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