Loading Coil Antenna

Completed 28 turn coil. Here is the good news: practically any 50 ohm co-axial cable which you already use on HF 'will do' on MF. A standard dipole antenna is resonant if constructed with a length of one-half wavelength. I used the same dimensions as VK3CAE 6. ) The loading coil helps to resonate out some of the series capacity resulting in more antenna. L_TUNER * Calculate coil & capacitor values of an L-Network to match any pair of complex impedances. Amateur-radio-wiki. Elevation Polar Radiation Pattern 764 MHz. 8 shows a simple vertical ground-plane antenna which connects directly to 50 ohm coaxial cable without a loading coil or matching network. Buddipole Coil Set. Controls the amount of shunt capacitance in the antenna circuit. Shiny streamer marks on the surface of the plastic show where the intense electric field has caused corona or "streamers". The material of the antenna is grass fiber fishing rod. This coil is needed to increase the antenna electrical length by 1/8th wavelength so that it becomes resonant at 3/4 wavelength and the feed impedance is a low resistive value. The beauty of these antennas is that you can operate a full quarter wave on 6, 10, 12, 15, 17 and 20-meters WITHOUT a loading coil! Just be sure that your mobile operation takes wind-loading, trees, and overpass-height into account. By judicious. On the negative side, raising the inductor reduces the capacitance to ground, with the result that more turns are required on the coil to resonate the. Now touch the wire to each successive tap, moving downward along the taps (including the bottom coil end wire) until you find the tap that gives the highest. These are more formally known as trucker antennas, and truckers actually love them. The antenna is Currently Pre Tuned for 80meters Via an Antenna ANALYZER. Model a coil in any software, and look at current. The ground-system only consists of the water piping of the house. An antenna loading coil is an inductor placed in series with an antenna element in order to lower the antenna’s resonant frequency; A standard dipole antenna is resonant if constructed with a length of one-half wavelength. Adding to your cart. The coil was held in place by drilling two holes in the former about 30mm apart and passing the antenna wire through them from the inside. The loading coils were measured (12. The coil provides a match only and for the most part is not the primary radiating part of the antenna the whip or steel rod is. More than a simple "flagpole", this complete antenna system includes adjustable base-loading coil, Guanella balun, and counterpoise. 1 ohm represents the resistance of a copper wire 0. This time, I got a recommendation for a base-loaded vertical antenna. About Make Your Own Loading Coils The resource is currently listed in dxzone. You can use the same fiberglass pole arrangement you have for the Tri-band Vertical. Diamond® Antennas are sold through authorized dealers. "screwdriver") antennas. Those capacity hats are vulnerable when working on the antenna, so there had better be some performance benefit! Loading coils must be high Q to keep loss low in a yagi, which means large, and large means increased wind and ice loading, and risk of breakage. The way the coil is connected is standard for bottom loading - in series between the. There are actually two coils of wire wound around the ferrite rod. Model an antenna with EZnec, and look at the load. More designs can be found by Googling “80m loaded dipole. With a maximum height of 5 1/2 feet the antenna can be quickly removed from its mounting position for quick storage. ) Enter a distance between 0 and 250 feet that is less than half the total antenna height. Canadian owned and operated since 1999. I have given much consideration to the coils used, and to their placement in the loaded antenna. Yes the ham and 27 MHz ones were color coded. Radio antenna. 99 You Save: $3. • HVC14; 20m. More designs can be found by Googling “80m loaded dipole. high; used with art-13 transmitter. The term is also used for inductors in antennas, or between the antenna and. The vast majority of radiation from an antenna is from the portion of the antenna where the current is highest. • HVC21; 15m. It is designed to be used with a 6m fiberglass mast from lambdahalbe. Wire Antenna Calculator. Johnson INDUCTOR antenna loading coil 232-124. At about 14m, there is an elevated 1 mH basket-weaver coil. For top performance mast should be at least 3 feet long. See full list on hamradiosecrets. Wilson 1000 Coil w/Mast Screws #880-900100-B **B/O (6312) Wilson 1000 Coil w/Mast & Set Screws *Replacement Base Load Coil For Wilson 1000 Magnet Mount, Trunk Mount and Roof Mount Cb Antennas. The base loaded matching network. antenna, has a whip radiator connected to a loading coil, both of which are supported above a ground plane by a mounting structure. As with our other wire antennas, the user supplies the 15′ of 20-22awg wire for the driven element and four 10′ radial wires. More than a simple "flagpole", this complete antenna system includes adjustable base-loading coil, Guanella balun, and counterpoise. It's anecdotal, but the antenna seemed to be working fine. Resources listed under Antenna Coils category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. Here I test the rods and give you my impression of their performance. An HF mobile antenna loading coil should have a high ratio of reactance to resistance to minimize losses. The coil windings are inside the sturdy fiberglass tube, which Gary molds around the loading coil. The length of the loading coil wire was determined by the physical length of λ/8 at 146. The coil was held in place by drilling two holes in the former about 30mm apart and passing the antenna wire through them from the inside. NEC lets us model reactive loads. Antenna: The antenna is connected directly across the loading capacitor. ) newsgroup about whether or not modeling a short, loaded antenna using a lumped load model (inductor) is or is not a fair representation of the same antenna using a physical ("distributed") coil. 25 wavelength antenna without any coil. The DS1 Antenna is a small, portable, vertical antenna system for 40m thru 10m. Provision needs to be made to adjust the coil position. Linear loading has similar efficiency challenges, and with greater vulnerability to ice. (4) Continuous loading: At electrical lengths of 1/8 wave or greater, this is may be the most efficient way to shorten an antenna. 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. Antenna Loading Coil Calculation The calculation method is taken from a BASIC program by OA4/KA2OIG who is hereby acknowledged. Download Instruction Manual. Antenna 5, using a wire flattop of intermediate length, could reduce loading-coil requirements to a range of permissible loss, with space requirements being the trade-off. This program uses different formulae for 2, 3 or multi-element designs and includes element tapering Verticals covers all the common types with a coil calculator built in for the antennas that require them. Radio antenna. A loading coil for the antennas of the type adapted for use in the citizen frequency band and mountable at the roof, trunk lip or rain gutter of automobiles, the device featuring a tap lead-out mechanism designed to allow tap lead-out from the loading coil with no need of soldering the lead-out wire to the coil wire and to also allow easy connection to the coaxial connector unit. ) The loading coil helps to resonate out some of the series capacity resulting in more antenna. Use a self supporting air-wound coil instead (like the Butternut vertical antennas. Power is fed directly to antenna with a single 52 ohm coax line. On the negative side, raising the inductor reduces the capacitance to ground, with the result that more turns are required on the coil to resonate the. This entry was posted in Amateur Radio, Equipment and tagged amateur radio, coax, common mode currents, lmr195, loading coil, Ugly Balun, vertical antenna, VNApro. Bugcatchers, single coils with no shorting, spider mounts for multiple coils are very efficient. The coils use the 10' 4" sections of wire that were prepared previously to wind coils with 51 turns. If you’d want resonance on 15 and 30m, you only need a 15m or so long wire that will act as a full wave on 15m and as half a wave on 30m. the antenna can be matched to coax by using loading coils • For best results, the coils are placed in the middle of each leg of the dipole • Loading coils can introduce additional loss of 1 dB or more • For dipoles longer than /3 the antenna can be matched to coax by using linear loading. Wire Antenna Calculator. Loaded antennas Antenna Length and Loading Coil In low-frequency applications, it may not be practical to. I modeled the antenna using 4nec2 to get the dimensions about right and the loading inductance needed for both 160m and 80m. For instance, a transverter, QRP transceiver, and a simple load coil and transformer match assembly are all that is usually needed to utilize a new or re-purposed wire antenna. Now let me stop for a second and mention that I am painting with a very broad brush. The calculator below can possibly help you with your design. These are more formally known as trucker antennas, and truckers actually love them. This means that it has to be retuned more frequently than an antenna that doesn’t need a loading coil. 051 wavelength long. This Tram Oil-Filled Coil CB Antenna is very heavy-duty with great field strength. Compatible with automobiles, trucks, vans, motorcycles and ATV in a single antenna configuration when metallic ground plate is available. The total antenna mast ,loading coil and top hat can be lifted with one hand. Removable coil for safe storage & garage entrance Weather Cap included to protect mount when coil is removed 2 year warranty Wilson 5000 antennas for their size, perform very well! Wilson and us are the few out there that actually make their antennas with silver plated coils. Plastic end supports are used to eliminate the excessive RF losses that are common to many other. Coil (2uH) at 3/4 the antenna length from feed-point: frequency=25. Antenna? Transformer is a 1:49 or 1:64 UnUn (not 1:4 or 1:9 used on random wire antennas) 50 Ohm Coax from transformer to station Multi-Band (works on all harmonics) Deploy it horizontal, sloping, inverted-L, inverted-V Commercial example: MyAntennas EFHW-8010-2K Pass it around (I want it back!). 4415: 2112 116th Ave NE Suite 1-5 : [email protected] Designed for use with all 3/8 24 tpi, Antenna fittings & Mounts. 5 turn per 25mm) Number of turns depends on the length of the antenna. Step 2: Touch the other probe to the metallic threads at the end of the antenna. I would wind the coil for 15 + uh and use an antenna analyzer to check the match. A loading coil of approximately 2. The stock version handles 1-kw of power and can be upgraded to 5-kw plus if needed. On the negative side, raising the inductor reduces the capacitance to ground, with the result that more turns are required on the coil to resonate the. Recommended for the MFJ-63, LOADING COIL, 40/80M FOR 1644. Every Day new 3D Models from all over the World. tive reactance with loading coils some-where in the antenna structure. Inductors are 32, 16, 8, 4. Use 1/4-compression-to-1/8NPT male and female brass adapters for the coil support end pieces. Power limit of 1. 2m used after the loading coil. The GS3 loading coil is a real work of art. These are more formally known as trucker antennas, and truckers actually love them. The antenna is strong enough to withstand almost any impact. 04438 antenna. Hua Wang, Kaushik Sengupta, in RF and Mm-Wave Power Generation in Silicon, 2016. 40 meter quarter wave vertical with loading coil. I suggest that if you're building a new coil, you should tap it like this:. Third, make a short flexible insulated wire, 18 or so inches, with an alligator clip attached to one end. Spring antenna custom design service, antenna shape customization, impedance matching design debugging, antenna design, built-in antenna, omnidirectional antenna, spring antenna, 433MHz antenna, 433M antenna, 433 antennae, 2. Can someone help me understand in practical terms what kind of performance difference one might expect between a shortened, loaded antenna vs a full length one? Thanks! 9 comments. Published in CML-47205 antenna loading coil. Contemporary antenna tuner circuits claim to be able to operate into an unbalanced load or a balanced load such as ladderline. There is a current at one end of the inductor, and it will produce a magnetic field. Wilson 1000 Coil w/Mast Screws #880-900100-B **B/O (6312) Wilson 1000 Coil w/Mast & Set Screws *Replacement Base Load Coil For Wilson 1000 Magnet Mount, Trunk Mount and Roof Mount Cb Antennas. The 1/4-compression ends of the adapters do a great job of securing the 1/4" diameter fiberglass rod as shown. Controls the amount of series inductance in the antenna circuit. You are running 1,000 watts to a 70% size dipole whose coils have a Q of 100. The loading coil on all "KW" antennas is easily accessable for precise SWR adjustments. This loading coil is used to resonating the vertical radiator into a frequency near the targeted frequency. The coils are wound with tinned solid copper wire that is embedded in. 6m above the base, and a whip section of 1. This means that it has to be retuned more frequently than an antenna that doesn't need a loading coil. x 24 thread mount just be sure to buy a heavy-duty one to keep this antenna firmly seated. The antenna is resonate on both bands and does not require an antenna tuner. 79 Mhz, ideal for DX. Notes on Modeling Short Inductively Loaded Antennas. The device is rated for 20W, has all stainless steel hardware for the antenna, loading coil, and radial connections. In layman terms that means we need fewer turns of the coil, when using a longer whip. The 1/4-compression ends of the adapters do a great job of securing the 1/4" diameter fiberglass rod as shown. Though this isn't nearly as efficient as using a regular 102" antenna, it allows for shorter and more practical CB antennas. Vertical antenna loading coil by SA2CLC - Thingiverse. “maintaining resonance” • Loading changes the current profile and therefore the characteristics of – Radiation Pattern •Gain •Angle of Radiation – Feed Impedance – Operational Bandwidth. Mobile Load Coil Antenna Spring B132S MODEL DESCRIPTION OVERALL HEIGHT TUNING B132S 132-525 MHz, Base Loaded 1/4 Wave Broadband, Chrome Finish 23" See Cutting Chart BB132S 132-525 MHz, Base Loaded 1/4 Wave Broadband, Black Finish 23" See Cutting Chart MODEL AND ORDERING INFORMATION MECHANICAL Height 23" (Also, see cutting chart) Diameter. For example, from the top of the antenna:. Wire Antenna Calculator. Indeed, as wrote Walter Maxwell, W2DU (sk), in his articles "Another Look At Reflections" about antennas, SWR and line losses appeared in QST magazine in 1973 (Part 2, Chapter Line losses, §27) : "Models having lowest SWR are wasting power in the loading coil, because of either a low value of coil Q or excessive distributed coil capacitance. Termination loss is 6dB. The largest coils are wound on stacked Amidon (Micrometals) T-157-2 carbonyl iron toroids. 5mm building wire. This means that it has to be retuned more frequently than an antenna that doesn’t need a loading coil. Will a loading coil have the same effect on a end-fed ½ wave (vertical) as it does on a ¼ wave vertical (ie allowing you to shorten the vertical radiating element)? My gut feeling is that it probably won’t work because an EFHW is already fed at a very high impedance (hence the need for the 49:1 transformer to feed it), so. The length of the loading coil wire was determined by the physical length of λ/8 at 146. Counteracting the effects of capacitance, they make line impedance approach the equivalence of pure resistance. Start by inserting the wire through one of the holes of the coil form leaving about 2". Enter a diameter between 0. The loads can have a resistive as well as a re-active component, as shown by the NEC-Win Plus load screen in Figure 2. Genuine Diamond Antenna accessory. Posted on May 23, 2020 May 23, 2020 Full size 1200 × 900 Post navigation. The end wires should be trimmed for resonance on the required part of the 80m band. A couple of radio amateurs have put some nice pictures on the web that result to be very instructive in explaining how to construct high-Q loading coils: Mark Peterse, PA3HMP came up with an elegant design for the trap coils of his wire dipole antennas, solely based on standard PVC tubing. The original javascript was created by Prof Jack Ponton from The University of Edinburgh. Each coil has 3 recessed channels which allow for nearly a hundred tapping options. A physically small loading coil simply inserts a series inductive reactance that cancels capacitive antenna reactance. I have mostly used the transmitter and that is actually fairly OK with just a simple 1/4 lambda antenna, but is open for improvementThe receiver however is a bit cra…. Coil loading is a required aspect of many lower HF antennas but is not by any means efficient. Genuine Diamond Antenna accessory. 67) electrical building wire was used. UPC: 646444820653. Like our SB1000, the Silver Bullet Platinum will tune 80 thru 10 meters, but the Platinum will handle 100 watts digital, 300 watts CW and 500 watts SSB. Loading coil calculations. These are all for 72 (75)MHz receivers. Any reputable antenna manufacturer will have coils that the current into and out of the loading coil ( the inductor ) should be close to equal. The original version had a single loading coil to tune an Edison 60W Zsquirrel cage lightbulb on 40M. The coils use the 10' 4" sections of wire that were prepared previously to wind coils with 51 turns. Barker & Williamson air wound inductors have been an industry standard since their introduction in 1932. The coil is the most recognizable form of an inductor. This tool is designed to calculate the inductance of a coil of wire given the number of turns, the loop diameter, wire diameter, and the permeability of the medium. Antenna loading coil: Everything You Need to Know. Warranty 2 Years. Diamond Antenna's HVC loading coils feature a brilliant-chrome finish. Adding to your cart. This calculator is designed to give the vertical length (height) of a particular antenna, for the frequency and wavelength chosen. A New 630m Loading Coil & Variometer. The threaded rod is lubricated with. 6 ohms, as measured. sciencewriter. the impedance of a /4 antenna is 36. Multi-coil continuous spiral loading, wire wound on segmented fiber tubing with insulated. How the antenna works as a multiple of half wave lengths on the higher bands: Loading Coil The 110µH loading coil is used on the version for 80m. Mobile Antenna 15M Loading Coil for HV7A $37. Spread the 5-turn hairpin coil to ¼ inch spacing (coil to coil) or until a satisfactory SWR is obtained. 80 (5 offers) - Buy CML-47205 Antenna Collins Wwii Ham Coil Radio Loading TCS-12 WW2. Hustler narrow coil design allow the antenna to. I'm looking at the QRPguys vertical 3 band antenna, for 40/30/20m, where they switch in 1 coil for 30m and 2 coils for 40m. The Nagoya UT-72 Super Loading Coil 19-Inch antenna is arguably the best magnetic mount mobile antenna for VHF/UHF applications. Loading coils need to be kept away from metals, and unused turns should be left open. The original version had a single loading coil to tune an Edison 60W Zsquirrel cage lightbulb on 40M. PDF | Shortened dipole antennas based on rectangular dielectric blocks play an important role in ultrahigh field magnetic resonance imaging (UHF-MRI) | Find, read and cite all the research you. thingiverse. The antenna provided in the first link looks similar to. Antenna Loading Coil, ATC, CJP-47282. Whenever anv sertical antenna is shortened from its full physical 1/4 wave length it is compromised in certain ways. When autocomplete results are available use up and down arrows to review and enter to select. Sign in to check out. Three coil assemblies were built before I was happy I was as close as I could get to a good match on. A high power, high performance antenna. This afternoon, I’ve been playing with an 8 meter fishing pole in the garden, clamped to a 3 meter aluminium pole with 2 x 10 meter elevated radials sloping from the feedpoint at 3 meters to fence height. 35" Stainless Steel Whip Base Loaded Coil 10 oz Magnet 15ft. The loading coil of the GS3 antenna. To achieve the required loading coil and due to some practical limitations, the maximum allowable diameter and length, C2 and l, respectively, of the coil were defined. The power is wasted as heat loss and not radiated as radio waves. Definition of Loading coil in the Definitions. Country: United States of America (USA). 30m x 95% = 1. Designing an AM radio ferrite rod antenna coil (also known as tank circuit) for a crystal radio project or any radio project is something GCSE students and hobbyists love rushing into with guesswork. The hermetically sealed stainless steel housing ensures long lasting communication throughout your team’s. Designing an AM radio ferrite rod antenna coil (also known as tank circuit) for a crystal radio project or any radio project is something GCSE students and hobbyists love rushing into with guesswork. 5/8 vertical antenna design. With coaxial mounted loading coils, this is not a problem, but this antenna has the loading coil mounted off-center from the mast. Spring antenna custom design service, antenna shape customization, impedance matching design debugging, antenna design, built-in antenna, omnidirectional antenna, spring antenna, 433MHz antenna, 433M antenna, 433 antennae, 2. There's got to be a tradeoff when you use an loading coil on a short antenna, but I'm not understanding what that tradeoff is. The estimated Antenna Factor is -1. (Enter "0" for a base loading coil. 0 MHz (Whip needs to be cut to 33. the antenna can be matched to coax by using loading coils • For best results, the coils are placed in the middle of each leg of the dipole • Loading coils can introduce additional loss of 1 dB or more • For dipoles longer than /3 the antenna can be matched to coax by using linear loading. The worst mistake I made was thinking matching coils were an exact science when the exact opposite is true - matching coils can be big or small, air coil or iron powder (but never ferrite) core, horizontal, vertical, wound around a toroid or any combination of these. As with our other wire antennas, the user supplies the 15′ of 20-22awg wire for the driven element and four 10′ radial wires. Position the solder lug end of the twinlead at the top edge of the pole's protective base. All you need to do is enter the desired resonant (center) frequency in the form below, then click "Calculate". The K7MEM website cited earlier also includes a good coil design program, the results of which are: D= 2-3/8" (2" PVC), N=26 closed-packed turns of #16 AWG enameled wire, resulting in a coil length of L = 1-7/16". Such a coil is obtained when the length of the loading coil is half the diameter, L/D = 0. 75 inches in diameter. I designed this antenna to withstand the harsh wind, salt, and lightning conditions of the south. Loading coil calculations. (Received October 21, 1964; revised December 12, 1964) In this paper, a method is presented by which the distribution of current on some structurally simple coil or multi turn loop antennas may be obtained. I hope that provides some additional information about making up 5/8th wave antennas. The Experiment: In this experiment were going make a Ham Radio 20 / 40 meter short coil loaded dipole antenna. For whips and verticals. and a 17ft antenna arm, with the coil at 0 distance from the feedpoint, I get an inductance of around 50uH ,. Here is montage of me making a loading coil for vertical antennas from scratch using the Ender 3 3d printer. The coil at left is 1 inch in diameter, has 9 turns, and wound with #14 Thermalese ® (enameled) wire. What I am using for LF antenna matching is a relatively small ferrite pot-core instead of big coupled air coils. Holding the short antenna wire lead coming from the transmitter antenna plug, touch it to the topmost loading coil tap (topmost tap, not the top end of the coil). Loading Coils (two per package): The coils packages come complete with instructions for wire lengths and coil placement. It's not a great SWR curve due to the loading coil but I achieved 1. Another design by KB0ZZ is a little longer, but resonates on both 40m and 80m. Note the meter reading. 40 meter quarter wave vertical with loading coil. Tram 717 Oil-Filled Coil CB Antenna, 6" Stainless Steel Shaft; 52" Tall; 1,500W; Heavy-duty, High-grade Copper Loading Coil Offers Greater Field Strength; 6dB Gain; Stainless Steel, 17-7 PH Tempered,. The worst mistake I made was thinking matching coils were an exact science when the exact opposite is true - matching coils can be big or small, air coil or iron powder (but never ferrite) core, horizontal, vertical, wound around a toroid or any combination of these. It is a plastic cylinder about 10cm high and 6cm. In layman's terms, it is like taking a 8ft whip, measuring off the desired antenna length, and wrapping the excess length into a coil. The coil provides a match only and for the most part is not the primary radiating part of the antenna the whip or steel rod is. Power limit of 1. Those capacity hats are vulnerable when working on the antenna, so there had better be some performance benefit! Loading coils must be high Q to keep loss low in a yagi, which means large, and large means increased wind and ice loading, and risk of breakage. These are used by installers to form protective bushings around the edges of holes cut into sheet metal, and come in strips that are cut to desired length then snapp ed into the hole to cover the raw edge. I found the Chameleon MIL Whip 2. They think, through wire length alone, the wire creates a low feed impedance by making the antenna three-quarters of a wave long electrically. Five eighths wavelength vertical antennas are often used on automobiles. Conclusion. Base loaded will require a lower inductance and more towards the top will require more inductance. The Antenna should be trimmed to length to establish the desired Frequency; A Marine VHF antenna is center tuned to 156. Yes, the liquid kind. At 10 metere, it is just 0. Published on April 9, 2016. The antenna cable was then threaded through the cleat and secured with a nylon tie-rap as shown in the image above. 25 wavelength with loading coil. Check out as guest. Making a Remotely Switched Load Coil Now that you have built a flagpole antenna and the yard is filled with 32 buried radial wires to make a ground system you are ready for a tuner or better to make your own matching system. Power limit of 1. Frequency Range 760-870 MHz VSWR < 2. This gave me the opportunity to check on how the inductor stood up against over a dozen northern Ohio years. The antenna can be erected in less than 5 minutes and works much better (about 10 dB) than the doublet which I tried to tune up on LF before. Genuine Diamond Antenna accessory. By judicious. Some coils are held together by clear epoxy ribs, others use scrap pieces of PC board and epoxy. I've been asked if Gary 104 has made any new videos?. Hustler narrow coil design allow the antenna to. 074-048 Variable Antenna Loading Capacitor, 3-Section, 15-520pf per section. A19880552000. 3G; 4 GHz Single Turn Double Helical Antenna; 4:1 balun; 4. Another option is a shortened dipole using loading coils. •Loading is the modification of a short antenna so it looks longer to the transmitter (often resonant). Antenna Loading Coil Calculation The calculation method is taken from a BASIC program by OA4/KA2OIG who is hereby acknowledged. by changing the spacing 1/8 inch you can change the frequency putting up tilt or down tilt in the antenna, the spread sheet can be used for any vhf. This antenna solves the problems of working "top-band" and eliminates the need for a tuner. Dipole antennas are normally ½ wave but I will show you how to build a dipole greater than a ½ wave and still keep it resonant to the 2. Loading coil calculations. com Home Mapsite Add Link. I designed this antenna to withstand the harsh wind, salt, and lightning conditions of the south. MR-73SJ Magnetic base type 2m/70cm antenna package has --/3. The bottom of the loading coil is 3/8" stud mount. How come? Well, the loading coil must always "trail" the antenna mast; that is, the coil must be directly behind the antenna mast when the vehicle is moving. For instance, a transverter, QRP transceiver, and a simple load coil and transformer match assembly are all that is usually needed to utilize a new or re-purposed wire antenna. It’s got a bottom loaded coil to get on 40 meters. It consist of 2 parts whip, one fixed and one collapsible on a certain height regarding the band, and a multi tap base loading coil. However, if we experiment with inserting the coil into higher locations in the vertical radiator, we find that the current distribution on the antenna. It is resonant on 20m without the added 40m coil, but requires a tuner for the other bands. R&L Electronics: Text Questions to 513-868-6399: 800-221-7735 Antenna Accessory. A small loading coil simply inserts a series inductive reactance that cancels capacitive antenna reactance. The third version, again used the Edison bulb with a multi-tap coil for multiband operation. The MP-1 is a universal antenna with 180cm length and max. 23m ( Panjang antenna). Wound at 3. However, the inductance …. uhf manual vhf manual hf manual hf automatic misc. The coils have taps to allow operation on different bands. I have given much consideration to the coils used, and to their placement in the loaded antenna. the (far) end of the wire is always a current minimum and a voltage maximum. MP-1 Portable antenna 70cm-80m w/ bag and more. 2" below the upper wire. With the extra loading the antenna covers frequencies from under 3. IT IS THE COIL Yes, the coil is the heart of an antenna, and WE HAVE STRONG HEART. In this case, we need inductive impedance. Loading coils are used because non-resonant antennas have considerable amounts of reactance at their feed point and the additional L c. I've been reading up on top loading with. Coil-loaded 40/80 Meter Inverted V Dipole Antenna by KG0ZZ. , John WB4YJT-0. Now touch the wire to each successive tap, moving downward along the taps (including the bottom coil end wire) until you find the tap that gives the highest. A couple of radio amateurs have put some nice pictures on the web that result to be very instructive in explaining how to construct high-Q loading coils: Mark Peterse, PA3HMP came up with an elegant design for the trap coils of his wire dipole antennas, solely based on standard PVC tubing. DIAMOND HVC7, HVC-7, 40m LOADING COIL MV3A/HV7A. (To better understand the variables. Controls the amount of shunt capacitance in the antenna circuit. Such a coil is obtained when the length of the loading coil is half the diameter, L/D = 0. Touch device users, explore by touch or with swipe gestures. A loading coil is used to resonate an electrically short antenna which is capacitive at the desired frequency. Download Instruction Manual. The following table gives you the length of the close wound section of our antennas. sebaiknya 24cm atau 1/8λ, putar sebanyak 6 putaran. The coil losses basically depend on the current, coil dimensions, material. sciencewriter. Modulator Antenna & Bent Loading Coils! By simonthewizard April 28, 2020 11 metres 11M 26CT104 Gary 27MHZ AM antennas cb funk cb radio cb radio antennas cb radio england CB RADIO UK cb radios cibi citizen band radio citizens band radio dx'ing FM on the air simonthewizard SSB UKCBTV. A loading coil is an inductor that is inserted into a. Note that the strength of the magnetic field is not an indicator of efficiency. No Ground Plane Base Loaded Chrome Coil Antennas Specifically designed for installations that lack a suitable ground plane When no suitable ground plane is available, these antennas do the job with a tapered loading coil jacket, chrome plated fittings and base-loaded matching network supporting the collinear or trilinear rod sections. 2kW, two air cored inductors wound on fibreglass formers, which function as traps on 40m and loading coils on 80m, plus lengths of 450 ohm ladder line and insulated copper wire to form the antenna elements. The gain is -0. Even the most efficient loaded whip won't perform as well as a full sized vertical, but by choosing one with a very high Q loading coil such as a High Sierra, you'll still radiate a reasonable signal, at a cost of needing to retune whenever you QSY any distance. VK5FQ website 12/02/14 Start build of new. 8:1 SWR at 3. Resonance may also be observed at each of the odd multiples. 3m) SSB Full-Length Conductors, No Loading Coil. The antenna is fed by a coax line that runs underground from the house to that plate, where the center conductor feeds right into the antenna. The RF is tapped onto the matching coil which is grounded at the base to inductively load the antenna at the proper impedance. (the bleed off coil is not connected to the caps, the image is skewed) So to recap, if your resonance point is too high, your antenna is electrically too short, and you can add a loading coil in series with the coax feed to lengthen it. I've been following this lumped coils stuff and bugcatcher loading coils, as many others, just to learn on the theory. high; used with art-13 transmitter. The antenna is strong enough to withstand almost any impact. A coil placed at the based of the antenna may be more. The original coil is designed for low power portable applications. The coils have taps to allow operation on different bands. In this way it radiates like a 5λ/8 radiator, but has the impedance of a 3λ/4 antenna. Sure we load them for mobile use all the time but for fixed use it's not that hard to figure out a way to get 16. 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. However, practical reasons necessitate use of a much shorter element, with a suitable loading. COIL IS 30% MORE SAFER. For example, from the top of the antenna:. The coil design of Wolf River Coils differs from other. In use, this new monster loading coil is positioned on top of my remote-controlled variometer to provide fine tuning of the antenna from the operating position in the shack. Thus at resonance, the resistive value of both the inductive reactance and the capacitive reactance will be equal, but opposite in sign. Ground Independent Multiband Antennas 6 m 40 m 20 m 15 m Capacity Hats Balun/ Choke Insulated tubing Mast Coax Vertically Polarized Loaded Dipole 40 m Loading Coil Center 2 m Fed Remember Hustler HF Mobile antennas? This is basically what this design is-only mechanically mounted on a mast Just put to two of them back-to-back and use three. Making a Remotely Switched Load Coil Now that you have built a flagpole antenna and the yard is filled with 32 buried radial wires to make a ground system you are ready for a tuner or better to make your own matching system. The whole thing was connected up and the shorter wire end connected to an 8m squid pole as a sloper antenna. Enter a length between 1 and 500 feet Distance from center of antenna to the center of the coil in feet (Must be less than half the total antenna length given above) Enter a distance between 0 and 250 feet that is less than half the total antenna length Diameter of the conductor in inches (14 gauge is. Since most PAs are designed with dedicated output matching networks to drive a standard 50-Ω antenna load, any possible antenna load variation may. The coils have taps to allow operation on different bands. The loading coil is supported about 6 inches away from the tuning cabinet and the tower. Distributed Coils. It is resonant on 20m without the added 40m coil, but requires a tuner for the other bands. Add to cart. That means it doesn't matter where the coil is. It is an extremely efficient air-wound coil which leads to better and more powerful performance. You can spot a VHF or UHF collinear high-gain antenna by the loading coils in the center of the whip. 4 antennae, GPS antenna, Lora antenna, GPRS antenna, 2G. If you add this coil to the end of a 40-meter EFHW element (~67 feet), and then add about 7 feet of wire on the fare side of the coil, you should be able to tune a narrow slice of the 80-meter band. 150 Watt power load. The placement of the coils does affect the shape of the current distribution, but does not change the fact that it is maximum at the feedpoint and zero at the tip. As with our other wire antennas, the user supplies the 15′ of 20-22awg wire for the driven element and four 10′ radial wires. A19880552000. Such a coil is obtained when the length of the loading coil is half the diameter, L/D = 0. More than a simple "flagpole", this complete antenna system includes adjustable base-loading coil, Guanella balun, and counterpoise. and a 17ft antenna arm, with the coil at 0 distance from the feedpoint, I get an inductance of around 50uH ,. Sign in to check out. K722 Product Description NMO loading coil only MHz 406-470 MHz Antenna 406-470 MHz replacement coil for ASP7650 MOSAIC series antennas Mfg. Each coil has 3 recessed channels which allow for nearly a hundred tapping options. (The power dissipated in the radiation resistance is the power that is transmitted. Years of refinement in the mechanical and electrical design of load coil products have resulted in the most technically advanced antennas on the market. I would still appreciate some. 3 show efficiency as the coil is moved higher. The whole thing was connected up and the shorter wire end connected to an 8m squid pole as a sloper antenna. From one end measure 2. The antenna is strong enough to withstand almost any impact. The coax feed is a small loop that comprises the split ends of the coax and about 1/3 of a turn of the copper tubing in the center of the coil. This current is going through the loading coil and will built up an antenna voltage of 8. Coil loss is therefore ~100 watts, or 50 watts per coil. Stainless Steel Construction. Changing the band just by changing the alligator clip is a very welcome option. On the negative side, raising the inductor reduces the capacitance to ground, with the result that more turns are required on the coil to resonate the. It should measure out to be about 50uh. Coil loading is a required aspect of many lower HF antennas but is not by any means efficient. Wound at 3. We install capacitors on our motors so tuning the antenna by ear is static free. As seen on his page, the original formula seems to come from an. I'm not so sure about the capacitance hat. A Loading coil is used just above the feedpoint, and the single radial becomes a part of. The hermetically sealed stainless steel housing ensures long lasting communication throughout your team’s. The total lenght is about 15mtr only and using 2 coils and a little stub (s) on the 80m coil or/and the 40m coil. when i built up a wifi antenna with a quarter wave GP and 7mm coil per youtube video that works great, why is the straight length past the coil much longer than 2. Figure 2 shows the EZNEC comparative gains (dBi) and radiation patterns. The method appears to be based on an equation in J. This antenna is still functional, but has been replaced with one of the newer Copper models in our HF mobile setup. The placement of the coils does affect the shape of the current distribution, but does not change the fact that it is maximum at the feedpoint and zero at the tip. 4GHz frequency by making use of a loading coil. ANTENNA PATTERNS. 5 turn per 25mm) Number of turns depends on the length of the antenna. "I have designed the coil using. However, practical reasons necessitate use of a much shorter element, with a suitable loading. This antenna is only 15m long using 2 loading coils. Loading, in communications technology, addition of inductance to an antenna or at periodic intervals to a transmission line to improve operating characteristics. The further the loading coil is from the feedpoint, the more range you will obtain. Using EZNEC, Woody calculated parameters for a base-loaded coil that would not only electrically extend the antenna but also eliminate. Modulator Antenna & Bent Loading Coils! By simonthewizard April 28, 2020 11 metres 11M 26CT104 Gary 27MHZ AM antennas cb funk cb radio cb radio antennas cb radio england CB RADIO UK cb radios cibi citizen band radio citizens band radio dx'ing FM on the air simonthewizard SSB UKCBTV. The telescopic antenna and the MFJ-67 loading coils are ⅜ " - 24 threaded and can be easily combined. 75 inches in diameter. 80M Base Loading Coil for the BigIR Mark IV Vertical. Antenna Loading Coil, ATC, CJP-47282. Description. 1 HV7A Mobile Antenna System General Information HV7A has 5 band capability—6m/2m/70cm, plus 2 HF bands though use of loading coils. The combination of the plate tuning capacitor and the plate loading capacitor can be adjusted to vary the voltage across the loading capacitor (and thus the antenna) to the optimum value. The MP-1 is a universal antenna with 180cm length and max. Broad banded to insure maximum signal strength over the UHF 420 - 470 MHz band. 4 meters) to resonate on our local NET frequency of 3. It will give the BigIR the capability to continuously tune from 3. The overall lenght is only 15m. Published in CML-47205 antenna loading coil. Loaded Quarter Wave Antenna Inductance Calculator. If loading is only to simulate longer antennas. In August of 2010, I finally lowered that antenna to the ground, in preparation for replacing it with a new vertical. High efficiency self-loading china batch controller self loading concrete mixer machine truck in Henan, China Contact the seller for additional photos and information. 83 MHz) vertical antenna. And, most important, until the giant coil antenna length exceeds 9-feet, then it will never, ever have gain over the 9-foot whip. The wire ends can then be screwed onto the loading coil. Lumped Load Models v. 67) electrical building wire was used. More than a simple "flagpole", this complete antenna system includes adjustable base-loading coil, Guanella balun, and counterpoise. An efficient antenna radiates most of the energy fed to it. The antenna wire lengths before trimming are 5. NOS Vintage Antenna Specialists KB-46 Low Band Replacement Load Coil 42-50 MHz. Removable coil for safe storage & garage entrance Weather Cap included to protect mount when coil is removed 2 year warranty Wilson 5000 antennas for their size, perform very well! Wilson and us are the few out there that actually make their antennas with silver plated coils. "Screwdriver Antenna" The antenna uses a high quality copper contact ring to make contact with the loading coil. Loading coils make more sense for a 160m, 80m or perhaps 40m inverted L if space is tight. Rugged, solid fiberglass core. If that's too long for you, you could add a loading coil for 30m just like in the 10/20/40 version. This experiment proves it. This leaves some plastic support at the high-voltage end of the coil. Download Instruction Manual. Aside from the hi-performance loading coil that maximizes the transmit/receive functions of your CB, these top-loaded antennas will also receive the NOAA emergency weather alert and. The gain is -0. Adding a loading coil to a 40m Vertical for 80m operation. uhf manual vhf manual hf manual hf automatic misc. It's not hard to tap the loading coil to allow it to be used on both bands. There has been much discussion in the rec. The antenna consists of a matching coil at the base, a short mast up to a loading coil and the requisite whip or stinger at the top. ) The loading coil helps to resonate out some of the series capacity resulting in more antenna. 87 mH loading coil. s • * Mount coil housing to the element unit using 4 (10-32x1-3/4) screws (Figure 9 & Figure 11). Many CB antennas lose more than 50% of the power put into them. Some coils are held together by clear epoxy ribs, others use scrap pieces of PC board and epoxy. The Maldol AH28 is a complete 10 meter antenna for the Yaesu FT-817. Before you get this antenna, I would like you to note that its RG 58 coax cable measures slightly less than 10 feet. ½λ vertical with a loading coil? Would it have the same performance? The antenna in this article, at only 2/3 the height of a full ½λ vertical does just that. Shiny streamer marks on the surface of the plastic show where the intense electric field has caused corona or "streamers". The telescopic antenna and the MFJ-67 loading coils are ⅜ " - 24 threaded and can be easily combined. How come? Well, the loading coil must always "trail" the antenna mast; that is, the coil must be directly behind the antenna mast when the vehicle is moving. 43 FOOT 10-160 METER MULTIBAND FOLDOVER VERTICAL ANTENNA WITH UNUN. RF current to the principal loading coil from the antenna tuning unit (ATU) which is located on the anchor post at a convenient height near ground level. Another type of mobile use for a loading coil is in a 2 meter, 5/8 wave length antenna (Fig. 79 Mhz, ideal for DX. 3 show efficiency as the coil is moved higher. To put it in perspective, I have an 80m hamstick, which is basically a 4' loading coil with a 4' whip on it. In layman's terms, it is like taking a 8ft whip, measuring off the desired antenna length, and wrapping the excess length into a coil. Once you have determined a suitable antenna spot in your backyard, provide a length of feed line to that point. The GS3 loading coil is a real work of art. getHighPassLocs(birdcageantenna) returns all the feed locations on the birdcage to operate the antenna as a highpass coil. High-efficiency air-wound 80/40 Meter loading coil with 3/8x24 male and female connectors. The Completed 80 meter coil Set up the PAC-12 antenna with radials and the 80M coil in place and check the SWR using a bridge or analyzer. The larger coils are made from 1/4-inch-diameter copper tubing. On 40m, because of the centre loading coil, the antenna is a full quarter wave resonant at about 7. 555 MHz with a 2:1 Bandwidth of 67Khz. Radio antenna. Tuning out the reactance is important because a tuned antenna will accept and radiate much more power than a. Barker & Williamson air wound inductors have been an industry standard since their introduction in 1932. The presence of the cabinet and the tower do not materially affect the operation of the loading coil. NEW! HOMEBREW BUDDSTICK PLANS. loading coil: A loading coil is an induction device placed on a local loop longer than 18,000 feet that carries analog signals. Depending on the mode and the weather this can easily damage the coils and render the antenna inoperable. (And all my responsibility is hereby disclaimed!) I haven't personally tested these designs, but others have and found them to be satisfactory. The yagi-uda antenna is the most recognized antenna. Dipole antennas are normally ½ wave but I will show you how to build a dipole greater than a ½ wave and still keep it resonant to the 2. Aug 8, 2014 - Homemade HF loading coil for short antennas. designed by long-time antenna aficionado James Bennett, KA5DVS. Tram 719 High-Power 3 000-Watt CB Antenna 16" Bottom Load Copper Coil. In this graph the horizontal axis represents the position of the loading inductor. antenna, has a whip radiator connected to a loading coil, both of which are supported above a ground plane by a mounting structure. Provision needs to be made to adjust the coil position. This coil is installed at the base of the antenna (it is mounted on the EHU) and turns the antenna into a bottom loaded vertical antenna (for 80m and 60m bands only). 600ohms @ 7. It is a principal object of this invention to provide an antenna adapted foruse in short wave transmission and reception and comprising a plurality of electrically conducting sections and simplified means for detachably connecting a loading coil of selected inductance intermediate said sections, whereby the transmitting and/or receiving bands from to 80 meters may be utilized, with the antenna. If you add this coil to the end of a 40-meter EFHW element (~67 feet), and then add about 7 feet of wire on the fare side of the coil, you should be able to tune a narrow slice of the 80-meter band. Any reputable antenna manufacturer will have coils that the current into and out of the loading coil ( the inductor ) should be close to equal. Wolf River Coils LLC is proud to introduce the Silver Bullet Platinum. The loading coil helps to tune out that reactance. and a 17ft antenna arm, with the coil at 0 distance from the feedpoint, I get an inductance of around 50uH ,. Diamond Antenna X200A. This is a shortened multiband antenna, about 23m long, for 80m-10m that offers low SWR (1. 150 Watt power load. The antenna is strong enough to withstand almost any impact. As a result, the required loading coil inductance to compensate the capacitance of the antenna at 1. Now touch the wire to each successive tap, moving downward along the taps (including the bottom coil end wire) until you find the tap that gives the highest. Antenna? Transformer is a 1:49 or 1:64 UnUn (not 1:4 or 1:9 used on random wire antennas) 50 Ohm Coax from transformer to station Multi-Band (works on all harmonics) Deploy it horizontal, sloping, inverted-L, inverted-V Commercial example: MyAntennas EFHW-8010-2K Pass it around (I want it back!). These are used by installers to form protective bushings around the edges of holes cut into sheet metal, and come in strips that are cut to desired length then snapp ed into the hole to cover the raw edge. 21" outside diameter) base provides a form for the coil, located near the base's top end. A design by VK3JEG is only 66-ft. 96 (10%) SKU: HVC21 Diamond. In layman's terms, it is like taking a 8ft whip, measuring off the desired antenna length, and wrapping the excess length into a coil. But most loop antenna based radios do the opposite. 2ft: 30x3x3 <1: Portable Sectioned aluminum tubing with fixed loading coil. (Received October 21, 1964; revised December 12, 1964) In this paper, a method is presented by which the distribution of current on some structurally simple coil or multi turn loop antennas may be obtained. Mark II Loading Coil. Traps for 80 / 160 meter band Dipole or inverted V tuned as a pair. The device is rated for 20W, has all stainless steel hardware for the antenna, loading coil, and radial connections. In use, this new monster loading coil is positioned on top of my remote-controlled variometer to provide fine tuning of the antenna from the operating position in the shack. All "KW" antennas exceed the requirements of any CB radio, new or old. Figure 2 shows the EZNEC comparative gains (dBi) and radiation patterns. 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. I would still appreciate some. diamond hvc21, hvc-21, 15m loading coil mv3a/hv7a. Free 2-day shipping. For magnetic antennas, you'll need to touch the center pin of the coax cable connected to the antenna instead. 4 PA Robustness to Antenna Load Variations. when i built up a wifi antenna with a quarter wave GP and 7mm coil per youtube video that works great, why is the straight length past the coil much longer than 2. Great SWR Match. This means that it has to be retuned more frequently than an antenna that doesn't need a loading coil. This means that I'll need to build a new loading coil, variometer and impedance matching transformer. The loading coil "extends" the length of the antenna electrically, but allows a shorter antenna to be used. Click to find the best Results for antenna loading coil Models for your 3D Printer. Optional 40m loading coil extension - $20. The coil windings are inside the sturdy fiberglass tube, which Gary molds around the loading coil. A vertical antenna (effectively half a dipole operating against a ground plane) is resonant at one-quarter wavelength. Termination loss is 6dB. UPDATE: Added two variations on the coil for someone who wants to use it for a screwdriver antenna. I built this loading coil to replace my original loading coil described above. 1919 "buddipole loading coil" 3D Models. The loading coils should be as far from the center feed point as possible, bearing in mind that as the distance for the feed point increases, coil size increases and the self-resonant frequency decreases until it reaches the operating frequency, at which point coil Q decays to zero, and the antenna efficienty approaches zero. The SteppIR 80m Loading Coil: The SteppIR 80m coil is designed to mount on the base of the SteppIR BigIR vertical an-tenna. A little extra wire is necessary for terminating the 80m tail on an insulator and also to allow some adjustment for resonance in your favourite part of the band. I've decided, for the time being, to keep my 2200m (136kHz) antenna tuning system separate from the 630m system. This loading coil is used to resonating the vertical radiator into a frequency near the targeted frequency. 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. SteppIR Antennas - 80m Loading Coil Kit 6 BigIR MK III Procedure to add 80m Coil: • If you have purchased the MK III and the coil together at the same time, skip the *teps. You can spot these antennas easily by a single yard-long whip and a gray. 6 ohms, as measured. com Home Mapsite Add Link. This program uses different formulae for 2, 3 or multi-element designs and includes element tapering Verticals covers all the common types with a coil calculator built in for the antennas that require them. I recommend tuning so that. antenna, has a whip radiator connected to a loading coil, both of which are supported above a ground plane by a mounting structure. C) Leave the 4 – inch pigtail feeling the antenna base And use a. long, about the size of a 40m dipole. But most loop antenna based radios do the opposite. These all came from packages marked 72 & 75 MHz receivers. A lumped loading coil may be a short, fat, single-layer solenoid. Linear loading has similar efficiency challenges, and with greater vulnerability to ice. 4415: 2112 116th Ave NE Suite 1-5 : [email protected] I used the same dimensions as VK3CAE 6. This shield presents a conductance to the feed point which varies depending on how long the coax is, in electrical wavelengths, between the feed-point and ground; Worst case, the. The worst mistake I made was thinking matching coils were an exact science when the exact opposite is true - matching coils can be big or small, air coil or iron powder (but never ferrite) core, horizontal, vertical, wound around a toroid or any combination of these. 1910 Fax: 425. The loading coil is the answer. B) Adding a coil from antenna to base round along with the. The antenna circuit of your set will pull the antenna in line but with quite a bit of impedance mismatch and losses. 0 is based on 0. The current on each section of the antenna is the superposition of forward and reverse traveling waves. The loaded antenna provides three more independent design variables (load position, load resistance and load reactance) than an unloaded antenna of the same length. A standard dipole antenna is resonant if constructed with a length of one-half wavelength. Compatible with automobiles, trucks, vans, motorcycles and ATV in a single antenna configuration when metallic ground plate is available. Antenna Loading Coil Calculation The calculation method is taken from a BASIC program by OA4/KA2OIG who is hereby acknowledged. 555 MHz with a 2:1 Bandwidth of 67Khz. 5”) Hand-wound loading coil is factory tuned and tested to ensure peak performance at a specified frequency. In this configuration, it's the matching coil that really makes the antenna. A transmitting and receiving antenna, e. Once you have determined a suitable antenna spot in your backyard, provide a length of feed line to that point. HF/VHF (7114121128150MHz) Loading V type Dipole Antenna HFV5 Operation Instructions TO use this antenna properly. Any reputable antenna manufacturer will have coils that the current into and out of the loading coil ( the inductor ) should be close to equal. nov 13, 2014 - 43 foot multiband vertical high q add on 80m loading coil--new | zerofive-antennas. Wolf River Coils LLC is proud to introduce the Silver Bullet Platinum. , at the feedpoint) requires the smallest amount of inductance. To the left is the 3/8-24 mounting bolt. Warranty 2 Years. Antennas L-L are linear-load with a 4' loading element of #12 wire in a vertical plane, with the upper wire 1. 1920 "antenna loading coil" 3D Models. While mobile installation is the dominate application for our coils, they can be used for apartment dwellers, amateurs dealing with confined space or stealth antenna installation, portable applications, camping or anytime you need to load an antenna without the need of a tuner. When the loading coil is installed at the bottom of the vertical radiator, we call it a "base loaded" antenna. By using a mobile antenna loading coil you will minimize ground related losses. Coil-loaded 40/80 Meter Inverted V Dipole Antenna by KG0ZZ. The antenna above is my Texas Bug Catcher. the antenna can be matched to coax by using loading coils • For best results, the coils are placed in the middle of each leg of the dipole • Loading coils can introduce additional loss of 1 dB or more • For dipoles longer than /3 the antenna can be matched to coax by using linear loading. The loaded antenna has pretty narrow bandwidth - about 40 KC 2:1 SWR range, which I view as a good thing - an indication that there isn't a lot of loss. 7%, but at 1700 kHz it's a whopping 5. JBC2400 2ft Low Profile CB Antenna, Motorcycles, Pickup Trucks. 88") at 0°C (32°F).