RadioBanter - EH Antenna Revisited

RadioBanter (https://www.radiobanter.com/)

- Antenna (https://www.radiobanter.com/antenna/)

- - EH Antenna Revisited (https://www.radiobanter.com/antenna/1052-eh-antenna-revisited.html)

Richard:

"One can observe a gain relative
between two antennas and this would require significant differences in
the two patterns. "

I believe this is in line with what Ted says...the EH purportedly has
vertical adjustable pattern depending on the length to diameter ratio of the
cylinders.

"However, the data from the FCC methods of testing
prove there is no difference. "

Well, that's the way I interpreted the data too. However, I don't believe
this was a 3 dimensional measurement, was it?

Joe
W3JDR

Walter Maxwell wrote:
"To anyone who believes the W5QJR EH conceptis valid."

OK. I read the first page: "Welcome to the Wonderful World of EH
Antennas". It said nothing of why I should be interested. Why convert an
existing broadcast antenna to EH?

FCC has a publication, "Rules of Good Engineering Practice for Standard
Broadcast Stations" which includes Mv/m at 1 mile on a radial over
perfect earth from a vertical antenna of various heights. It shows about
195 mV/m for a 1/4-wave grounded vertical.

This can be adjusted for any power or diistance from the sender:

E = Eo sq rt P/d

Eo = 195 mV/m for the 1/4-wave antenna at 1 mile

P = the actual radiated power

d = distance from antenna in miles

The mV/m at a mile assumes a perfect ground and a perfect antenna ground
system. FCC says 120 radials equally spaced and 1/2-wavelength long are
its standard. Efficiency typically exceeds 95%.

If the vertical radiator is higher (longer) than !/8-wavelength, the 150
mV/m at 1 mile, required minimum efficiency, can still be met with 120
radials on the earth that are only 1/4-wavelength long. The reduction in
efficiency is small.

Nobody has perfect ground unless he is at sea. For imperfect ground, the
FCC publishes "Ground Wave Propagation Curves" for various soil
conductivities.

In the FCC millivolt per meter numbers for vertical antennas of various
heights, the field strength only increases 5% in going from very short
to a full 1/4-wave height. This requires the near perfect ground. A
3/8-wave radiator only has a 15% advantage over a very short radiator.

If the radiator is a thin wire, bandwidth may be only + or - 1% of the
wire`s resonant frequency. Broadcast stations use towers of substantial
cross section as antennas. These provide several percent of bandwidth
and allow full audio range in the medium wave band.

A short antenna has low radiation resistance and high capacitive
reactance. This requires tuning out the large capacitive reactance
(small capacitance) with an equally large inductive reactance (large
reactor), and matching the very low drivepoint resistance of an
end-driven vertical to the higher impedance sending circuit. Resistance
involved in neutralizing reactance and matching the antenna to the
source is likely to be lossy for the too-short antenna. Walter has
already pointed this out.

Why would the EH antenna have interest?

Best regards, Richard Harrison, KB5WZI

Joe, W3JDR wrote:
"However, I don`t believe this was a 3 dimensional measurement, was it?"

Purpose of 3-D pattern checks would present high-angle radiation if it
exists as a possible source of night time interference. Primary service
only includes non-interfered ground wave coverage of a station.

Best regards, Richard Harrison, KB5WZI

On Wed, 14 Jan 2004 11:01:47 GMT, "W3JDR" wrote:
Richard:

"One can observe a gain relative
between two antennas and this would require significant differences in
the two patterns. "

I believe this is in line with what Ted says...the EH purportedly has
vertical adjustable pattern depending on the length to diameter ratio of the
cylinders.

That can only be a function of physical size and wavelength, or of
physical distance between sources (emitters) in terms of wavelength.
Neither condition exists (the antenna is small, and is only one
source). Beam steering and beam focusing antennas exhibit BOTH of
these characteristics, the eh neither.

"However, the data from the FCC methods of testing
prove there is no difference. "

Well, that's the way I interpreted the data too. However, I don't believe
this was a 3 dimensional measurement, was it?

Hi Joe,

There is little point in speculating about radiation straight up. If
that is the only benefit to the antenna, it is certainly no benefit to
the listener (definition of a Dummy Load). Field tests prove the
listener enjoys no advantage from this speculative gain.

Simple fact of the matter is revealed at the test site. Are they
using an eh, or the standard quarterwave over standard radials? The
acid test of capitalist greed has eroded these fairy-tale claims.

73's
Richard Clark, KB7QHC

Walter Maxwell wrote:
Richard, my point is that the EH antenna, as Ted Hart claims it, cannot exist.
He claims that by feeding the antenna with current lagging voltage by 90 degrees
it puts the E and H fields in time phase. This is impossible, totally violating
the principles of electromagnetic theory. Ted's claim shows misundstanding of
the theory of wave propagation.

Well Walt, look at it this way. By claiming he puts the E and H fields in
phase, he forces the ExH power flow vector to be equal to zero. :-)
--
73, Cecil http://www.qsl.net/w5dxp

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Walter, W2DU wrote:
"This is impossible, totally violating the principles of electromagnetic
theory."

I agree. It violates first principles of electricity. Radiation is a
resistive load. Voltage across the load coincides exactly with current
through the load. Volts and amps are in-phase. Nothing can be done to
change that. There is no electrical energy storage in a resistance.

Once you tune for unity power factor and match for power transfer,
you`re done and no monkey business will change the radiator from its
natural function. You put a voltage across its drivepoint and it does
its thing independent of how the voltage got there if the source can
supply the antenna`s demand.

Best regards, Richard Harrison, KB5WZI

And I almost had my Fractal, EH, CFA completed. Are you saying my dream of a
24 inch 5dBd gain 75 meter antenna has been shattered?

"Cecil Moore" wrote in message
...
Well Walt, look at it this way. By claiming he puts the E and H fields in
phase, he forces the ExH power flow vector to be equal to zero. :-)
--
73, Cecil http://www.qsl.net/w5dxp

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Richard Clark wrote:
"If you want to crow about your EH/POS DX contacts 1 mile out, they
better be in the direction of that nearby standard quarterwave antenna."

All that needs to be done to take the standard quarterwave antenna out
of the picture is to open-circuit the vertical to ground. That makes it
resonant at about 2X the frequency where it is a 1/2-wave at resonance
and capable of absorbing energy which it reradiates as a parasitic
element. This may not be so good for the 2nd harmonic in some direction.

Best regards, Richard Harrison, KB5WZI