JIMMIE wrote:

Recently heard about EH antennas and have done some research into them
including reading some articles in this newsgroup. It is begining ti
sound very much like my friends homemade FM/TV antenna. My friend being
short on money fastened an old bicycle rim to a piece of galvanized
pipe( axel stuck in the pipe) Feedline was connected from the center o
the wheel to a point on the outer rim. I had repeated told my friend
that something like this would never work and he demonstrated to me
that it did.. I theink the EH antenna is a lot like this old wheel,
just about anything placed on a mast with work to some degree. In this
case a very poor antenna allowed my friend to receive 2 TV stations and
4 or 5 FM radio stations. This was a vast improvement over the 0 tv and
Fm stations he was receving before putting up his "antenna" Would it be
appropriate to say that an EH antenna is more like a coupler that
utilises the antenna support structure(tower/mast) and feedline as the
radiating elements of the antenna?.


Jimmie,

There have been, and will continue to be - a lot of discussions about the
EH-Antenna. Some of the discussions are bordering to physical wars and
other postings are just plain simple stupid. As usual in other words...

One of the thing that are once and for all settled is that the antenna
function does not rely on coupling to other metallic objects. That myth is
so totally debunked so I won't even go there. Another fight is regarding
the efficiency.

The current discussions surrounding the EH is about any possible phase shift
as the main reason for the function.

If you are interested inthe EH-Antenna for hamradio use, browse to
www.eh-antenna.com. If you intend to use it commecially, it's patended and
you need to buy a license or a ready made antenna.
The EH is used for RFID and for vehicle communication as well as telemetry.
The ham EH's are only a very small fraction of the market.

And no, I don't think your friend made up an EH antenna.

There are some tests done in Radcom and possibly other ham magazines.

The EH-Antenna is just another small antenna with it's preferred field of
application. It's not to be compared with any directional antenna as it's
mostly omnidirectional. Also, the EH have to be mounted 1/4 wavelength up
to work according to the designers.

The EH that receives most of the appraisal is the 160m version. Probably
because it's very difficult to have a dipole or longwire up for 160m... so
when compared to a 160m dipole 10 meter above ground, the EH outperforms
that dipole... When comparing antennas close to ground, it's often a case
of "the least worse" functioning antenna and the EH performance is reported
to deteriorate lesser than wire antennas when close to ground and have a
better S/N.

The VHF EH's outperforms most typical VHF omnidirectional antennas even i
the difference in size is not that great compared to traditional antennas.

Very few hams are neutral in the view of the EH antenna so be prepared to
whip up a storm if you build one and claim success or failure.

BTW! If you intend to try for yourself, do not use ferrous material for the
build. That will bring down the resulting bandwidth by 70% or so!

Also, a dipole or wire antenna gives you a multiband antenna, especially
with an antenna tuner.
The EH is a single band antenna only and cannot be tweaked by an antenna
tuner. For a complete coverage of the HF ham bands you need many antennas.

Cheers


Dan / M0DFI