ANTENNA DESIGN PROGRAMS
With surface mount technology
and microcircuitry, most hams no longer build their own equipment. One
area that is still open to amateurs is in antenna building!
To get you started, I have made up programs that cover the most common types of antennas and a few experimental designs. Click on the icons to download. The programs do not write to the Windows registry so just delete the files when you no longer wish to keep them.
These programs do require that the dll files are up to date, so if you are unsure or the programs do not run, download the full install version of HFQuad2002 first, then all will run..
Most programs have inch and metric calculations.
The Standard quad is designed
from the textbook equations and is compliments of Roger Clement KC5LCA. It
is designed for 50 ohms and is the tried and true method.
covers all the common types with a coil calculator built in for the
antennas that require them.
Homebrew capacitors, gamma match and homebrew feedline.
If you don't have the means for measuring reactance, resistance and capactance on your antenna, the gamma program will give you a starting point for for designing the gamma match.
Single line next to the tower, twin ladder line, 4 wire line and even HOMEBREW HARD LINE can be designed with the Feedline program.
Back in the days when CB was at its height, with CBers in the millions, the antenna companies strived to build the best. Two interesting designs emerged. Avanti Antennas produced a little quad called the PDL-II. This quad , fed by 2 coax lines, was able to work both vertical and horizontal. Its "co-inductive" secret was that it used a folded dipole to feed the quad. This gave the antenna more gain than a simple quad. I modelled the program to find out how it worked. The loops of folded antenna have been replaced by V shaped elements without any changes and easier matching. This antenna is worth experimenting with especially with its reduced size. Co-inductive and PDL-II are trademarks and this antenna is most certainly covered by patents.You are allowed to build a not for monetary gain, experimental version for yourself.
The other antenna was made by Antenna Specialist who are still in business and may still produce the Super Scanner. This antenna beams into three quadrants without the use of a rotator. By using relays, a single feed line could be switched to 1 of 3 elements or to all for an omni position.The coax jumpers made the other 2 unactive elements appear to be longer and act as reflectors. Later versions grounded the inactive elements through a tuned capacitance/inductance circuit. I found that the jumpers work better at times when made of 75 ohm coax. This antenna is recommended for advanced antenna builders only as it is VERY sensitive to element length and spacing changes. Some adjusting will probably be required. This antenna and the name SuperScanner have patents and trademark restrictions.
No patent, trademark or any other type of infringement is intended against the Antenna Specialist Company!
As soon as I saw QUAD in Quadrifilar Helicoildal Antenna, I had to investigate it. Used for weather satellite reception, this omni directional antenna has everything you want. It is small in size, has a very low angle of radiation and up to twice the normal verticals gain.
The program has 6 variations of the design, with different formulae for each. This is the most interesting design I have ever researched. After 200 hours, the program is still in the research stages but I have discovered many points about its operation and decided to post what I have.
There is no construction or matching details in the program yet, so check out qha sites on the net for this info. I built a 2 meter desk top version out of foam disks and 20 awg wire. Wrapping the coax around the 3/8 fiberglass pole about ten times was good enough to reduce the match to 1.5 over a mhz. It measures at 5.1 db gain and I can work all the local repeaters and about 15 miles simplex with the antenna sitting on the BASEMENT floor. It also appears to work like a discone on receive.
Receive is good outside the band both above and below the 2 meters.
It easily hears from 137 to 174 mhz. The use of small wire instead of tubing did not affect the bandwidth but it did shift the frequency down about 3/4 of a mhz. To correct this, I found that shortening the large loop shifted the frequency much more than changing the small loop. THIS IS VERSION 3 ...... All except the RCA version are designed to be made out of 3/8 inch tubing which is easier to work with.
The dimensions are NOT designed for use with elbows or bent radius corners. Cut the tubing 1 diameter longer than the required length , flatten the ends in a vise and drill bolt holes at the correct dimensions. After assembly you may still solder the joints. All are designed to be used 5 meters or more above ground. Patterns and phasing are lost if you place them on the ground. Using an A/D converter hooked up between the receiver and a computer plotted out the receive pattern of the 1/2 turn .3 ratio Wxsat Qha mounted 20 feet up on the rooftop. The pattern was almost identical to the modelling results shown on the patterns page. The signal is solid from horizon to horizon , being out only seconds from predicted passes.
NEW Matching calculator for low impedance QHA ...HERE
the Qha, I wanted something easier for checking out circular polarization.
I discovered that 70% of all commercial FM radio stations run circular
polarization. Home receivers are usually horizontal while mobiles are
vertical. After looking up the types of antennas they use, I came up with
two designs. The first has as much gain as a QHA but is much easier to
build. I recommend this to new builders as small errors will not greatly
affect performance. The QHA can be rendered useless by errors of only a
few millimeters. The FM station antennas use a round horizontal element
which is difficult to scale and build. By changing the elements to square,
the antenna scales from 500 to 1 mhz and is easy to
second antenna is even simpler, consisting of only two bowed elements.
While not as good as the first , it still shows promise and anybody could
build it. Although originally designed for 137.5 wefax reception, circular
polarized antennas can make nice standby omni antennas to monitor band
openings, both horizontal base, vertical mobile communications or even for
a beacon xmitter.
The omniquad is a very
simple but excellent standby vertical antenna. I've built many over the
years but just got around to making up a program. The main advantage is
the extreme bandwidth. Make all the dimensional errors you want, and it
will still work. You can use wire or tubing. A broom handle ,some 1/4
dowels and under 10 feet of wire will make a 2 meter antenna. There is
very little gain or pattern difference between the 3 and 4 sided versions
but the 4 sided version does give a better match. It can even be used as a
desk top antenna.
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