There is also the shape of the radiation pattern...but that is another
matter. Sincerely, and 73s from N4GGO,

John Wood (Code 5550) e-mail:
Naval Research Laboratory
4555 Overlook Avenue, SW
Washington, DC 20375-5337

Felix,

I apologize for the strong language.

I would believe that you've designed and built a quite good mobile
antenna that impresses veteran topband operators. However, it's not
turning 93% of the power you're feeding it into radiation. I barely
believe that it might be taking 7% of the power you're feeding it and
turning it into heat in the antenna, but what about the ground return
losses in the earth? These are, of course, proportional to the square
of the current flowing in ground system. You seemed to suggest that
your method of matching to the low radiation resistance is practically
lossless. Even if this were to be true, and there were no loss in the
matching network or the antenna conductor, you still must have a
connection to earth. If this connection is not perfectly conducting,
pushing all that current into it will result in high losses. For a
ground system with 1 ohm of ground loss, and an antenna radiation
resistance of 0.2 ohms, assuming a lossless matching network and
radiator, I get an efficiency of 12% over PERFECT earth. Taking the
ground reflection losses into account over average ground, it's about
5%. This is assuming PERFECT matching network and a very good (maybe
impossibly good?) grounding system. The ground return current has to
flow somewhere, the matching network I'm assuming is a black box. It
doesn't matter what it is or how novel it is, the ground return current
has to flow in your grounding system, and with an antenna as short as
yours, that's a LOT of current. You do realize that if you were
completely losslessly feeding 1kW into 0.2 ohms, the antenna current
would be 70.7A, right?

You won't notice a kilowatt's worth of power dissipation in your car
and the earth around it.

Felix, are you willing to do an experiment? Feed your RoomCap antenna
against another one as a dipole, adjust the matching network for a good
match, and feed 1kW into it and measure the heat produced in the
matching network and antenna, if it survives long enough to do so.

And another thing, Felix... even a full size, perfectly conducting 1/4
wavelength monopole with a practically lossless place for the ground
return currents to flow doesn't radiate more than about 30% of the
power applied to it anyway over average earth. The ground reflection
losses in the Fresnel zone dissipate much of the power. This is better
over better earth of course, but I doubt your antenna has some sort of
control over the soil conductivity and permittivity for tens of
wavelengths in every direction. You may wish to revise your claims of
93% efficiency down to 93% efficiency relative to a full size ground
mounted 1/4 wavelength monopole; it would be a more convincing untruth.

One further comment: I have a hard time believing that these are all
innocent mistakes.. It reflects badly on your character to make vague,
inaccurate statements about a miraculous antenna and then tell people
they need to dish out 30 Euros just to be able to try it. My apologies
for thinking you're a big scammer if you are merely a victim of your
own optimism.... I could see the argument that only 70W are being
dissipated in the antenna as convincing even the innocent experimenter
that he was on to something big! However, now you know the truth. If
you revise your claims with an eye to the reality of feeding a small
antenna against the earth, then I won't be so upset with you.

It is counter to the ham spirit to mislead people in this way, if
that's what you're doing, and only you know that. We are all trying to
learn RF engineering in our spare time, and it's important that the new
hams out there take their 38 bucks and apply it to their inverted L
project for 160m, or a copy of ON4UN's low band DXing book instead of
handing them over to you for the plans to one disappointing antenna.


73,
Dan

d an antenna radiation
resistance of 0.2 ohms, assuming a lossless matching network and
radiator, I get an efficiency of 12% over PERFECT earth. Taking the
ground reflection losses into account over average ground, it's about
5%. This is assuming PERFECT matching network and a very good (maybe

new hams out there take their 38 bucks and apply it to their inverted L
project for 160m, or a copy of ON4UN's low band DXing book

Great advice Dan. That book, in my opinion, is the finest book ever
written concerning practical information for the HF operator. And I
have read them all.
You know, one thing that impressed me (and there were many) in that
book is where he admitted that previous versions were wrong in telling
us there was benefit to sloping the end of a Beverage antenna down to
the feedpoint. Simply running it vertically down is the same. To
readers of this newsgroup, if you have only read previous editions,
you should get the new one. It is completely rewritten.

Rick K2XT

Rick wrote:
To
readers of this newsgroup, if you have only read previous editions,
you should get the new one. It is completely rewritten.

In a nutshell, what does he say about the delay/phase-shift
through a loading coil in the latest edition?
--
73, Cecil http://www.w5dxp.com

On Fri, 15 Sep 2006 15:55:03 GMT, (Rick) wrote:

d an antenna radiation
resistance of 0.2 ohms, assuming a lossless matching network and
radiator, I get an efficiency of 12% over PERFECT earth. Taking the
ground reflection losses into account over average ground, it's about
5%. This is assuming PERFECT matching network and a very good (maybe

new hams out there take their 38 bucks and apply it to their inverted L
project for 160m, or a copy of ON4UN's low band DXing book

Great advice Dan. That book, in my opinion, is the finest book ever
written concerning practical information for the HF operator. And I
have read them all.
You know, one thing that impressed me (and there were many) in that
book is where he admitted that previous versions were wrong in telling
us there was benefit to sloping the end of a Beverage antenna down to
the feedpoint. Simply running it vertically down is the same. To
readers of this newsgroup, if you have only read previous editions,
you should get the new one. It is completely rewritten.

Rick K2XT


What is the latest edition?
I see 2005 4th ed.
Thanks
Dave Foreman