Hallo Bryan, Alberto and All,
let me tell my own experience with an E/H-antenna.
This year on the FRIEDRICHSHAFEN exhibition WIMO offered such antennas. The
advertising text was "like dipole" or "similar to dipole". Whatever that
means.
Coming back I built my own antenna. A rainfall-pipe 16cms Diameter, 70cms
long. The coil on it 23 turns of insulated wire, close together. Another
coil of 2 turns for coupling. At both ends of the pipe a stripe of copper,
1m long, 15cms wide. The stripes are connected to the ends of the coil. This
antenna was put 6meter over ground in free surroundings and fed by RG58. I
could compare it with a dipole by a switch-"click". Frequency is 3,7MHz.
L=107uH (measured), C=17,3pF (calculated).
Results, receiving: The signals are in general 2 to 3 S-stages lower than
from the dipole. That`s normally not so bad, because the noise is also
lower. Signals, that are already very weak with the dipole are not
detectable with the E/H-antenna.
Transmitting: The same, reports are clearly lower than with the dipole. It
is not difficult to make QSO` in CW, but more in SSB.
(Our QRP-friends show every day, how to make QSO`s with 1 to 5w on a dipole,
it`comparable)
I think, this antenna is the opposite of the loop. And its gain can be
compared with the gain of a loop of similar size.
AMA (produces loops) published a diagram. It shows, that the 0.8m-loop on
3,7MHZ has a gain of -18db. Let us assume, that this is realistic. Then
theory matches with the experience.
Although we all would like to have the very small antenna with 99%
efficiency - the wonder-antenna is not yet at the horizon.
Sorry, the laws of nature are still valid.
73 Walter DJ2LF
-----Ursprüngliche Nachricht-----
Von: Alberto di Bene <[email protected]>
An: [email protected] <[email protected]>
Datum: Freitag, 23. Juli 2004 16:50
Betreff: LF: Re: Loops v Verticals
captbrian wrote:
I disagree. To the best of my knowledge the E-H antennas never
demonstrated
anything more than one would expect from what they were.; ie short
antennas with inductive centre loading and capacitative end loading ..
They fitted normal theory quite well as did the ephemeral "fractal"
antenna.
Bryan G3GVB
Bryan,
we do completely agree. But the point is that the EH-antenna priests
have a different point of view.
They claim that their toy is a breakthrough in the electromagnetic
theories. According to them the
classical theory (Maxwell's) cannot explain the PVS (Poynting Vector
Synthesis), which, still according
to them, is the reason why the EH-antenna works. So they claim for a
revision of the classical theory.
Now this claim is founded on the experimental evidence that, somehow,
the EH-antenna seems to radiate.
Hence, from the fact that experiment apparently is not in complete
accord with theory, they want to change
the theory. What they fail to understand (in good faith or for more
venal reasons...) is that the error is in
the experiment, as what radiates in their tests is the feeder line, as
shown by other tests performed by
open-minded persons, not adepts of the EH religion.
73 Alberto I2PHD
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