Håller på med ett projekt om EH-antenner som kommer att bli klart till sommaren.
090409. Nu har det material kommit som utgör 80 % av bygget för EH-antenner kommit.
Så nu kan planering börja för konstruktion och dokumentering av antennerna.
Mina demo antenner kommer att bli för 14, 50, 144 mHz i olika tappningar.
Beskrivningen kommer att presenteras på denna sida då allt labbande har gett det önskade resultatet.
Conny / SM5DCO
Sidan EH-antenner är under konstruktion. Kommer att
innehålla byggbeskrivning m.m.
W5QJR, has released a backpacker antenna design. See his web site http://www.eh-antenna.com for more EH-antenna information. This is Jack Arnold W0KPH version of his design.
The antenna is 22 inches tall and built on one inch PVC pipe. (actually 1.34 inches) The cylinders are 7.5 inches long, and spaced 1.34 inches apart. The cylinders are made using a thin copper foil purchased at my local hardware store. A 12 X 30 inch piece costs about $10.00.The coil was wired with #14 bare copper wire. After you have put the cylinders on the PVC pipe, measure the capacitance between the two cylinders. You will need this value to compute the phasing network...If you don't have the equipment to measure the capacitance , 7pF will get you close enough..
I spaced the wire on the coil, using some heavy cotton thread found in my XYL's sewing basket.... When I finished winding, I removed the thread, and coated the coil with hot glue... The Trimmers caps are 350 pF compression caps purchased at a local radio components store...
The only problem in building the antenna was the feeding of the wires inside of the PVC pipe. I really don't have any suggestions on an easy way to do this.
The Network Design program was used to compute the values of the components. The two step 'L' and 'T' filter was used. the L was set to 50 -25 ohms and the T filter 20-30 ohms. Most of these antennas will measure 30 ohms radiation resistance... The measured capacitance between the two cylinders on my antenna was 7pF. Compute the values of the coils and wind them...
When you finish building the antenna, I tuned it this way.
Place the antenna in the open away from obstructions. Disconnect the LL coil from the 'L' Network, connect the MFJ 259B to the lower end of the coil(the big one), and adjust the number of turns on the coil until you get X=0 at the desired center frequency. The bandpass of the antenna at the 2:1 Points is about 250KC each side of center. 'R' will be in the range of 30 ohms....Once you have the coil ,adjusted Set the input cap, 'CS' to the design values ,225 pf for my antenna. Connect the L section back to the T section. Now put the antenna on the pole and adjust the second cap,'CL' for a 1:1 SWR at the design frequency.
I have not yet put the antenna on the air, We are having a heavy snow storm, and I don't want to go outside to adjust antennas. I did tune it up in the shack, and it looks good here. Once the snow quits, I will get it outside and see just what it will do.....
A Note Of Caution
Be careful around the upper coil and the upper cylinder. These
points are at very high voltage and you can get a nasty RF burn
2. Because of the small size of the capacitors, I do not recommend Transmitter powers of over 50 watts. The caps might go up in smoke at higher powers..
A 20 METER DIPOLE:
Now we will design and construct a very real and very practical 20 meter antenna.
This antenna can be scaled to other frequencies. For this antenna, purchase a piece of
plastic pipe that has an outside diameter of about 1 inch. The pipe is for water, thus the
pipe will be specified as an inside dimension. ¾ inch pipe will have an OD of about 1
Step 1. Wrap the pipe with aluminum foil, copper, or other conductive material to
make 2 elements spaced the diameter of the pipe. You can put glue on the pipe
or wrap the foil or metal with either clear tape or scotch tape. We had some
thin sheet copper, and that is what you see in the photograph.
Step 2. Measure the capacity between the elements. Ours has a value of about 7
Step 3. – Since we do not currently have an equation to predict the value of
radiation resistance, from experiments I can tell you it will be about 30 ohms.
Step 4. Now we have the necessary information to calculate the network values.
They are as follows:
· C1 = 225 pFd and must handle a current of 1.4 amps at 71 volts RMS for
100 watt transmitters.
E· C2 = 291 pFd and must handle a current of 3.4 amps at 133 volts RMS for
100 watt transmitters
Buy, beg or steal the necessary capacitors. Beware of the current rating for
the power you operate with. Any capacitor will work for QRP. Mica
compression trimmers are good for any power thru 100 watts.
· L1 = 0.92 uHy. This translates to 2.5 turns on #12 wire around the plastic
pipe. See the photograph for detail.
· L2 = 13.61 uHy. This translates to 21 turns of #12 wire around the plastic
pipe plus 4 turns between the antenna elements. Space the lower coil about
1 diameter below the lower cylinder.
Step 5.A – Tuning the antenna requires adjusting the amount of total inductance
to set the desired resonant frequency. Course adjustment is determined by the
number of turns, final adjustment is done by spreading the turns. Alternately, I
put a small piece of wire soldered to the lower cylinder and placed across the
gap. Bending that wire allows frequency adjustment of several hundred KHz.
Step 5.B – To achieve minimum VSWR it is necessary to adjust the value of the
T capacitor (C2) and where it is tapped on the coil. C1 can be a fixed value
because it is not necessary to adjust it. I prefer to do my initial tuning with a
signal generator and a simple diode field strength meter. The signal generator
allows changing frequency while the field strength meter indicates the
frequency of maximum signal, then the relative signal power while adjusting
the T capacitor. Antenna experimenters will have their own techniques and
test equipment. Final adjustment is then done by trimming the T capacitor and
spreading L1 for perfect VSWR. Once the VSWR is set, the frequency can be
changed over a wide range with almost no change in VSWR.
Step 6. Record the 2:1 VSWR bandwidth. This one measured 245 KHz.
Step 7. Measure the +/- 3 dB bandwidth. For this antenna it is 390 KHz, about the
same bandwidth as a full size dipole. This is a Q of 36.4. Now, since Q =
XL/R, then R = XL/Q. Since XL =1296, then R = 35.6 ohms. Since the RF
resistance of the coils is 2.18 ohms (from the program), the radiation
resistance is the total minus 2.18, therefore the radiation resistance = 33.43
ohms. For fun, compare that to the radiation resistance of the same antenna
length if it were a Hertz antenna. Previously we calculated a value of 0.124
ohms. Now, we can calculate the efficiency as RR/(RR+RL) = 94%. This is
equal to -0.27 dB, not bad for a very small antenna. Now you see the true
effect of the EH Antenna concept.
Step 8. Calculate the current thru the antenna. For 100 watt transmitter power it is
P = I^2R, therefore I = (P/R)^.5 = 2.8 amps. For 5 watts QRP it is 0.14 amps.
Step 9. Calculate the voltage across the antenna where V =IZ, where Z = the sum
of the radiation resistance and the capacitive reactance. For a100 watt
transmitter V = 2.8*(33.4+j1144) = 3204 volts. For QRP the voltage is 160
volts RMS. Just be careful of RF burns near the center of the antenna.
Instructions for building an L Tee Network Dipole
The basic dimensions for an EH Dipole for any Amateur Band are:
· Outer diameter of insulative tubing (non-RF conductive, if it gets hot in a microwave, don’t use it) should
be approximately the ham band divided by 10 with the answer in inches.
Example: 20 meter band 20/10 = 2-inches.
The above sizing will provide nearly all if not all the band to 2:1 VSWR or less.
The bandwidth coverage is directly proportional to the diameter to the antenna.
· The length of the elements for a standard dipole is equal to the circumference of the antenna.
For DX, make the elements longer. (Narrower beam-width).
For closer in coverage, make the elements shorter, (Wider beam-width).
· The spacing between the elements must be the same as the diameter.
· To start with:
Assume the antenna capacitance to be 10 pF.
Assume the radiation resistance to be 32 ohms.
· Use the EH Phasing Network Design in the Links section to calculate the network values.
The only change will be to split the LL coil and place at least last 4 turns of the coil between the elements.
This action causes the lead going to the top element to not have the correct phase shift so as to radiate
inside the lower element.
· For the capacitors used in the network we have had success using mica compression type. For sources of
this type, just do a search for capacitors on the Internet. If you plan on using more than 100 Watts you
might need a higher current rating.
· Now that you have the antenna built, it’s time to tune it.
First adjust the CL Cap. For minimum VSWR.
Next tune the transmitter to the frequency with the lowest VSWR.
Then with CS and transmitter, tune to the desired frequency.
Now adjust CL for minimum VSWR. If the minimum VSWR can not be reached within the limits of CL,
then the assumption of 32 ohms is not correct and you will have to go up/down on the CL capacitance.
· Antenna height should be at least 1/8 of a wavelength.
TUNING AN L+T EH ANTENNA
This note is intended to assist in getting the most from an EH Antenna. There are
four (4) components in the network, two capacitors and two coils. A previous note from
Stefano tells about an L+L network, so this note applies to the L+T network.
Unfortunately, all four components are interactive, and to make it worse, the
output impedance of the transmitter can have a major effect. We have provided a
program to assist in calculating the values of the components, and that is an excellent
starting point - if you know the impedance of the transmitter and the impedance of the
antenna. Unfortunately, the impedance of he antenna can not be directly determined, so
you need to make an educated guess. Most transmitters have an output impedance of
about 30+ ohms with some reactance. Therefore, there is some phase shift before the
network on the EH Antenna. Since we do not know the exact characteristics of the
antenna, there are now 6 variables. Just to make it interesting there is one more that is
new to antennas. The 7th variable is the amount of feedback between the radiating
elements and the network. Due to the location of the network coils and the lower
radiating elements, there is both capacity coupling and magnetic coupling. The spacing
can be varied to affect the bandwidth and radiation resistance.
Now that you are enlightened, we can begin tuning the antenna. The objective is
to obtain maximum radiation and minimum VSWR. When this is accomplished, you will
have maximum bandwidth for the system - unless you change any of the 7 variables. For
example, changing the power of the transmitter will change it's output impedance.
Changing any of the physical characteristics of the antenna will affect the necessary
tuning. Any conductive object (including your hand) near the antenna will affect the
tuning, primarily due to capacity. The capacity between the antenna elements is only a
few Micro-Micro farads, so any near object can change the tuning. This tells us that the
antenna should be hung from a rope as a vertical antenna away from all objects.
Fortunately, the E and H fields of the antenna are contained within the sphere of the
antenna, so we do not have a problem with the impedance of the antenna changing due to
distant objects, such as chain link fences, that do have an effect on Hertz antennas.
Therefore, the antenna can be tuned when hung from the ceiling inside the Ham shack.
Ham shacks come in two varieties – those with adequate test equipment and those
with none. For those with adequate test equipment – read on. We believe if you are a
dedicated experimenter you will have the test equipment and antenna related experience
necessary to achieve maximum performance from an antenna. If you are lacking both test
equipment and experience, we recommend you purchase either an antenna or a kit. The
kit will have the necessary instructions. If you read on you will understand why the test
equipment is required to get the most from your EH Antenna. You will also understand
that experience with RF and related adjustments is also necessary.
My definition of adequate test equipment is:
*) A quality signal generator with 50 ohm output and up to +20 dBm power output.
*) A frequency meter if the signal generator does not have digital diplay of frequency.
*) A VSWR bridge compatible with the signal generator (see the diagram of one on this
*) A good diode field strength meter.
*) A good capacity meter.
We begin the tuning procedure with the assumption that you constructed the
antenna with recommendations from this web site. We also assume you measured the
capacity of the antenna and estimated the values of the network based on either the Bingo
program or the one on this site. All that is left to do is to adjust the 2 capacitors and the 2
coils – only a combination of 4 items.
Because the signal generator has an output impedance of 50 ohms, the input
capacitor for the L network can be a fixed value, so now there are only 3 variables.
Adjust the signal generator to the desired frequency and adjust the capacitors for
best VSWR. Check the signal strength and ensure that maximum radiation occurs at best
VSWR. If the two do not agree and VSWR is not perfect, the radiation will be less than it
should be. If they agree and VSWR is perfect, you have arrived. If the radiation is
maximum when VSWR is minimum but VSWR is not perfect, you may need to adjust
the small coil to improve the VSWR. If that did not fix the problem, there are too many
or two few turns on the large coil. In other words, the antenna can not be matched at that
frequency. Now is the time to change the signal generator to other frequencies and try
readjusting. This will give a good indication as to the best frequency for your antenna.
Frequency increments of about 2% are recommended. After you have determined the
optimum frequency for that antenna, bring your antenna to the desired frequency by
adjusting the main coil (more or less turns) and resetting the capacitors.
Now that you have the antenna properly tuned at the desired frequency, you need
to carefully measure the antenna parameters. With this information you can determine the
true characteristics of the antenna. The data you need is:
*) Resonant frequency
*) 2:1 VSWR bandwidth
*) +/- 3 dB bandwidth
*) value of the T capacitor
*) value of the coils
To measure the +/- 3 dB bandwidth, note the value of maximum field strength –
then increase the signal generator output 3 dB. Measure the lower and upper frequencies
where the radiation is the same as before the 3 dB increase. The difference between the
two frequencies is the 3 dB bandwidth.
The inductance of the coils can be determined from the number of turns, spacing,
wire size, and coil diameter. Consult programs or handbooks to determine the inductance.
With this value calculate the value of inductive reactance at the resonant frequency. Use
this value to calculate the value of the tuning capacitor. It should be about 1.4 times the
measured value. If there is a significant difference, the cause needs to be determined.
Also, determine the value of the loss resistance of the inductors.
From the value of the T capacitor, determine the value of radiation resistance.
This can be done by playing games with the network program. Try various values of R
until the value of C is found to be the same as the measured value. The program should
now also indicate the amount of inductance you have determined.
From the value of radiation resistance and loss resistance in the coils, calculate the
system efficiency. If it is worse than 90% there is a big problem. Note – 90% is a loss of
0.5 dB – not bad when you consider there are 6 dB in an S-unit. .
If you think your EH Antenna is now performing properly, it is time to take it to
it’s final resting place and connect it to the radio. If the resonant frequency is not what
you want, the capacitors can be adjusted to make the VSWR better at the desired
frequency, or you can change the coil inductance. This can be done in several ways – a
copper slug can be moved in the coil to change the inductance, or a copper or aluminum
sleeve can be moved over the coil to change the inductance. The copper slug can be
moved by the use of a electric screw driver and a long threaded screw. The control can be
remote from the antenna. Fortunately, on the higher bands the instantaneous bandwidth of
the antenna allows full band coverage without tuning the antenna. On the low bands you
may want to place a series resonant circuit in the center lead of the coax. When the circuit
is resonant there will be no phase shift. As you adjust the circuit you are effectively
changing the phase between the current and voltage. This will alter the operating
frequency of the antenna. I have just presented two methods of remote control – your
We indicated previously that the output impedance of your transmitter may not be
the same as the signal generator. Therefore, you may need to adjust the L section
capacitor to achieve good VSWR.
If you have a problem with RF feedback, In another area on the web site we talk
about RF grounds for the antenna.
This may seem to be a lengthy process to achieve the desired results from an EH
Antenna. However, compare this to tuning and matching a 75 meter mobile antenna, or
installing a dipole and changing the angle to match the impedance and adjusting the
length to the desired frequency. Those things must be done outside, while the EH
Antenna can be tuned in the comfort of the Ham Shack. Also, if you do complete all of
the suggested steps, you will know the details of the performance parameters of you new
antenna, and that is more than you ever knew about a Hertz antenna.
There is one more important thing about building your own antenna, and that is
the satisfaction derived from building and using a portion of your Ham station.
And God Luck Conny SM5DCO
COMPUTING THE PHASING
Ted Hart W5QJR
CEO EH Antenna Systems, LLC
INTRODUCTION: Ham Radio has been a birth place for and nurtured many important inventions and discoveries. I have participated in some of those and benefited from others over the past 61 years I have held the call W5QJR. Although I have previously presented new concepts to Hams (including the Antenna Noise Bridge in 1967 and the small High Efficiency Loop Antenna in 1984), and written many Ham articles, I now have the privilege and opportunity to present one more, the most important, an antenna concept that will benefit every Ham.
I have invented and patented a not just an antenna but a new antenna concept, the first practical change in antennas since Hertz developed the resonant wire antenna in the 1880’s. What will it do for Hams? It will allow reduction in size and reduce received noise. It retains high efficiency, wide bandwidth and virtually eliminates EMI. Maybe size and improved noise are not important to you, but in this modern world many Hams are off the air because of restrictions on antennas. Those restrictions no longer apply.
Sound to good to be true? That is what many have said until they experience the EH Antenna. You can buy one from a company in Japan, but you can also readily build one with inexpensive materials. We will include details of one in this article and provide information that will allow you to build an EH for any Ham Band. You can even build and test one for 80 meters inside the Ham shack.
THE CONCEPT: All antennas to date have been based on the Hertz concept of resonant wires. Unfortunately those antennas have very large Electric (E) and Magnetic (H) fields near the antenna and do not create Poynting vector radiation until the fields have traveled about 1/3 wavelength from the antenna. This is called the far field boundary of the antenna. This is due to the fact that current is applied to the antenna. A changing current creates a magnetic (H) field. A changing magnetic field creates an electric (E) field. Because one field creates the other these fields are 90 degrees apart in time, thus the need to travel in time until they are in time phase.
Now, we will consider the EH Antenna concept. With reference to the drawing below, note that there is an Electric (E) field and a Magnetic (H) field. A high voltage is presented to the antenna which develops the E field. Since the voltage is applied to the center of the antenna and there is no voltage at the ends, the E field causes a differential voltage to be impressed along the length of the cylinders, which causes current to flow on the cylinders. That current is in time phase with the E field (it is developed simultaneously) and develops the H field which is also in time phase with the E field. Because the two fields are in time phase at the antenna, radiation occurs at the antenna. Because the two fields have the proper orientation relative to each other and are in time phase they satisfy the Poynting Theory at the antenna. This allows the fields to be efficiently integrated which allow the antenna to have high radiation resistance. Because the EH antenna has large cylinders (compared to wires), the capacity of the antenna is high. The combination of high capacity and high radiation resistance provides large instantaneous bandwidth and high efficiency. Further, because the radiating elements are large in diameter they can be very short relative to a wavelength, typically only a few percent. The diameter of the SFRT antenna is chosen to give the desired bandwidth at the lowest operating frequency.
In the drawing above note that the tuning coil inductance can be adjusted so that, in conjunction with the capacity between cylinders, the system can be resonant at the desired operational frequency. By selecting the proper tap on the tuning coil and the source capacitor a very low VSWR match to the antenna can be achieved. Typically the capacitor should have a nominal value of 200 ohms at the operating frequency. However, it is not critical and that allows a variable to be used. Varying the capacitor is much easier than changing the tap on the coil.
PERFORMANCE: The antenna provides exceptional performance and exhibits the following performance parameters:
ANTENNA SIZE: A small antenna will radiate and receive as well as a large antenna if it is properly designed. Small wire antennas do not meet these criteria.
INSTANTANEOUS BANDWIDTH: If you examine the EH Antenna it is a simple series resonant circuit (except for stray capacity). Therefore we can use the following simple equations to define the antenna:
Q = XL/R=XC/R=F/BW
Q is a measure of the antenna instantaneous bandwidth. At resonance XL and XC are equal. These are the reactance of the inductance and capacitance respectively at the operating frequency which is F. BW is the +? _ 3 dB bandwidth, nominally 3 times the 2: VSWR bandwidth.
C can be approximated by the following equation: =0.546*L*D+2.05* D where L is the length of one cylinder and D is the diameter of the cylinder. Then XC = 1/ (2pFC)
If we build the antenna and measure the 2:1 VSWR bandwidth, we can then gain a good estimate of the resistance of the antenna. By rearranging the equation above we have: R= XC BW/F. R is the total R in the circuit comprised of radiation resistance (RR) and loss resistance (RL)in the tuning coil. We can calculate XC, we know the operational frequency, and we can measure the bandwidth therefore we can calculate the resistance. Next, we need to know the loss resistance of the tuning coil. If we assume it is made of good wire and the length to diameter ratio is reasonable, the Q should be about 200. Since Q= XL/RL and we know XL = XC, then RL= XC/200. Typically, the loss resistance will be less than 2 or 3 ohms.
EFFICIENCY: The efficiency of the antenna can now be calculated as a ratio of the output power to the input power. Since RL is defined as the output and the sum of RR and RL is equal to the input power, the efficiency = RR/(RR+RL). The calculated value of R based on the measured value of bandwidth should be between 30 and 180 ohms depending on how the antenna is constructed. (more on that later). If we assume the loss resistance is about 3 ohms and the measured value of R is 30 ohms, the efficiency will be =(R-RL)/R = (30-3)/30 = 90% or -1/2 dB.
Antennas come in many physical configurations. We want to first detail a 20 meter EH antenna with the associated feed network that any Ham can easily duplicate. All you need is a piece of pipe about 1.25 inches in diameter that is made of insulating material such as wood or, preferably, plastic pipe. Each of the dipole elements for 20 meters will be about 7 inches long – yes, 7 inches on 20 meters – and can be made of aluminum foil from the kitchen wrapped around the pipe. You will need some wire – preferably #14 magnet wire as used to wind motors. The source capacitor needs to be about 47 to 56 pF. You can readily build the antenna and tune it in a single evening. Then you can test it to prove to yourself that it performs as well as that commercial 20 meter vertical (16 feet tall) with a large ground radial system.
After you have proven the concept to your satisfaction you may want to experiment with various sizes. Typically we prefer that each cylinder has a length about 6 times the diameter and the spacing is equal to the diameter. If you space the cylinders very close the capacity will increase, thus the bandwidth will increase and the loss in the tuning coil will decrease because there will be less wire in the coil. To do this, use a piece of glass for an insulator. Cut the pipe and use hot glue to secure the glass between the cylinders. As shown in the drawing below:
For lower frequency antennas use about 4 inch pipe on 40 meters for large bandwidth or 2 inch for small bandwidth. And double that for 80 meters.
MOUNTING: To gain the most from the antenna the location of the antenna can make the difference between performing well or poorly. We have not fooled Mother Nature when we built a small antenna. However, she will dictate the location of the antenna. If the antenna is mounted vertically for chasing long haul communications, then the height of the antenna should be at least 0.1 wavelengths above ground. On 20 meters that are only 2 meters. On 80 meters that are 8 meters. Since these are very low heights the antenna should be mounted high enough so that the communication path is not blocked by trees or buildings.
On the low bands, the antenna is excellent for rag chewing if it is mounted horizontal and above a reflecting screen. Aluminum screen wire works very well. The height need only be about 3 feet on 40 meters and about 5 or 6 feet on 80 meters. Tests show this configuration can provide more radiation than a ½ wave dipole.
FEED LINE RADIATION: Many Hams have complained about the coax radiating because there is RF current on the outside of the coax. When the antenna is high in the air it is not in free space. Consider that the top cylinder is operating at a high voltage relative to ground. This in effect says that there is a capacity between the antenna and ground. The RF current on the coax is the return current from that capacity. Unfortunately, it may be enough to alter the tuning. That means that you must do the final tuning of the antenna after it is placed it its operating position. Otherwise, it might as well be a wet noodle. Now you understand why a large number of Hams have to say that the EH Antenna does not work.
Let me put this in perspective – I built a 75 meter mobile antenna and placed it in a wooden rack on the back of my pickup truck. Below that is a sheet of aluminum to act as a reflector. Keep in mind this was an experiment. By comparative tests against a station with dipole 30 feet in the air this antenna gave equal performance. That may be big news to some of you, but the point here is that there was less than 5 feet of coax outside the cab of the truck. 5 feet of coax on 75 meters is not much, and certainly not enough, even if it were a very good radiator, to have a significant effect on the performance of the antenna. So much for those that say it is the coax radiating, not the EH Antenna.
A 20 METER DIPOLE – SOME TIMES CALLED A BACKPACKER: Now we will design and build a very real and very practical 20 meter antenna. For this antenna a piece of plastic pipe with an outside diameter of about 1 inch was used. The pipe is for water, thus the inside diameter is 1 inch (2.54 cm)...
Step 1: Wrap the pipe with aluminum foil, copper or other conductive material to make 2 elements spaced about the same as the diameter of the pipe. You can put glue on the pipe or wrap the foil or metal with clear tape or even scotch tape. We used thin copper sheet, so that is what you see in the photograph. Do not use any type of ferrous (iron) material.
Step 2: Measure the capacity between the elements – if you have that capability. Ours has a value of about 10pF. The reactance at 14 MHz is ohms.
Step 3: Wind a coil to tune the antenna. It needs to have a reactance of ohms which is uH. The estimated number of turns on the coil will be turns and cover about inches. The coil should be spaced about 2 diameters or more below the lower cylinder.
Step 5: Select a source capacitor of about 200 ohms reactance, which are about 56 pF. As previously stated, a small trimmer capacitor would work well and reduce the trial and error method of tapping the coil in the optimum position. Now, tap the coil at about 1/10 the way up to the coil from the bottom.
Step 6: If the feed wires are in place we are ready to begin the tuning process. To set the frequency best to use a Grid Dip Meter to find the resonant frequency, then adjust the turns on the coil to move it to the desired frequency. Best to remove turns from the top of the coil. When you get close then spread the turns for fine tuning.
Step 7: Adjust the source capacitor and tap to give a low VSWR match.
Step 8: measure the 2:1 VSWR bandwidth and multiply that value by 3 to give a good approximation of the +/- 3 dB bandwidth. We measured xxx KHz which results in a Q=
Step 9: Move the antenna to the final operating location, connect the coax and note the operating frequency and VSWR. If they have changed significantly it will be necessary to change the tuning and matching. This is best done by having one person at the radio and the second person at the antenna to make changes.
Step 10: Enjoy your wonderful small antenna.
You can find calc program on: http://sm5dco.
The EH-antenna book do you have here: Here!