VE3SQB ANTENNA DESIGN PROGRAMS
Hams go where no engineer has gone before.
FOR THE EXPERIMENTER
The 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.
The log periodic antenna is the ultimate broadband beam. It can provide high gain on a single band or moderate gain on multiple bands. On vhf you can easily design a single feed 2 and 6 meter antenna. On hf the size and element diameters are usually a drawback .Wire versions are usually the answer. Although 4 bands is usually stretching it, don't be afraid to try more. I had an inverted 'T' loaded 13 element designed for 160 to 6 meters and it worked. It covered an acre ,was 120 feet wide ( 40 meters), 350 feet long (105 meters) and was suspended from 3 towers. The 1/2 mile of wire looked like a suspension bridge. The neighbours are still cautious to talk to me and the XYL doesn't want to discuss it.
The program may be obtained free from Degen Antenna Designs HERE
This should work on most Icom radios but has only been tested on a 746Pro. Please inform me of your results and any bugs.
While designing and testing new antenna designs, it became evident that an accurate method to measure the antenna was required. Professional Field Strength Meters can run $3000 or more and professional software was also expensive. Several shareware programs on the net are available but use the radios computer interface to measure s-units which is not accurate or even use the audio volume which may be fine for SSB and AM but not usable on FM. My software uses an A/D convertor and can be connected to a receivers s-meter or better to the squelch test point or directly to a Field Strength Meter (BEST). It will accept voltage inputs from - 10 to + 10 volts. The trace on the picture (3/4 actual size) is of the received signal of the NOAA17 weather satellite taken from the squelch of a Hamtronics R139 Weather Fax Receiver. The full 360 degree sweep represents a horizon to horizon signal. THIS IS the only software that I distribute as shareware. It may work on homebrew A/D convertors and some commercial brands but was designed to be used with the DATAQ convertor priced at $24.95 USD and available from their website. The trialware has a 14 day limit so it would be best to have the convertor first. You can download the trialware HERE
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