This is about a 1hour project, or maybe a little extra to check swr and trim the wires to the correct length. Solid aluminum ground plane for 6 meters so239 connector gp121. Eventually some drastic changes to the configuration led in the right direction. These inexpensive antennas offer a gainantenna basestation solution thats durable and effective. These inexpensive antennas offer a gain antenna basestation solution thats durable and effective. Technically, the jantenna is an endfed l antenna thatuses a l matchingstub. This is the 54 34 hollow tube that is threaded on the inside at one end. Radio amateur, outdoor antenna, ham radio antenna, circuit design, microsoft excel, coups, home brewing.
An antenna ground plane is not to be confused with an electrical ground. Online and downloadable dipole, inverted v and ground plane calculators. Ground currents all around the antenna make the image work. Ground plane antenna calculator resource detail the. The measurements below are for building a simple dipole antenna. Its just one end of my g5rv dipole, or sometimes called a dummy loadread more. Blog antenna ground plane calculation arcadian antenna.
Dec 30, 2015 another little application written to help aid in vertical antenna construction. This is derived for the 2m vhf of amateur allocation, 144 mhz 148 mhz. I needed a good 2m antenna to hit the callaway amateur radio league carl clubs repeater, about 5 miles away and found the 2 m ground plane project. Spacing is the distance from the boom to the gammamatch. Mfj 1750s offer a shuntfed matching network that will handle up to 300 watts. At three times this frequency 435 mhz, the antenna will be resonant again. Courtesy of and designed by n2imf joseph r mielko this downloadable calculator will provide you with good starting measurements for a basic ground plane, inverted v or standard dipole antenna. Download the ground plane dipoleinverted v calculator by n2imf. By on4cfc via antennex super jpole antenna collinear design by kb0yki vhfuhf antennas by kb0yki jpoles, super jpole, omnidirectional, quads, yagis vhf eggbeater antenna from on6wg f5vif quick and simple 2 meter ground plane project via hamuniverse 2m. You get mfjs rapidtuneradiator for quick accurate tuning. Whilst this is true as far as it goes when you use a vertical antenna on a harmonic like the quoted 15m on a 40m vertical or a 2m ground plane on 70cm the radiation angle is quite a bit higher. For vhf and below, as the elements get bigger, some more structured design is needed. Mfj 1750 2m 58 wave ground plane antennas represent one of the best values in 2meter base station antennas.
A vertical antenna with radials bent down at approximately 45 degrees will have a natural impedance around 50 ohms making it a good match to the radio in use. Dx engineering receive antenna systems feature the best designs available for hf dxing, as well as for am dxing on the mw broadcast band and for the short wave listening bands swl. Bandwidth is much narrower than a centre fed dipole due to the tuned matching. Free online engineering calculator to quickly estimate the geometric size of a j pole antenna. This type of antenna is very easy to build and i recommend all beginners to give it a try.
It will have a freespace radiation pattern like this, for an antenna oriented vertically along the zaxis. Antenna experts manufactures ground plane antenna for 3066 mhz. A simple ground plane antenna you can buildfor 146, 223 or 440 mhzin no time flat. Design and adjustement is easy, as with the capacitor you can tune the resonance by some mhz with no effort. Mfj 1750 2m 58 wave ground plane antennas mfj1750 free. In this case, its a multiband antenna the customer is using it can be used from 700 mhz 2700 mhz so the ground plane required could be anywhere from 464 square inches. Free online engineering calculator to quickly estimate the geometric size of a jpole antenna. A ground plane antenna is a form of dipole antenna designed to work with an unbalanced feed line. Antenna projects for 144 mhz category is a curation of 148 web resources on, the tiny 3, magnetic loop for the 2m band, feed line dipole for 2 meters. Radial slowly twist the wire while pulling it to keep it taught. Free online engineering calculator to quickly find the dimensions of a hb9cv antenna. Online calculator for logarithmic periodic dipole antenna lpda.
Chip antenna performance depends a lot on ground plane size. Building a 70mhz quarter wave ground plane m0ukd amateur. The half wave antenna mounted 1 foot above ground shows only 1. Enter the frequency in mhz and click calculate it will give you the length for the radiating element as well as the ground plane elements. The vertical element and radials are 332 or 116inch brass welding rod. Use our simple calculator to determine approximate dimensions of materials needed to build a vertical antenna. It uses a matching system similar to jpole antenna. For a situation where the signals of interest are below the antenna in elevation e. Does mounting a ground plane antenna upside down change. Adjustable quarter wave ground plane antenna with images.
As ground plane size differs vastly from the antenna evaluation board, antenna efficiency and bandwidth will suffer. The radio waves from an antenna element that reflect off a ground plane appear to come from a mirror image of the antenna located on the other side of the ground plane. Simple to make 2m 70cm antenna project for portable use. Maximize your signal and minimize noise with antenna accessories such as antenna switches, vertical addon kits, variable phasing controllers, baluns, radial. Radial attach each radial with a 632 screw, lockwasher and nut 20.
Oct 02, 2014 simple 2 meter ground plane antenna project with pvc support by kc0ynr, malcolm here is a very simple 2 meter ground plane project that can be used as an emergency antenna, in limited space, for quick and easy setup on field day, camping, or just plain outdoor fun. The amountsize of the groundplane required for the optimal performance of a monopole antenna is determined by the frequency you are transmittingreceiving at. The ground plane antenna is designed for unbalanced feed cables, like a coaxial cable. I have made a page showing some images and construction details. Note that the quality of the other half of the antennathe conductive ground plane beneath itmakes a big difference in both the efficiency and feedpoint impedance of the antenna. Amateur quarter wave ground plane antenna calculator. You get shunt fed matching network for lowest possible swr over entire 2 meter band.
Even after much effort the antenna simulation program did not give the desired result. This calculator can be used to design a quarter wave ground plane antenna, with radials. I recently built a quarter wave ground plane antenna, so that i could get back on the 4m 70mhz band. Other 58 waves cant work any better no matter how much they cost. The ag series is range of omni directional unity gain ground plane antennas that are ideal for local area coverage. This calculator is designed to give the vertical length height of a quarter wave ground plane antenna, and the length of each of the four radials. Raising the antenna above ground over a counterpoise of elevated ground wires can increase efficiency and input impedance. A typical mobile cb antenna does not transmit horizontally, it radiates in a downward pattern. The results are conveniently displayed in inches, centimeters, feet and meters. Dipole, inverted v and ground plane antenna calculators.
As groundplane size differs vastly from the antenna evaluation board, antenna efficiency and bandwidth will suffer. The image antenna just represents all of the currents induced in the ground all around the antenna. The normal quarter wave ground plane antenna consists of a vertical radiator which is insulated and centered between 4 horizontal surrounding. If you are just getting experience in building antennas or you are an old pro, here is a simple and fun project. This means that the power is being radiated to a large degree up towards the sky which may or may not matter on 15m at various times but it. Mfj1756 instruction manual 6 meter ground plane antenna 8 tuning the antenna after the antenna base with radials has been secured to the mast, refer to chart 1 to tune the antenna to the desired frequency. Here, youll find links for antennas covering 30 mhz and up. Whats the difference between a dipole and a ground plane. Thebasic j is reported to have 3db of gain over a l ground plane antenna and 6db over an isotropic theoretical antenna. There are usually four radials, three being a minimum, but you could use up to six.
A ground plane antenna project for 10 meters band by n4zaw. It is found that for a monopole antenna like a quarter wavelength vertical, the ground acts as a plane to reflect the radio waves so that an image of the top half of the antenna is seen in the earth. How to calculate or estimate surface area of required ground. As the name indicates the antenna ground plane acts as a simulated ground. What is the theoretical performance of a 2m 14 wave. Choose from quarterwave, halfwave, the powerful 58wave, 34wave, or fullwave, and calculate minimum lengths of required radials, and then shop for your needs on our other pages and select from our inventory of aluminum, fiberglass, wire, coax, connectors, and other parts and. Chipantenna performance depends a lot on groundplane size. Pay no attention to the wire goingoff horizontally from the base. In addition, specific models mentioned in the antennas forum at radioreference are linked here for future reference if youre a newcomer or old hat, or anywhere in between, when installing antennas, safety first. Online calculator jpole antenna designer changpuak. I have made a page showing some images and construction details of this antenna which can be seen here. Antenna calculator and design software electroschematics. An monopole antenna does not reach ideal performance until the ground plane is infinite, and the ground plane can be arbitrarily reduced in size and it will still work in theory although at some point in practice, the feedline, or the earth, becomes a better ground plane than the ground plane. Download the ground planedipoleinverted v calculator by n2imf.
That image isnt an actual current or dipole at the position of the image antenna. The changes were placement of a ground plane short at the tip of the tash spiral and tapering the element in a logarithmic fashion. The ground plane as described should as easily be used on 220 or 440 mhz without modification, although if you use it only on those bands, you could save some realestate by. Ive been reading up on 14 wave ground plane antennas to build for 2meter and 70cm. It has two electric poles charged positive and negative.
Fig25simple groundplane antenna for the 144, 222 and 440mhz bands. In the ground plane antenna style whip antenna, the plane consists of several wires. Ceth60 frequency counter diy mini vhf frequency display preamplifier prescaler. Calculate the dimensions for a slim jim or j pole antenna for hf, vhf or uhf. Ground plan element dimensions for various local australian and some international amateur radio bands with 4nec2 an nec based antenna modelling and optimizing computer application the proposed 14. The horizontal radiation pattern is a circle where the antenna radiates equally well in all directions.
Magnetic loop antenna calculator spreadsheet excel spreadsheet that help. This calculator is designed to give the vertical length height of a quarter wave ground plane antenna, and the length of each of the four radials often called radiators for the frequency chosen. A ground plane antenna is more of less one half of the dipole and mounted above the ground plane. The first online dipole and inverted v calculator on the page below has been around for many years and is. Ideally for radials you should have them sloped downward at a 45 degree angle to help provide a better match. To attach the radials to the flange of the so239 i use small boltnutlockwasher sets in 440 size about 12 long. Hf dipole antenna this antenna software will help you design a simple wire dipole antennas for 1 30 mhz. Dont forget to include an additional height above ground for the lowest horizontal element when determining the total vertical dimension, usually six or seven feet for safety reasons. Apart from the list appeared above we are experts to design and supply the ground plane antennas for out of bands antenna. The ground plane antenna consists of a vertical rod lifted by four radials. A metal surface the larger and flatter, the better is required underneath the cb antenna to launch the signal out into the atmosphere.
Feb 20, 2014 easy to build ham radio dual band 2 meter and 70 centimeter ground plane antenna. It is the most effective antenna when compared to other ground plane antennas. In this publication i explain how to build a very light weight, cheap, easy to build and deployable in 30 seconds portable vhf antenna for the 2 meter band. The image antenna for a dipole over perfect earth is a dipole at the same distance below. You can solder the radiating element directly to the connector and use the. The antenna calculator above uses this formula as a starting point to calculate wire lengths for the dipole. This formula to obtain the length of a halfwave dipole antenna will give a good ballpark value to start with. Before starting to build the antenna, you can stiffen up ordinary 14 gauge copper. Technically, the j antenna is an endfed l antenna thatuses a l matchingstub. At 145 mhz, the 14 wave vertical, plus the image antenna formed by the ground plane, make it effectively like a 12 wave dipole. When mounted on the 4radial portable ground plane described above, the same antenna shows 1. Im going to use a small ht 5 watt and am in the middle of suburbia, so im trying to maximize performance of the antenna wherever possible.
The computer shows a ground plane antenna mounted 1 foot above ground has a gain of 2. A typical gain pattern for a quarter wave ground plane antenna is. Feeding the antenna can be done at the director or at the reflector. When 8 radials are used instead of 4, the swr improves to 1. A ground plane antenna by definition gives you a ground plane, but still, if you antenna has a good ground plane there should be only marginal deferences. Enter the resonant frequency for the dipolevee antenna calculation. Download software 14 wave antenna with ground plane.
Maple leaf communications antenna calculator vertical. A quarter wave monopole mounted against a perfect ground will have an. Listed under the antennas antenna calculators category that is about antenna design calculators. A 12 wave antenna isnt dependent on a good ground, it isnt as prone to lose power in a poor ground situation. For this weeks project, we will be building a 14 wave ground plane antenna. Antenna design calculators category is a curation of 83 web resources on, parallel square conductor transmission line calculator, analysis of antenna mast strength and bending stress, full wave loop antenna calculator. Slimjim 2m antenna sperrtof 2m antenna aka sleeve dipole or sleeve jpole. Thebasic j is reported to have 3db of gain over a l ground plane antenna and 6db over an isotropic theoreticalantenna. The chicken wire wonder a unique broadband vertical.
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