Hello All,

I am trying to build a 40 meter EH Antenna. I've been following the directions in the pdf bood written by Ted Hart (W5QJR).

On page 26 of the pdf book there is a section labeled "Tuning An EH Antenna".

I've been trying to follow the instructions but I am very new to building antennas and the instructions just are not adding up for me. I cannot make procedural sense out of what is stated in the pdf book.

I have the antenna mostly built. Tuning has become a road block for me.

My setup is as follows.

The Phase coil is between the top radiator and the bottom radiator. A radiator is a piece of aluminum sheet wrapped around the pvc. There are two as I understand it. A top radiator and then a phasing coil 1/2 diameter down from the top radiator. Then another radiator below the phasing coil by approximately 1/2 diameter. Then the tuning coil about one diameter below the lower radiator followed by a source coil approximately 1/2 diameter below the tuning coil. Bottom of phasing coil is connected to top of tuning coil by a wire running down the middle of the pvc. Bottom of tuning coil is connected to a wire that is attached to the top of the bottom radiator with a wire running down the side of the inside of the pvc. From all of the diagrams that I have seen, this is the basic setup of an EH Antenna. I am not trying to do anything different then what Ted Hart states in his pdf book.

There are three sub-sections under "Tuning An EH Antenna":

1. Frequency of Proper Phasing

2. Impedance Matching

3. Adjusting the Source Impedance

I am having trouble with all three of these sections. I haven't even got the the other sub-sections and may have trouble there to. Time will tell.

So, for sub-section Frequency of Proper Phasing, what is the "clip lead on top the tuning coil"? Does that mean that an alligator clip is attached to the top the tuning coil? If so, this is not where my maximum radiation is found. It is much lower in the tuning coil wraps and not at the top of the coil.

How I am currently tuning the tuning coil is that I have an alligator clip from the center post of the so-239 to a spot on the tuning coil that is giving me higher radiation than other spots on the tuning coil. I also have the bottom of the tuning coil and the wire that comes from the top of the bottom radiator connected to the ground of the same so-239 connector.

The Source Coil is not connected when I am looking for the maximum radiation in the tuning coil. I do not know if this is correct or not.

It is not clear in the directions if the entire antenna should be connected (i.e. top radiator all the way to source coil). It seems like when tuning the tuning coil, the source coil isn't yet attached. It simply is not clear to me in the pdf book.

Likewise, in the Impedance Matching section, what is actually connected when doing this step (i.e. top radiator to source coil, etc.)? The pdf book states, "The goal is to adjust the antenna to provide an impedance of 50+j." What is being adjusted on the antenna? Is the alligator clip I was using to find the maximum radiation in the tuning coil being moved around to now find where 50 ohms is found in the coil? If I move the alligator clip, I loose the setting for maximum radiation. Is the impedance and maximum radiation both found while moving an alligator clip around on the tuning coil? From the pdf book, it is not clear how the antenna is being adjusted or what is being adjusted. Likewise, it is not clear if the maximum radiation point on the tuning coil needs to remain connected while finding the impedance level of 50 ohms. Moreover, it isn't clear what is being adjusted to find impedance.

The next section, "Adjusting the Source Impedance", am I trying to find 50 ohms in the Source Coil while it is not attached to the tuning coil and the bottom radiator? Am i finding the 50 ohm mark on the source coil while it is simply wrapped around the pvc and and not attached to anything? What and where is the "feed tap"? The pdf book states, "...while keeping the frequency of the transmitter at the maximum radiation frequency is to observe the VSWR and adjust the feed tap for minimum VSWR." No where is "feed tap" explained, therefore I cannot adjust it. I cannot ascertain where or what the feed tap is, how it is connected and what it is connected to?

I know this got long. But I am completely confused as how to tune the antenna. I am using a frequency generator and an Field Strength Meter (FSM). Nonetheless, they are just paper weights right now because I am not sure what the setup is when using these two tools: frequency generator and FSM.

I sure hope someone can clarify the procedure to tuning an EH Antenna.

Just to state the obvious, I am asking clarity on Ted Harts tuning instructions and procedures. I am not asking if an EH Antenna can be tuned or if they even work. I would like to determine that for myself. If you have comments or an opinion on EH Antennas, please save that for another post. I want to determine for myself if an EH Antenna works for my needs and situation. I am simply asking for clarity on Ted Harts instructions and procedures for tuning an EH Antenna. I am not asking for opinion or clarity on why EH Antennas break all known physics and antenna theory.

Thank you kindly,

John - KF7PVL