20 meter antenna pdf

Hamstick dipole is a practical and portable limitedspace. A trapped dipole is a dipole with blocking filters fitted at the operating wavelengths. This antenna may be built as a 20 meter, 17 meter, 15 meter, 12 meter or 10 meter monoband vertical antenna. A great portable antenna that i will use often at montrose harbor along the. Construct a compact, 20 meter rotatable dipole antenna of durable weather worthy components supported at a single point obviating the need for multiple supports and multiple support ropes crossing the yard. Another dis advantage is that considerable care is required in construction. You are now the proud owner of a comtek 20 meter vertical antenna. Ver2calwire antenna actuallyaver2callyorientated resonate12wavedipolewith theearthbeingthe return half duetopoorground conduc2vitya. The article also suggested using wider spacing with transposed feed. The nvis antenna described is based on the proven information from the military as2259gr antenna. Taking the opposite case, a 40meter dipole fed with 80meter energy has a low radiation resistance but very high reactance. A short, offcenter fed dipole for 40 m and 20 m by daniel marks, kw4ti version 2017nov7 abstract. An effective 1020m dx antenna for deed restricted lots.

A compact 20meter vertical dipole for stealth and portable. I had used cubical quads for many years and the decision for 20 meters and up was easy, but what to do. Given the lower swr is to the left of my target shortening the antenna seems to be the means to shift the swr to the right, correct. Antenna was up about 45 feet on tree branch wire length was about 52. The 20meter dipole including feedline and string weighs in less than my portable manufactured antenna and the 80meter job is not much heavier. All antenna lengths in the information below are in feet and are the results based on the standard formula. Antenna is a square configuration with equal size elements and a stub to lengthen the reflector. Measure 206 1116 inches from the end of each wire, and cut the wires to this length. It is very simple and efficiency yagi antenna with wide pass band. I chose this length on purpose to allow the system to be tuned to resonance with an antenna runer. The 20 meter vertical loop antenna will get you around the world if the conditions allow it.

Ur0gt match is used for matching the antenna with a coaxial cable. The described below helical antenna for the 20 meter band has small sizes, as well it is very easy to tune and moreover the antenna has high performance at the band. Of course, with a vertical element of approximately 15. This horizontal slot antenna, cut into the reflector of a tv dish, is both the master of disguise and high in performance. It is made to be hung in the rafters or from the ceilings. It is small enough to fit inside the attic of many homes. So a full size 3ele 20 meter antenna will be pretty big and will likely require you to add some roof strengthening by putting wood bracing across the trusses. On 20 meters, this antenna shows negative gain over a dipole.

The antenna offers a gain of about 10 db, is lightweight, mechanically strong and rivals the performance of similar commercial antennas. Falcon radio antenna 20m this is an indoor, outdoor apartment, house, condo, attic or garage, 20 meter 12 wave dipole ham radio transmitting antenna for the usa and uk. Manually trimming and tuning the elements to resonant frequencies on the bands they are cut for. A helical loop antenna for the 20meters band nonstop systems. The isotron 201510 combination antenna system requires only 1 feed lines and one metal mast. We will look at the elevation plots of the antenna at 33 feet then at 66 feet for the bands 80 40 20 15 10 meters. I first got the idea for a mini antenna from frank, g3yccs article in the qrpp quarterly, june, 1996. Hf antennas especially stealth models for those in an hoa. I sub sequently decided on a free standing halfwave 20meter vertical due to it having a reasonable antenna length and no need for a counter.

Antenna consists of from a vertical radiator v1, helical inductor l1, antistatic resistor r1, antenna grounding. A 20 meter moxon antenna moxons work great and they take up less space than full size two element yagis. Hall, k1td senior assistant technical editor and retired associate technical editor the purpose of this paper is to provide general information about communications effectiveness as related to the physical height of antennas. While a long wire antenna gives a pattern that breaks up into lobes, folding the same length of wire into a loop frustrates lobe creation and provides a nearly omnidirectional azimuth pattern. If your hf rig has a builtin tuner, the useable frequency span approximately doubles without significant loss of antenna efficiency. It will provide excellent short range communications and is easy to set up for emergency or temporary communications. Russia, siberia where i could not receive the sanction to installation for a fullsized hf antenna on the roof of. Ver2calwireantenna actuallyaver2callyorientated resonate12wavedipolewith theearthbeingthe return half duetopoorground conduc2vitya. The second area in which a long wire loop offers advantages is in azimuthal coverage.

I feel i have not done to bad wit the antenna at this height, contact to belgium, croatia and saudi arabia to name a few. Hanson, kj5vw austin, texas imitation, it is said, is the sincerest form of flattery so let me begin by pointing to the direct source of my inspiration for building this antenna. On 20meters, gain of the 20 through 10 meter transposed feed lazyh is much less than a regular dipole. Loops a e have sides approximately wavelength but overall circumference delta loop is the same as an equivalent quad on the same frequency, i. Full band coverage on 20 or 17 or 15 or 12 or 10 meters with swr under 1. I wanted high efficiency 40 meter antenna with lowangle radiation. For example, a 40 and 20 metre trapped dipole would have traps installed at the 20 metre points which would prevent the 14mhz band, effectively shortening the antenna. A practical nvis antenna for emergency or temporary. Construct a multiband offcenterfed ocf dipole covering the 40, 20, 15, and 10 meters amateur radio bands, and possibly the 6 meter band but that is considered a bonus band, outside the main project objective. A little tripod wont cut it and a roof tower is a lot more expensive than the antennna you are contemplating.

The 20meter whips measured about 100 khz, the 40meter at 40 khz and the 75meter about 20 khz. Acenterfeddipoleandcanbeconstructedasamulfbandantenna. Cut to be resonant at center height 16 feet with ends at. Here is a handy chart for determing 14 wave verticals, 12 wave dipoles, and full wave loop lengths. A decent antenna for that band needs to be much longer. An ontheair comparison was made between the portable whip dipoles up 20 feet and halfwave dipoles for 40 and. Figure 1 a comparison of the lower radiation angle and greater gain of the moxon red compared to the dipole blue. Wire antennas for limited space audio systems group.

Lower frequencies will pass the trap effectively making the antenna bigger. A ten meter vertical antenna for all license classes by rich kr7w the intent of this article is to show how i built an effective 10 meter vertical antenna. Or outside on the roof, or between 2 trees or the side of a wall, or whatever you can imagine. It must be made of durable, high quality, weather worthy components. I have ignored the warc bands for simplicity but, first, some basic antenna theory. But if you are looking for a compact, mulitband solution to your antenna situation, consider this amazing option. This shortened easytobuild vertical, with noradials, is made from surplus military camouflage poles. Additionally, the mystery antenna is designed to work at least as well, on the other hf bands as a g5rv. Single band antenna when fed by coax works good for multibands when fed by open wire line and using a tuner how to build one can be found at. Automatic band switching is accomplished through the use of hygains hyq traps. A dipole design for the 20meter band is an efficient and inexpensive antenna for the novice and veteran ham enthusiast alike. Chapter 1 general information general this antenna model is a twoelement tribander designed to cover 10, 15 and 20 meters.

The eh antenna concept is the most significant change in antenna theory in more than. My top five backyard multiband wire hf antennas old. A short, offcenter fed dipole for 40 m and 20 m by daniel. The w5gi multiband mystery antenna is a fundamentally a collinear antenna. Every antenna above real ground has a pattern that is affected by its height above ground by its length, and by its orientation. A multiband resonant nvis plug and play dipole for 20,20 digital. Strip 12 inch of insulation from both ends of each wire. Before adjusting the 40 meter i would complete the tuning of the 80 meter first.

My first contact to australia was on my 20 meter loop, so it has to be working great. Neither has a balun too heavy but both have a couple of rf choke ferrites on the coax, probably more for mental attitude than anything related to physics, but half of success is attitude so what. In either case, the antenna current and therefore the radiation is very small. My first 20 meter delta loop was mounted kind of low to the ground, but it did okay. The mystery antenna, on the other hand, presents a sixlobe pattern on 20 meters, gain broadside to the antenna, and also low feed point impedance to simplify matching the antenna to the rig. The antenna gain is about 3 dbd on 14 mhz, or half the radiated power of a regular dipole. Antenna height and communications effectiveness by r.

High performance 40 meters vertical without radials. Lets see on the schematic of the antenna figure 1a. My goal is to reveal, in some kind of logical way, my thoughts, methodology, and how i came up with the final result in an easy to understand way. Please see individual antenna listings for more details. The g0kya efhw an endfed half wave monoband hf antenna. A ten meter vertical antenna for all license classes. The kj5vw 20 meter mini yagi the kj5vw 20 meter mini yagi gary r. The antennas low cost is made possible by modifying a radioshack fm broadcast receiving antenna rs 152163.