Length is equal to 1/2 of the wavelength for the frequency of operation. 59 million miles on his Hi-Q-5/80 antenna bought nearly 20 years ago. A further factor which influences antenna resonant length is the diameter of the wire used for that antenna. The actual number needed depends on a lot of factors; the actual input impedance of the antenna, the size of wire, the overall length of the coil, its diameter, and whether it is insulated or not. The coax is tapped onto the coil at the 50 ohm location. Adapts import and domestic vehicles with separate turn and stop lights (3-Wire System) to standard trailer tail light wiring (2-Wire System) stop/turn light: 2. This is the Take it Along (TIA) portable antenna which helped the National Parks on the Air (NPOTA) winner snag many, many QSOs. 5 Mhz you would have an end fed wire antenna that is 267 ft. To make a fair receive antenna, cut the length in half to 5 meters, and that is how long a wire antenna has to be to receive the 10 meter ham band. Coil the coax into three turns with the marks aligned. I did not have enough wire in my junk box to create a 68 uH coil. For details, please visit our Products section. antenna consisted of a 32" (-81cm) stainless steel whip and a motorised loading coil section that was about 16" (-40cm) closed. Authentic Genuine Nagoya UT-72 Super Loading Coil 19-Inch Magnetic Mount VHF/UHF (144/430Mhz) Antenna PL-259 Dual Electronics MAW40 Universal Soft Wire Flexible. shortened the antenna can be a nightmare to. The baluns were designed as current baluns according to Sevick ("Transmission Line Transformers", 4th ed, Jerry Sevick, W2FMI, Noble Publishing). (Possible subs include: J308-310, U310, 2N4857-4860. The truth is, an antenna loading coil has an inductive reactance value, which cancels the capacitive reactance value, that a shorter than quarter-wave antenna exhibits. It works fairly well and greatly improved reception of a weak station 130 miles away. An antenna wire that is an inch too short will leave a large section of antenna wire unsupported, whereas one that is an inch or two longer than needed to reach the last support is easily tolerated, and may even be an advantage in subsequent tuning. The first noticeable difference is in the length of the antenna whip. 6 Single Wire Top Loading 10 antenna, by using a loading coil which is effectivaly in series for the elements was chosen to form as long a current path from. Homemade coil for antenna tuner. Some transceivers already have an internal antenna tuner. Attach one end of this coil to the antenna. ***AIR COIL with base. Shiny streamer marks on the surface of the plastic show where the intense electric field has caused corona or "streamers". - So they act as loading coils on lower bands • A 3-band trap dipole fits in less space than a fan dipole - 20/15/10 is about 26-27 ft (20M dipole = 33 ft) • Traps add some loss - Typically 1-2 dB - A lossy antenna is better than no antenna • Traps reduce the SWR bandwidth - Trim lengths carefully and use a tuner!. The loading coil and variometer consists of two windings wound on a 110mm diameter stormwater pipe. The base of each whip features a standard ⅜ - 24 mounting stud for installation on mobile or fixed antenna mounts like MFJ's lip mounts, magnet mounts, tripods and dipole mounts. The proportional height of the coil can be adjusted by changing lengths of the mast and rod while keeping their sum constant. Homemade HF antennas for mobile operation - Build an Outbacker style mobile antenna 'Shorty' Dipole for 14 MHz Antenna Magic - Devoted to light weight wire beams and quad antennas N4UJW ANTENNA DESIGN LAB - The best HAMS have a good antenna The Stake Stick Vertical - Portable antenna 80 & 40 M Vertical Tiny ATUs for the Trail. Here is how I managed to get pretty decent results with a homemade antenna. The loading coil/choke consists of 55 turns of 24AWG enamel wire on a piece of 3/4″ PVC pipe. Try to get as much wire in the air. The loading coil is a passive device and does not receive any external power. Wound at 3. The max length the FCC allows is 3 meters or 9. A loading coil or load coil is an inductor that is inserted into an electronic circuit to increase its inductance. The N-channel JFET shown is a J309 but other similar parts may be substituted. 73 and good crystal DX. Long Wire Un-Resonant Antenna. The EconOceanic design provides for two antenna connections: one 1/8-inch phone jack and a spring-loaded clip (originally intended for fastening hi-fi speaker cables). Improvising an End Fed Wire • Think about where most current will be – Current must be zero at an open circuit – Current will be max λ/4 (and 3λ/4) from an open circuit (low impedance, easier to match) • Could be closer if loading coils, capacitance – A high current point high and in the clear usually makes the antenna more efficient. Holes in the coil form make it easy to clip onto the coil windings. Attaches to antenna body for storage. The bottom of the loading coil is 3/8" stud mount. The antenna as shown here can handle up to 1000 watts input. The coax is tapped onto the coil at the 50 ohm location. The G3JVL 6M ground plane vertical is a compact antenna that is ideal for portable operations. Given the small size of my garden even a long wire contorted with lots of bends wouldn't easily fit. Dipole antenna VS. The coil was mounted on nylon screws and coils were made rigid with epoxy. Also see Appendix C at the bottom of this page for many examples of. It is a full sized 40m dipole, and the 80m loaded dipole is cut so that the center part is a 20m dipole. Also called flexible grommets, flexible bushings etc. (5) 50/50 loading: This is where half the antenna is loading coil and the other half is either straight wire or a mast. Umbrella - Very large wire transmitting antennas used on VLF bands. 67) electrical building wire was used. Always cut your antenna lengths a bit long. The first quick fix you can make is to effectively add additional length to your antenna by putting a large coil of wire between the antenna and the set. Within this physical description there are two distinct antenna types. One side of the antenna (wire) goes up the 11 meter fiberglass pole and from the top towards the house. Some months ago I started to play with arduino's RF communication (low-cost arduinos' RF communication) the next step of the project is to make it long-range. I would still appreciate some. A fixed length wire dipole is usually mounted above ground using masts. I used your formula and wound the coil directly onto a cut-down Shakespeare VHF marine antenna cut to 30 inches and machined a stainless plug for the top with a hole and setscrew for a 1/8″ whip. The center loaded wire I had for 160 meters required to much maintenance, so I did not repair it after it blew down the last time. Attaches to antenna body for storage. On another page, I described a loading coil that I built for a center-loaded 160 meter vertical. band because the losses are low, but this generally limits the use of the antenna to one band. 0MHz, so a tapped base-loading coil is then used to tune it across the amateur band. I like to use a home made current choke to keep RF from coming back on the feedline. Basically, the electricity travels from the transformer through the antenna, then out into the "air". • If trees are used, leave some slack in the antenna so that swaying of the branches does not snap the wire • The support should be tall enough that the dipole is at least 1/2 wavelength about the surrounding terrain ( /2 =492/f). The voltage separation may be 300kV but if the coil is made of 0. (2) The "bandwidth" of the antenna will be reduced. Figure 2: Adding a loading coil to the antenna. <> ①If the CP8040 is located on the roof of a house or top of a building, look around the roof to see if there are any obstacles such as an electronic wire or TV antenna. Here is a photograph of a loading coil:. The simplest multiband antenna is a random length of #12 or #14 wire. The length of the wire beyond the coil has to be adjusted for the desired portion of the 80 mtr band (or of the 40 mtr band, if making the 40-10 antenna) and the local environment. 5 inches apart. [wire, bucket, cable tie, ring cable terminals] Step 5. For details, please visit our Products section. Discussion a 20 meter long wire into a 40 meter long wire. 500 MHz up to 6 meters. But not break. A lower radiating coil is wound over the antenna wire between the top loading coil and the lower, mounting end of the antenna, and is capacitively coupled to the. The formula for calculating the approximate length of a quarter-wave vertical antenna is:. T-antennas are widely used as transmitting antennas for amateur radio stations, long wave and medium wave broadcasting stations. It reviews basic electromagnetic theories on antenna coils, a procedure for coil design,. You can calculate the amount of wire of width W needed to make a coil of radius R and length L by using the formula 2?R x (L/W). 3 metres long which is an ideal size for hand-baggage on aircraft. A single long wire antenna is not a very good design, but is all that is really practical for most R/C**. A T-antenna, T-aerial, flat-top antenna, or top-hat antenna is a vertically polarised simple wire radio antenna  used in the VLF, LF, MF and shortwave bands. The antenna is resonate on both bands and does not require an antenna tuner. Notes: The feedpoint is the end of the antenna that is attached to the receiver. The coil & the whip are one piece. It helps to pre-tune it with an antenna analyzer such as the MFJ-259B which I modified to work down to a little below 470 kHz. A Return Loss of 25 dB or more is well within reach of this antenna topology. In the example shown in the sketch, 50-50 indicates that the load is attached to the mast and the 50+50 has the load attached to the coax. Starting at the top “see photo right side” a Delrin lower coil support with. QRPGuys Portable 80/60m Vertical Antenna – $20 Expanding on our experience of using the readily available $10 eBay telescoping 17′ fiberglass fishing poles for a vertical support in the Tri-band Vertical Antenna, we are offering a portable 80/60m, center loaded, 15′ long vertical antenna. A transmitting and receiving antenna, e. Also see Appendix C at the bottom of this page for many examples of. Wire Length. The loading coils isolate the extra wire. 5, and Hi-Q-3 antennas. It is possible to put up loaded antenna for the 2200m amateur radio (HAM) band in a suburban backyard. Should be mounted as high as possible in the antenna mast to increase the current radiating portion of the whip. An easy way to make such a balun is to paint the outside of the coax with conductive paint, then to connect this paint to the braid. The tripod construction remains the same, using legs approximately 4 feet long, but the mast has been shortened. 0MHz, so a tapped base-loading coil is then used to tune it across the amateur band. By Richard Q. Antennas capture wavelengths in the air and convert them into audio and visual signals that you can watch on TV or listen to on the radio. There will be less voltage when you have a poorer ground and less voltage if the antenna is just a small wire instead of a mast. In other words, a longer length similar to that of the 102” whip is achieved on a shorter CB antenna by wrapping the antenna wire close together, forming a coil. This is because the transmitter works best with a 50 Ohm load on the antenna terminal. So far received 119. Will use the Coax Trap Design calculator software to design the 20 meter Coax Trap (See Reference Links). Try this: buy a spark plug and connect your long wire antenna to the "hot" terminal. ***AIR COIL with base. Copper house wire prices have skyrocketed in the recent months. On 160 meters, it is only 0. The wire used here is 7 strands of 7 strands, which makes it very flexible. Here is a photograph of a loading coil:. This is simply a length of wire run from the house to a convienient support. NOTE Honda uses a dual. Clearly, there are (at least) two ways to tune a Slinky dipole:. The impedance of a long wire antenna varies as the frequency is changed, but the normally accepted values are from a few hundred to a few thousand ohms depending on length, height, ground conditions and. Very Short NVIS 160-meter Dipole Larry Nelson - K5IJB. This is an idea I have wanted to try for some time. remove a section or two, use more or fewer sections, decrease or increase sections lengths, or place the loading coil in different positions. To construct the balun, mark RG-6 coax with tape at two spots 27″ apart (26″ for RG-59). The Wilson 1000’s higher gain performance is a result of several new design developments that bring to you the most powerful CB base loaded antenna available in its price range A large portion of the power that goes into a typical base loaded CB antenna is lost as heat in the coil and as dielectric heat loss in the plastic inside the coil form. 2 MHz with a SWR of 1. Trimming for 7. The principle of operation is substitute the wire or rod antenna element inductance value with the same coil wound inductor, this coil equating to the same inductance as the inductive value of the Yagi beam antenna elements, from the reflector through to the di-pole and 5 director elements. We often find inexperienced builders of 5/8th wl antennas think the "loading coil" needs to contain 1/8th wavelength of wire in order to make the 5/8th wave antenna a "3/4wl resonant antenna". A receiver's antenna may be that simple, but that is not quite true for a transmitter antenna. This gave me the opportunity to check on how the inductor stood up against over a dozen northern Ohio years. realizable goal for a Novice station using one antenna on four bands is to work all states and Canadian provinces, along with some casual DX (Europe and South. Homemade HF loading coil for short antennas. 3 — The braid of the coaxial cable is used to form the trap coil; it is soldered to the no. Power can be fed to the wire on practically any frequency by one or the other of the methods shown i n Fig 1. And don't hesitate to make changes based on hardware availability. Are you looking for an antenna for your HF station let’s talk about antenna types and terminology and sorting through the types of HF antennas on the market and the sometimes obscure terminology used most of these antenna types are available from a multitude of manufacturers and some are easy to make yourself we’ll take […]. 2 and 3 show a trap made for use Fig. The loading coil is to be wound on the 45 mm tube with AWG 26 wire (51 turns) or similar. Where weight is critical, 40 gauge plastic-coated copper wire. I almost bought one of these for around £30, but then decided to make one. Consists of a central mast radiator tower attached at the top to multiple wires extending out radially from the mast to ground, like a tent or umbrella, insulated at the ends. I used your formula and wound the coil directly onto a cut-down Shakespeare VHF marine antenna cut to 30 inches and machined a stainless plug for the top with a hole and setscrew for a 1/8″ whip. Hence, antenna impedance is a simple concept. To Avoid the Loading Effect: Induce the test signal into the antenna 1. The top loading consists of two, 100′ parallel wires of standard #14 hard drawn antenna wire – that stuff that wants to coil back up and kink! You know what we’re talking about here! OK, originally I used a single strand, directly above the parallel radials described above. 2 shows how to add a loading inductor to the antenna. " Antennas for Wi-Fi are no exception. Then, feed the antenna wire for the 40m part (ca. Many truckers use two co-phased Antennas mounted on their mirrors. Feed the antenna at the bottom of the base load coil. One of the six plastic spacer arms was cut from a larger piece of plastic. Solder a long wire to the ground of the transformer (noted above) and attach that wire to a grounded conductor (like the ground on the average wall socket). It is very lightweight and close to invisible when up in the air. The coil will need to be cut to resonate, and can be fine tuned by stretching the length of the coil. Example: N6HH has 2. I did not have enough wire in my junk box to create a 68 uH coil. Where only single-band operation is wanted, the λ/2 antenna fed with untuned line is one of the most popular systems on the 3. Make the diameter of the coil equal to twice its length. Here’s an award-winning, easy-to-homebrew, multi-band portable vertical antenna designed by long-time antenna aficionado James Bennett, KA5DVS. These coils are just a coil of wire. The radiation pattern of a T-antenna. Wire Length. It is very small and consequently very inefficient but nevertheless the slow CW or QRSS signals from the beacon reach 100miles radius most of the time and this range extends after dusk. Putting it all together: Feed the loading coil over the squid pole and tape the wire to the top of the pole. How to Build Antennas. It has been purposely reduced in length compared to a full sized 80m dipole by the insertion of a 70uH loading coil. Will use the Coax Trap Design calculator software to design the 20 meter Coax Trap (See Reference Links). A typical short antenna. The coil of Litz wire on this rod measures 250uH and it is used as an auxiliary antenna input coil. You may use 12 or 14 AWG wire. Antenna Types by Coil. The linear loaded part of each element is formed from a length of 450 ohm ladder line about 15 feet in length. Below is the SWR plot for the initial ‘retuned’ antenna that uses a series L-C to get back the resonance on 160 meters. It's just a coil. Add Wire: Use conductive eyebolt at antenna top to install wires for an inverted "L" or a "T" to enhance low frequency coverage. The vertical wire extending from the coil to a support line (weed eater line) tied from a tower to a tree. 500 MHz up to 6 meters. proper feed can be an effective antenna. • Loading changes antenna characteristics – Feed Impedance, Gain and Angle of Radiation – • No reduction in the requirements for – height above earth – ground/radial systems • With expedient application of the loading the efficiency of the system can be kept high – Apply ‘end’ loading first – Apply inductive loading in the. It's a wire-wound antenna and features a custom-blended glass fiber reinforced shaft to create a good balance of flexibility and strength. 5m high; in the base is isolator PVC pipe with diameter of 50mm and 0. Not the best for the job but cheap if you buy 14/2 with ground house wire and strip the wires from the sheath. 8) around the loading coil pipe and the 1 1/2" PVC pipe as illustrated. The loading coils isolate the extra wire. Some early coil designs, still being sold today use coil construction and. And here are the elements for the antenna for the above SWR plot. Crane Twin Coil Ferrite Antenna Distributed by C. In August of 2010, I finally lowered that antenna to the ground, in preparation for replacing it with a new vertical. Making First Loading Coils for FM Vertical Antenna, operating fequency on 88MHz, this is a simple prosuction suitable for amateur radio. You can get Ultra Flexible Silicone insulated stranded wire at Hobby King. The next step in my pursuit of 630 meter Shangri-la, also known as Nirvana, was to build a loading coil and variometer to match my existing low band antenna structure to the new band. Since each leg was originally 40 feet long, the loading coils were placed at the 28-foot position. One side of the antenna (wire) goes up the 11 meter fiberglass pole and from the top towards the house. The loading coils of a short dipole must therefore be positioned away from the ends but still be closer to the ends than to the center feed point. 8) around the loading coil pipe and the 1 1/2" PVC pipe as illustrated. Pat MacKenzie **The new Plantraco 900 mhz system uses a dipole, but at 900 mhz it is very short. A Broadband 80/160 Meter Dipole An easy to build single wire antenna for 160 and 80 meters with a better than 2 to 1 swr across the 80 meter band. First, a long wire antenna is an antenna that is some multiple of wave lenghts at a specific design frequency. Keep the "excess" wire that will be in the balun to a minimum. The ends of the wire are then soldered or fastened, e. The 480XL coil is designed for use on tall vehicles such as 18 wheelers which do not allow the use of long whips and the overall height of the antenna. 14m long and 40mm in diameter and consists of nine telescoping sections (see text). 15, 12 or 10 meter bands, the loading coil is bypassed and with a short jumper across the coil terminals the antenna operates as a full sized unloaded half-wave (λ/2) dipole. For dipoles, use two whips with the MFJ-347 dipole mount. or the amount of wire wound on a loading coil. Choke Coil, Air Coil, Copper Coil manufacturer / supplier in China, offering Wholesale Copper Wire Coil Electric Inductive Coil, MTA-400 Coil Winding Machine Magnetic Tensioner with Cylinder, Discount Price Coil Winding Machinery Textile Magnetic Tensioner and so on. Make your own loading coils for antenna projects using Caterpillar Grommet. Typical antenna lengths for the amateur bands from 160 - 10m, both when using insulators or nylon rope, are shown in Table 3. Starting at the top “see photo right side” a Delrin lower coil support with. The baluns were designed as current baluns according to Sevick ("Transmission Line Transformers", 4th ed, Jerry Sevick, W2FMI, Noble Publishing). This feature is not available right now. Then it may be said that the coil has lengthened the antenna to achieve an electrical length of 2. The loading coil is designed as a variable inductor, with a three-legged chariot that travels up and down inside the coil, with grooved brass wheels running on the coil turns, and driven by a slotted rotor tube. The overall length of the slope wire is only 60 feet long. ) To calculate the length of a full-size dipole, use the Dipole Antenna Length Calculator. Should be mounted as high as possible in the antenna mast to increase the current radiating portion of the whip. The top part measured to be about 77uH, the bottom section measured to be about 80uH and the rotating coil was measured to be about 12uH. Some of the things I wanted to find out: Was the 1/8 wave length of the wire portion something magical, or could any length be used as long as the loading coil was correct?. The bottom end of the whip is connected to the radio receiver or transmitter. This loading inductor is near the bottom of a 43-foot tall vertical. Opinion 1: When part of a wire antenna is replaced with an inductive loading coil, the loading coil does not supply any of the missing degrees. Many truckers use two co-phased Antennas mounted on their mirrors. The efficiency of the voltage transfer can be increased significantly with high Q circuits. Homemade coil for antenna tuner. It's bank wound using 2 layers of 5x36x44 Litz wire. Aluminum wire is not expensive, but it is the least desirable wire for antenna use. SPECIAL NOTICE INSTALLATION &TUNING NOTES. They're a little long at about 1 1/4" long, but they work suitably. The 160-meter loading coils (Hy Power LC1682) are placed at the 70% point following the design by Hy Power for their 82-foot horizontal 160-meter antenna. On 160 meters, it is only 0. It runs up the front of the roof on the left as you face the house, then runs across the roof along the ridge vent (plastic construction), then down the back of the roof to the eaves at an angle. 005 S/m, Er=13). Use two plastic wire ties (ref. In the real world — where you build your antennas — the actual impedance of your wire antennas will depend on several variables. In two words, fabulous and exhilarating. 20, 2002 CODE OF FEDERAL REGULATIONS 10 Parts 200 to 499 Revised as of January 1, 2003 Energy Containing a codification of documents of general applicability and future effect As of January 1, 2003 With Ancillaries. shortened the antenna can be a nightmare to. I have used it with many radios from portables to large table tops…. It is a long antenna, but this is necessary if you want something that will work reasonably on the 80m band. Strung about 4 feet above ground over its 150 foot length, the antenna radiates best in the direction(s) the wire is running, away from the radio. Don't connect this circuit to a long wire antenna unless you are curious to hear what radio chaos sounds like. This antenna was the mark 3, the previous two 17. in them i. The circuitry is similar in complexity to a simple one-transistor radio but the performance is far superior. This was created as a fun project to demonstrate how to enjoy operating HF in the field with a home-made portable antenna without spending a ton of money. Once it proves to be stable the clip will be removed and the wire soldered right to the coil. Wind the coils counting one turn each time the wire passes the starting point. The loading coil is designed as a variable inductor, with a three-legged chariot that travels up and down inside the coil, with grooved brass wheels running on the coil turns, and driven by a slotted rotor tube. The total length of the wire is 88 feet. Antenna Loading Coil Calculation The calculation method is taken from a BASIC program which I got many years ago from OA4/KA2OIG who is hereby gratefully acknowledged. For dipoles, use two whips with the MFJ-347 dipole mount. Since each leg was originally 40 feet long, the loading coils were placed at the 28-foot position. Strung about 4 feet above ground over its 150 foot length, the antenna radiates best in the direction(s) the wire is running, away from the radio. 9) oriented with the tapped end of the coil down. Winter HF Antenna System. Copper house wire prices have skyrocketed in the recent months. The other side goes to the center of a coax connector on the MFJ panel. (Into a dummmy load. 3:1) on 80m and 40m, and below 3:1 on 20, 15 and 10m. It's just a coil. There is a shunt coil at the feedpoint that matches the very low impedance of the antenna on the 80 metre band to 50 ohms, and also provides a path for DC grounding of the vertical radiator elements and static bleed off. I had not used this clip for very long, but already there were signs of stress, shown below: The top part of the clip is bending and cannot take any force without further yielding. If your antenna is mounted outdoors, you should disconnect it whenever there is any chance of lightning in your vicinity. The tripod construction remains the same, using legs approximately 4 feet long, but the mast has been shortened. PAC-12 Antenna by KA5DVS. Long Center-Fed Wire Antenna. It is a full size antenna on 40 meters and a shortened 80 meter antenna. Building the Loading Coil For operation on the 20, 30 and 40meter bands, a loading coil must be added to the antenna. Cut four lengths of wire each 6. The system as described uses our BTC30 Tesla coil generator to energize the multi-wave antenna emitter. The coil system easily installs between the antenna’s end cap and the current antenna wire system. The imaginary part of the impedance represents power that is stored in the near field of the antenna. Loading coils for a 131 foot long 160 meter antenna. It has been quite a while since I studied antenna systems, but IIRC the long wire is not very critical. I've also made coils from #14 solid copper wire, wound around drill bits or broom handles to form them to a shape. I did not have enough wire in my junk box to create a 68 uH coil. Unlike the Firestik FS or Firefly antennas, the KW does NOT have a tunable tip. The horizontal wire is connected via a Plexiglas insulator with the rest of the wire of the former 160m antenna. What is critical is the space around the coil part and the open circuit end must be free from metallic objects like wires or the sides of a metal box, or the coil detunes and becomes an extremely inefficent antenna. The coil is so lossy (due to a long length of thin wire) that it heats up, and with if the adjustable whip is too far low in the middle of the coil, it heats uppainfully. This loading inductor is near the bottom of a 43-foot tall vertical. The 480 XL coil is the same diameter as the 480 coil but is 11 inches long and has 66 turns of 12 ga wire. enamel wire. One side of the antenna goes directly to a ground stake, for lightning protection. CB antennas can generally be grouped into three categories by load position. Authentic Genuine Nagoya UT-72 Super Loading Coil 19-Inch Magnetic Mount VHF/UHF (144/430Mhz) Antenna PL-259 Dual Electronics MAW40 Universal Soft Wire Flexible. This is simply a length of wire run from the house to a convienient support. Attach one end of this coil to the antenna. Adapts import and domestic vehicles with separate turn and stop lights (3-Wire System) to standard trailer tail light wiring (2-Wire System) stop/turn light: 2. Loading coil for vertical antenna keyword after analyzing the system lists the list of keywords related and the list of websites with related content, in addition you can see which keywords most interested customers on the this website. Consists of a central mast radiator tower attached at the top to multiple wires extending out radially from the mast to ground, like a tent or umbrella, insulated at the ends. A loading coil and variometer combo for 630 meters (and maybe 1700 meters too!) A Few Simple CW Transmitters for 630 Meters. This suggests that this Slinky dipole appears to be 20% longer than a same-size wire dipole. Magnet wire is typically sold by weight, so it’s important to know the required wire weight. It's a great HF antenna for the ham radio operator with a smaller backyard! The. What is critical is the space around the coil part and the open circuit end must be free from metallic objects like wires or the sides of a metal box, or the coil detunes and becomes an extremely inefficent antenna. the loading coil is used for these bands, on 15, 12, 10 and 6 you bypass the loading coil and must use a tuner. For each coil I glued two T50-2 cores together and wound 25 turns of #24 ga. 50 Ohm coax feed, rated for full legal power. The dashed lines represent bare wire radials and the solid lines insulated wire radials. HF'Wire'Antenna' • Polariza(on* • Impedance* • Long*Wire* • Loop* • Windom* • Ver(cal* • Antenna*Tuners* • Dipoles*. Each coil was made from a length of wire about 1/4 wavelength long. A vertical seemed the obvious answer, a naturally low-angle radiator. The outer coil is tapped to achieve resonance with the inner coil rotated for maximum inductance (about 350 uH in this case), which ensures the lowest loss in the coil. Any practical antenna is going to be electrically short at 136kHz. I used the MFJ 259 b meter to check inductances and found a coil in. It is a long antenna, but this is necessary if you want something that will work reasonably on the 80m band. Loading coils for a 131 foot long 160 meter antenna. Where weight is critical, 40 gauge plastic-coated copper wire. 5 KW -- the coil does not get warm at all (large diameter wire helps) and the system works very well despite the relatively low efficiency due to the shortened antenna, coil and ground losses. Last month I detailed a modification for the MFJ 259B antenna analyzer to extend the range to the 470kc region. Fiberglass 80 meter Vertical - Revised: 2015-11-06 One antenna in use at K0MPH is a fiberglass 80 meter vertical. Where weight is critical, 40 gauge plastic-coated copper wire. See page 63 for more MFJ mounts. For dipoles, use two whips with the MFJ-347 dipole mount. This is the original Firestik design, and a proven performer since 1975. 160 meter vertical antenna's base loading and matching unit The following pictures show what my 160M vertical antenna base loading and matching coil assembly looks like. Attach one end of this coil to the antenna. (Into a dummmy load. If you are installing it for permanent use, this is not important. Length is equal to 1/2 of the wavelength for the frequency of operation. Hence, antenna impedance is a simple concept. " Antennas for Wi-Fi are no exception. Copper house wire prices have skyrocketed in the recent months. I had problems with 20m and 6 meters, on both bands the TS-2000 was not able to tune. This is the Take it Along (TIA) portable antenna which helped the National Parks on the Air (NPOTA) winner snag many, many QSOs.