Ocf antenna theory book

The latest resource for the study of antenna theory. The socalled ocf windom is also a misnomer, for the same reasons. Our ocf dipole on 80 metres will work as well and have exactly the same characteristic as any dipole on 80 metres on the higher harmonics the ocf will become a progressively longer antenna. Sep 22, 2016 there is an explosion of available books and articles on the subject of antennae and antenna systems. The carolina windom thus becomes a nearomnidirectional antenna. Understanding antennas for the nontechnical ham by n4ja.

It is an off centre fed dipole, with 10 feet of vertical radiator. If your are serious about playing with the design of the ocf antenna on your own, do yourself a favor and invest in a good antenna analyzer which can scan the hf spectrum. I like to do business with people like you and i will be sure to tell all my friends about you. The ocf fd4 fd3 windom antenna fd4 80402010 m the 4band fritzel model fd4 is a special version of a windom antenna. Ocf dipoles about windom antennas and ocf dipoles, tricks on covering more bands moving feedpoints and potential problems. Off center fed dipole installed and written april, 2007. Antenna book, basic antennas compendium and classics series rsgb publications practical wire antennas and hf antennas for all locations cq communications sevicks and maxwells books on xmsn lines, baluns vertical handbook, all about quads 20. The idea for the antenna came from qsos with european radio amateurs who said they were using the fd3 antenna. A halfwave dipole is usually fed at its center because this is where maximum current occurs. The arrl antenna book for radio communications arrl 7.

After investigating the fd3 3band 402010m ocfd, he came up with a way to add the 15m band and the g0fah 4band antenna was born. D prasad, watrren l stutzman, samuel silver, cinstantine a balanis and robert s elliot. Used a g5rv for years then had a break of some 20 years. Offcenterfed dipole antennas category is a curation of web resources on, ocf dipole, the six meter ocf sleeve dipole vertical, centerloaded offcenterfed dipole 6 band. Shop our selection of alpha delta wire antennas, including multiband sloper antennas for limitedspace applications and swl antennas for superior performance through 30 mhz. Pvc coated wire, with every copper strand tinned to prevent corrosion. Using eznec, the design of an ocf dipole allows many variations in overall antenna length, height and feed point to achieve the desired result. The higher the frequency the closer the feedpoint must be to the center of the current maxima on that band.

Theory and construction of multiband antennas that cover multiple entire harmonic hf bands without the need for a tuner. Theory and construction of a novel trapless centerloaded offcenterfed cl ocf dipole or windom antenna for the 80, 40, 30, 20, 15 and 10m hf amateur radio bands new carolina windom antenna pdf file by qrp expressions by by n. Windom, w8gz who first published details of his antenna design in 1929. New material includes smart antennas and fractal antennas, along with the latest applications in wireless. Many people are quite happy using compromise antenna designs like an ocf. A lot of experts have memorized the text book theory, but havent actually built even half of the stuff they talk about. Ictpituursi school on wireless networking for development the abdus salam international centre for theoretical physics ictp, trieste italy, 5 to 24 february 2007.

Some tweaking may be needed, but mine was built within an inch or two of those measurements. Here you can downkoad the antenna and wave propagation or antenna theory and design books free pdf by all famous writer like k. It is in a condensed form and the antenna theory is explained so most hams can understand it. Resources listed under ocf antenna category belongs to antennas main collection. The choke balun at the bottom of the 22 feet radiating vertical effectively isolates it from the coaxial feedline going down to the transceiver. I have two standard textbooks on antennas, namely, antenna theory by balanis and antennas by kraus both third edition. About the buckmaster ocf dipole antennas buckmaster ocf antennas work mutiple bands and are made from the best quality materials.

Wanting to discuss ocfds and singlewirefed windom antennas. Ocf 4 bands 406 hf windom antenna polystealth ni4l. After spending some time modeling ocf antennas, the closest antenna i could find to a true multiband dipole with reasonable swr on most bands had an 80%20% leg length and 200ohm feedpoint. Theory, techniques and validation, world radio books, sacramento, ca, 1996 ford, steve, wb8imy, the classic multiband dipole antenna, qst, march 2004, pg. The long end was tied to a tree, again, using insulated rope, and with maybe five. He is a fellow of the ieee and served as president of the ieee antennas and propagation society in 1992. Len carlson, k4iwl smithe windom six band hf windom antenna. An antenna system is the antenna and everything else between the antenna and the radio. Clerks in radio stores told me that this book was outselling other titles 2.

In theory, with suitable selection of the feedpoint tap point and antenna length. The windom is just a horizontal halfwave of wire on the lowest frequency of. The arrl antenna book uses the formula carr gives the figure as 0. As a result of recent growth of the wireless market, research and development in antenna technology is proceeding at a fast pace. All our models have strong flexible wire and come ready to go with no trimming, no assembly, and no external connectors.

These are preliminary notes, intended only for distribution among the participants. It was with surprise and delight that i noted that clerks in one radio. Off center fed dipole antenna for the hf bands and 6 m, from 3 to 54 mhz. We must position the feedpoint and select the antenna length to place the feedpoint at or near a current maximum at every desired operating frequency.

It also works fine on all bands above 40m with a tuner, and even below 40m on 60m, and 80m, although the coax losses will be higher. Dec 11, 2015 the antenna can be installed in an inverted v configuration keeping in mind that this design changes the feedpoint impedance and will tune differently. In summary, offset feeding causes the antenna to be loaded differently. Before we tackle the claims made about the ocf antenna, lets start by saying that it will work, but not significantly better than a dipole of the same length. This is a very desirable characteristic on the lower bands 40 meters, 80 meters and 160 meters. Oasis christian fellowship, a ba christian fellowship originated from saudi arabia 2003 and spread throughout the philippines. The antenna impedance matching components box z above to match the antenna impedance to the coax line impedance usually 50 ohms. Choose from ocf, vertical, loops, zepps, end feds using palomar engineers overengineered to outperformtm impedance transformers and feed line chokes for outstanding antenna performance. Portable wire antennas is described on the amazon site as.

It will also appeal to practicing engineers working on antenna development. Windom off center fed antennas radios amplifiers baluns. They confirmed that the types of people who buy the book meet the profile above. Ham radio antenna wifi antenna radios hf radio zero point energy dipole antenna nikola tesla receptor witt the zeropoint energy field and how to exploit it unexplained experiment always precedes theory. The text explains both the basic theory of antennas and its application to practical designs. Study of the off centre fed dipole antenna g8ode short long feed point the off centre fed halfwave dipole the offcentre fed halfwave dipole, more commonly referred to as the ocfd, is very popular because it offers good performance as a multiband antenna using an antenna matching unit in conjunction with a 4.

Off center fed antenna, a dipole antenna with specific placement of feedpoint allowing multiple resonances in hf band. Dont know the maths or the theory, but this antenna works as well as a g5rv. Study of g0fah off centre fed dipole ocfd 40m20m15m 10m g8ode version of 4. This website is intended to be a source of knowledge for learning about and understanding antennas. Ocfs are derived from the windom antenna, a 1929 concoction using a single wire feed attached to the antenna. Ocf hf vertical dipole higher performance, hf multiband dx flagpole antenna covering 3. Stealth antennas the columbia amateur radio club presents.

They have no external connectors and a permanently sealed white pvc weatherproof center enclosure containing the potted autotransformer acting as 6. New material includes smart antennas and fractal antennas, along with the latest applications in wireless communications. After installing the ocf, check the resonant frequency on or lowest swr for 80 meters. This is a first reason why it pays off to build your ocf dipole with 80 m as the fundamental wavelength and not, for example, 160 m.

On the other hand, an ocf dipole is an ungrounded dipole antenna fed with. The effect is most pronounced at the fundamental frequency. Since the ocf antennas have a good match on their intended bands running 150ft of low loss coax is not a big deal except for maybe 10m the feed point is close to 200 ohms and you could probably use ladder line to a tuner but a problem i see is the antenna is unbalanced and there will be common mode current on the ladder line that could cause. If we first assume that all radiation occurs in the antenna element and none in the feedline, then we discover that the gain of an ocf for the same frequency at the same height is 7. It is a halfwave long on the lowest frequency, and is fed from a coax cable through a transformer inserted in the wire at onethird from one end. He is coauthor of the textbook antenna theory and design, john wiley, 1981 and 1998, and author of polarization in electromagnetic systems, artech house, 1993. For nonresonant end fed antennas, the typical feed point impedance is 300 to 600 ohms and a 9. Kraus this text is for the course on antennas offered to the seniorgraduate level by most electrical engineering departments. So for 80m and up, you have one leg that is 45 feet long, and another leg that is 90 feet long.

In a discipline that has experienced vast technological changes, this text offers the most recent look at all the necessary topics. Understanding and building the ocf dipole internet archive. Our 20foot verticaldipole performs with confidence. I have an 80 meter ocf dipole, that was about 2830 feet high thats now been raised to about 4547 feet. Its a grounded vertical wire connected to a horizontal portion acting as a top hat capacitance. Antenna theory fullwave dipole if the length of the dipole, i. An off center fed ocf dipole fed at the 23 point is resonant based on total length, and instead of a 75 ohm feed point they have anywhere from 200 to 600 ohms. In any illustration, the sketch drawn to represent the radiation of an antenna is its radiation pattern. Homemade carolina windom antenna m0ukd amateur radio blog. The short end was placed at about 40 feet off the ground, tied to a tree limb, using about 10 feet of insulated rope. When the original windom antenna was developed around 1923, the idea was to take a half wavelength of wire, and feed it at a point along the wire that would have near equal impedance on all amateur bands at the time i. On a half wavelength piece of wire, there is only o. Understanding antennas for the nontechnical ham old.

The discipline of antenna theory has experienced vast technological changes. Homemade carolina windom antenna m0ukd amateur radio. Harmonic operation of ocfs theory up, up, and away or harmonic. To accommodate the four bands, the overall length of the antenna 20. This is the standard against which to measure the performance of ocf antennas. It does provide clear easily understood explanations on the principles of antenna operation, transmission line considerations, impedance matching, baluns, tuners, and the pros and cons of different types and configurations of wire antennas. Hamcall a comprehensive world wide amateur radio callsign database with over 2,300,000 listings 7band ocf dipole antenna 80 meters through 6 meters with just one wire annual stockholder reports an internet annual report archive dating back to 1995, 10ks back to 1993.

Can the ocf antenna be used for portable operations. An additional reason will be given in the section about centerloading. Getting back on the air researched several wires which would fit my garden, tried a homebrew carolina windom and hey presto its a gem on all bands but top band. If feeding the antenna up to a ratio of d1d2 of is more convenient to the shack, then do so. Well the ocf is a halfwave dipole on the lowest band of operation. In response, constantine balanis has updated his classic text, antenna theory, offering the most recent look at all the necessary topics. On the other hand, an ocf dipole is an ungrounded dipole antenna fed with twinconductor line, either coaxial or open wire parallel conductors. It should be in the low portion of the 80 meter band e. I suggest you study its theory of operation for a better understanding of how these antennas are supposed to work and perform. New coverage of microstrip antennas provides information essential to a wide variety of practical designs of rectangular and circular. Ictpituursi school on wireless networking for development the abdus salam international centre for theoretical physics.

Radiation is the term used to represent the emission or reception of wave front at the antenna, specifying its strength. Ocf dipole this is a popular antenna design as the performance is very good across the hf bands and requires little or no tuning. The fabulous dipole ham radios most versatile antenna. Jun 29, 2014 the 7 band ocf dipole antenna was erected at 25 to 30 feet, on a hill side, using a military style push up mast, with a few customization on it. Full text of understanding and building the ocf dipole. The antenna can be installed in an inverted v configuration keeping in mind that this design changes the feedpoint impedance and will tune differently.

Ocf 8 bands 1606 hf windom polystealth antenna ni4l. Its 90 feet behind the house, most coax buried under lawn until it goes up the tree to the antenna. Antennas 101 28 useful references and books arrl publications antenna book, basic antennas compendium and classics series rsgb publications practical wire antennas and hf antennas for all locations cq communications sevicks and maxwells books on xmsn lines, baluns vertical handbook, all about quads 20. Buckmaster international llc, publisher of hamcall, annual. The 7 band ocf dipole antenna was erected at 25 to 30 feet, on a hill side, using a military style push up mast, with a few customization on it. Understanding and building the ocf dipolewant to build a simple, efficient, multiband antenna. We offer a variety of multiband and allband dipoles that provide great receiving performance with low swr. Yes, either our standard ocfs 300 or 3,000 watt or our qrp up to 100 watt model are excellent for portable operations. The success of the three previous editions of practical antenna handbook has been most gratifying. Folks, those of you in restricted areas can enjoy a little more confidence working dx from 806m. But if i could keep only one book, i would definitely choose balanis because, in my nonexpert opinion, it is more coherent, more systematic, and has a stronger emphasis on principles.

The ocf dipole is a compromise design hf antenna which allows operation on several bands without using an antenna matching unit atu. The modern common windom antenna is not an original singlewire fed. It all started with the windom antenna windom antenna the windom was once a very popular multiband antenna. Antenna looks to be very well put together from high quality components.

A wellconstructed 7 band offcenter fed dipole, designed for 7580, 40, 20, 17, 12, 10 and 6 meters. What is the best book regarding antenna systems excluding. Balanis the discipline of antenna theory has experienced vast technological changes. The earliest the arrl antenna book on my shelf is the 5th edition from 1949. I suggest you study its theory of operation for a better understanding of. Understanding antennas for the nontechnical ham by n4ja an. Unfortunately nobody has yet written a text book that shows us how to use modern lightweight material for building antennas.

A windom antenna is a singlewirefed antenna which is worked against ground. Hence, the best installation for an ocf is a matter of convenience. This book is about common medium wave and high frequency short wave antennas, but the theory presented here relates to antennas of any frequency. This new text is an introduction for undergraduates and engineers and is designed to give the reader a reasonably paced introduction to the theory that underpins antenna design techniques. While moving the antenna higher and farther from tree limbs i decided to ground it. What these numbers have in common is the belief that the feedpoint is the 300ohm point along the antenna element. Realizing many hams are mathematically challenged, only simple mathematics procedures are used. Keep in mind an ocf is a compromise antenna by design, so thats exactly what you are getting.