I hope you enjoy vhfuhf so much that you eventually step up to longboom yagis with lots of gain. Welding rods make great elements, especially brass or stainless in the 116 to 18 range. Building a wa5vjb cheap yagi 1296 mhz edition the wa5vjb cheap yagi is a simple and elegant design. Since ive mentioned that, ive gotten several requests for the information. The first two antennas are on the workshop roof with the help of my little helper nathan and my big helper sam. I got most of the way up the ladder when my knee told me that going further was a terrible idea. A ham known as kent britian wa5vjb, came up eith tables containing element lengths and spacing in inches. Cheap yagi for 70 cm build this cheap and easy satellite. Yagi design to go with 433mhz tracker post by lamp.
The shield of the coax goes near the center of the top of the element. This antenna is ideal for rovers, and is good for a fixed station on a budget. I cut and mounted all the elements, but frankly, the feed system is a bit more complicated than i would like so i didnt get it finished. N5em even built an array of 16, 1 1 element versions of these antennas for field day. I have built a number of yagi antennas for the vhfuhf bands, including air traffic control, fm broadcast and military bands. But if you just cant for some reason, get on with whatever you have and enjoy yourself. We didnt use the yagi very much during the chase as katherine and i discussed earlier, we ended up relying on the egg beater for most of the tracking. Kent originally designed these antennas for weak signal work. For the local s2s events, consider enhanced antenna options. The shield of the coax goes near the center of the top of the. A portable yagi antenna for working amateur radio satellites. Cheap yagi for 70 cm build this cheap and easy satellite downlink antenna by richard f. I know that mcmaster carries copper and brass rods, too. Wa5vjb cheap yagis wood boom a couple of weeks ago, i started working on a version of the dl6wu yagi that i might be able to get going for this weekends moonbounce activities.
This post describes the second of two ground antennas that we used during the stratoballoon chase. The directors are pretty short at tv channel 14 and are helping a little bit, but not much. I f ham radio satellites have always seemed out of reach for you because of cost or complexity, theres something you should know. Dual band 2m70cm yagi with duplexer posted on 5 april 2014 at 19. A threeelement yagi is easy to build with materials you may have around the house, and improved vertical antennas are an easy way to go as you dont have to point them one example is the mfj1714. You can build a wa5vjb cheap yagi for literally a few bucks. These j driven elements usually bring several comments from people new to cheap yagi s. We know this is a small consolation to the members that flooded, but we want to do what we can to get you back on the air quickly. Yagiuda antenna driven element impedance question on. Yagi design to go with 433mhz tracker australian rocketry. Remebering that the velocity factor is 23 in coax cable, or the speed of light 200 instead of 300. The yagis are offset, by 90 degrees so that is the offset already. I dont have an swr analyzer for that task so ive just got 11 elements and 4 elements vertically polarized on 70cm and 2 meters respectively. Relatively high gain 2 meter antennas are not all that big.
Wa5vjb cheap yagis wood boom fred and lisa spinner. I have built about 6 of these antennas out of 1 x1 or 2 x2 lumber scrap. I am building a pair of 6 elements for stacking sidebyside in vertical polarization and trying to confirm the relationship between the driven elements. Also, it makes an excellent school, club or boy scout project. Wa5vjb cheap yagi cheap yagi antennas for 2m, 220, 440. The measurements for element lengths and spacings have been copied from the amsat wa5vjb cheap yagi design check the links section. The antennas were designed with yagimax, tweaked in nec, and the driven elements experimentally determined on the antenna range. Field day, i built a kent britain wa5jvb 1296 mhz cheap yagi. This manual augments the original online documentation available from. The measurements for element lengths and spacings have been copied from the amsatwa5vjb cheap yagi design check the links section. Cheap yagi antennas for vhfuhf by kent britain, wa5vjb edited by john maca, ab5ss. Originally published in the central states vhf society conference proceedings, 1994. Element spacings on cheap yagi 432 vs 435 vs 440 vs 450.
During their session, they had several of the students put together 440 mhz yagis. Cheap yagi antennas for vhfuhf by kent britain, wa5vjb edited by john maca, ab5ss editors notes. Club project yagi kent britain wa5vjb this antenna has been built in over a dozen meetings as a club project for new hams. After looking around at commercially available antennas, i decided to build one myself with some of the plans that are available online. Actually, its official name is the controlled imped ance yagi because of its wide bandwidth. Sam got on the roof yesterday and mounted the antennas for me. Controlled impedance cheap antennas kent britain wasvjb if youre planning to build an eme array, dont use these antennas. I have a 3 gang variable capacitor from an old radio, gonna try a tape measure mag loop for hf recieving. Ive also mentioned on occasion that you can build a satellite 2m440 yagi for about the same cost. Impedance matching is fixed in the design through a jpole driven element. Antenna systems for portable, mountaintop and rover. See also wa5vjb cheapyagi pdf for another article on the same antenna. I used the 144 mhz and the 435 mhz amsat measurements. I want to add the following link for quagi antenna projects.
Virtually no ham antenna article today lists all the materials, tools and speci. Simple, cheap, and can be built in three versions for a few bucks. R f news 2 rf bytes members, whose station were affected by the floods, can check out equipment from our radio loan program with the rental fee waived. As hf band conditions deteriorated, and my interest waned, i started looking into 6 m, the magic band. I attended vhf 101 put on by marshall williams, k5qe, and kent britain, wa5vjb. This project is an ultra portable dual band vhfuhf yagi antenna for working amateur radio satellites. The simplified feed uses the structure of the antenna itself for impedance matching. But, i also like to have a coax connector at the feedpoint. Hello, just needed to order a stash of different aluminium parts from a warehouse and thought adding some stuff for a diy yagi antenna construction, to make the shipping price less % of the whole order i thought it would be kind of handy for me to make. Antenna was designed by kent britian, wa5vjb, and full credit and blame belongs to him on this design. Those in the northern tier of the us or in a good part ofthe us this winter are experiencing brisk winds, temperatures dippingsouthward, piles of snow or ice, or heavy rain. While it is practical on the uhfmicrowave bands to use a copper driven element, it is less practical on the 144 and 222 mhz bands. James duffey, kk6mc, photo a beginning rover station often con sists of an allband transceiver, such as an icom ic70670007100 or a yaesu ft857897, and simple antennas for one or all of the 50, 144, and 432 mhz bands.
Time and weather finally allowed me to finish off the tv antenna conversion to a three element yagi using the halffolded dipole for the driven element. That, of course, led to entering vhf contests, which initially held the same interest as my earlier hf contesting this time putting more new grids in the log. Based on wa5vjbs design, n3ltv and i worked out a spreadsheet excel 2009 or later to modify the numbers so we could pick a 420450 center frequency for the antenna. Using the same boom, the student can build one in a matter of minutes for 432 mhz weak signal, amsat, or for the fm repeater band. You can learn all about them at cheap yagi antennas. The second project of the day was a dual band antenna to try to hit amateur satellites with. You can carry an assembled 11element yagi or 8element quagi for 432 on the back seat of your car. Controlled impedance cheap antennas kent britain wasvjb.
This works and is simple enough, but you cant get the elements close enough to couple much 01 the power into the vagi structure. Youll find the dimensions and construe mhz spreadspectrum cheap yagi. These j driven elements usually bring several comments from people new to cheap yagis. I built the 4 element version of with 10 awg romex, and pvc i measured very accuratley but the. Wa5vjb cheap yagis originally published in the central states vhf society conference proceedings, 1994.
Yagiuda antenna driven element impedance question page 1. My first controlled impedance yagi was made for 915mhz spread. Radio contesting journey hf, vhf, roving icom america inc. Vhf 101 and vhf contesting a first look at weak signal vhf. The antenna that i build is an 8 element uhf and 4 element vhf arrow. Unlike the egg beater, which is an omnidirectional antenna, the yagi is a directional antenna. Portable operation can be considerably easier and setup faster than for hf.
Up at 700 the antenna room by kent britain, wa5vjb a cheap and ez hdtv antenna project photo a. Cheap antennas for the amsat leos kent britain wa5vjb. Kent britain wa5vjb cheap leo antenna drew, ko4ma, using the cheap leo antenna during a dayton amsat leo demonstration. The diplexer is not shown in the images, check the wa5vjb pdf for diplexer. The antennas described in this article were built as. Both yagis will require a 14 wavelength of 75 ohm coax for each feed. I learned about cheap yagis for the first time at the central states vhf societys 2014 conference.
He got a lot of inquires on yagis for the fm section of the bands. While there are plenty of high performance antenna designs. The calculator will give you the basic dimensions, the gain, bandwidth, and vswr. Both yagiss should then have the same length of coax coming from each one. The wa5vjb cheap yagis are a great way to get on vhfuhf without spending a fortune on commercial antennas. There are plenty of stand alone and online yagi antenna designers.
If youre feeling a chill in the air, it must be time for the januaryvhf contest. Build the one for 450 as that is designed for the fm band. The dimensions in the pdf file cited at the beginning of this page for the. I dont know the history of the development of the arrow antenna, but the model suggests that the dimensions for a 435 mhz yagi using insulated elements were used for arrow, but mechanically the elements were made electrically part of boom.