Ham Radio

There are new antennas that go under the names:

Crossed-Field Antennas
US Patent 6,025,813
 Australian builder of Crossed Field Antennas
Article on theory of Crossed Field Antennas part one from AntenneX Magazine
 

&

E/H Antennas
 US Patent 6,486,846

These antennas are considerably smaller than the conventional Hertzian antennas.

 I have built an E/H antenna for 20 Meters. It performs with a strange enigma, local stations are down in the static but distant ones although weaker are better in signal to noise ratio than my rooftop dipole.

For instance I can receive Havana Cuba and the Caribbean Islands clearly just holding this antenna in my hand on the ground floor of my house. However a signal from Jim VE4MT of 150 watts and a beam pointed right at me is just barely detectable from a distance of 1/2 the width of the city.
 
 

Photos of antennas built by Willard Elliott
 

Constructed Nov. 11 2002

Constructed Feb. 20 2004

Three views of my 20 Meter antenna


 
 


.
The above antenna has been used for 2 way contacts from Winnipeg to
New Tripoli, Pensilvania
and Hallifax Nova Scotia
from inside on the second story
 
 

The Antenna below was constructed March 5 2004

This version is for 80 Meters

Here is a closup of the input Coil assembly

Here is another view of the coils

Those are ordinary hair combs to get the required turn spacing of 0.125 inches

This antenna outpreforms my 35 foot outdoor vertical while sitting on my coffee table on the ground floor
 
 

This is my new design of the 80 meter antenna
January 16, 2005

Here is a closup of the coil section







Many people think a radiator this small is imposible and the only way they work is that the feed coax is radiating.

Here is proof that that is not true    Added on March 11, 2003

Here are links to E/H Inventor Ted Hart  and some builders of E/H Antennas:

 Jack Arnold W0KPH an expert on E/H antennas

 Stephano Galastri (Italy)

 Antenna for Packet Radio

 Test of an E/H antenna as compaired to a GP antenna

Lloyd Butlers Page VK5BR

Larry D. Brown'a Web Page Excellent builder of E/H antennas

 New design for the Star Antenna  December 2004

      I have removed my previous theory due to having received information that the width of the radiators controls the beam width. If the radiators are reduced from 7.5 inches to 4.5 inches the antenna can be used for local transmition and reception. The 7.5 inch radiators are best for DX as the signal goes directly to the ionospere. I plan to do some testing of the antenna to deturmin the pattern of the beam with various radiator lengths.
 

 Willard Elliott May 19, 2003
Tests

I am now building 3 versions of this antenna for 40 Meters. One will be the Ted Hart Network. One will be a coax delay. And the final one just a matched link. We will compare the three versions. After discussing the antenna with a friend of mine who is well versed in RF we came to a conclusion. It would seem that the 90 degree delay theoretically does nothing for the antenna. A capacitor feeding the E field is still a capacitor feeding the E field whether it is delayed 90 degrees or not. The matched link should be just as good.

 Willard Elliott   November 25 2002
It is now proven that a matched link is better than the 90 degree delay.
Willard Elliott January13th, 2004
Feb 10th Update

By experimentation it has just been found that the beam width is deturmined by the distantce between the center of the radiators and the center of the resonant coil. The beam width is appearently the result of the offset between the Electric field and the Magnetic (H) field. These are radiated in a cancellation manner such that, if the resonant coil is between the radiator tubes the radiation is virtually cancelled. The fact that the coil is not in the center of the radiator tubes but is beyond the end of one of them, results in some radiation that is not cancelled. This is the beam.  This beam is much narrower than previously assumed* and results in communications that are received by relatively few hams. However when a signal is propagated both hams have a good strong contact and the signal is relatively noise free.
Tests will now be conducted to find out what this beam width is.

Willard Elliott  Feb. 10, 2004
*Ted Hart has given figures of 18 to 24 degrees above the horizon as the beam width.

Magnetic loops

As a comparison to Crossed Field see the  Magnetic loop antenna

A new loop antenna with pin diode tuning is patented #6,304,230

This page last updated December 16, 2006
This page is composed by Willard Elliott
E-mail w.elliott@earthlink.net