Efhw antenna length


What about a thicker antenna? For sale here is our End Fed Half Wave (EFHW) antenna for 10m-80m. 30 Jun 2019 QRPGuys, Portable No Tune End Fed Half Wave Antenna, Kit Parts First and foremost, true EFHW antennas use a half-wave length of wire to make for a more efficient radiator. •Requires a 0. Parts Inventory 1 - Tayloe SWR Indicator kit 1 - T50-6 core (yellow), T94-2 (red) core not used for 40m-10m 1 – poly-varicon, w/shaft and mounting hardware 24” - magnet wire for the toroid I would use a flag pole mount with a dowel (or pvc) to get away from your siding a little bit. Any counterpoise should be at least 1 foot above ground running away from or perpendicular to the antenna wire. 08") May 10, 2019 · In the mid-1980s, Brian Austin (ZS6BKW) ran computer analysis to develop an antenna system that would match the maximum number of HF bands possible without an antenna tuner, using 50-ohm coaxial cable as the main feed line. 9 feet long and the twin lead is 31 feet long. 94 feet). The feed-point was about 4' above ground, sitting outside on a window "ledge". k. It's up to the designer to select the best design for the job at hand and to utilize that design in the most efficient way. This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. With a power One popular antenna that is being used increasingly is known as the end fed half wave antenna, or EFHW antenna. Electromagne2c' Wave'Polariza2on' • Electric'and'magne2c'waves'are'at' right'angles'to'each'other' • Magne2c'wave'dissipates'within'a' few'wavelengths'of'antenna After installing the antenna, measure the SWR to find the resonance of the antenna and note it. Shorter length counterpoise wires can be used if operation is confined to 40m or higher. The counterpoise wire does not have to be similar in length to the main radiator wire and just a short wire is all that is needed, about 0. I decided to just use a  8 Aug 2019 I have a 80m EFHW that I'd like to use on 60m and 160m if possible. Theoretically, without a return path, the antenna won't radiate at all. The problem with an end fed half wave antenna is that the antenna MFJ-17754 40/20M Dipole Antennas are shortened, coaxial-fed, 42 ft. A second length of feedline runs from there to the shack. That means that the matching characteristics of, say a 40m EFHW will be very similar to those of a 20m EFHW. Aug 22, 2016 · The antenna cannot be an actual 1/4 wave length on any ham band. To move. Components of a End Fed Half Wave Antenna ••Radiator length is 1/2Radiator length is 1/2 λoftheoperatingfrequencyof the operating frequency. 80m, 67ft on 40m). Let’s view VSWR and Return Loss of the antenna feed point vs. Put it horizontal at 20 to 30ft off the ground and it will be a great NVIS antenna on 80 and 40m but will also make DX contacts there. This is a nice full length half-wave dipole antenna for 20m. Other useful information would include your experience with similar products, infomation on a product that you would purchase instead of this one, and so on. QRPGuys Multi-Band End Fed Antenna, 40/30/20m – $40 Due to the interruptions of parts delivery from COVID-19 repercussions, we are having to suspend taking orders temporarily. This is best described in pictures: Nov 17, 2010 · The End Fed Half Wave antenna described is a very good choice for those operators who have limited space and require an effective radiator. Three popular lengths for the antenna are these: a. I wound a new transformer, but now on a thinner plastic tube. C. Unlike many END FED antennas on the market, this one does not require the Antenna Tuner to operate. A half-wave at the lowest band of interest will also work well on all harmonically-related bands which has become particularly attractive to those wanting a quick portable wire antenna. However the physical length is slightly different to that of a half wavelength in free space. Being a ham radio antenna, the many of the higher frequency bands are harmonically related, and therefore it will perform as a multiple number of half Multiband end fed antennas 3. HFEDZ 10M-80M END Fed Half Wave (49:1 EFHW) HF HAM Radio Antenna - $84. We sell MyAnt EFHW-8010-1K Multi band End Fed Half Wave Antenna at Radioworld UK for all your Wire antenna needs call 01922414796 Optimal Length of Random Wire Antenna J. End Fed Half Wave Antennas VS Random Length End Fed Antennas Steve Ellington EFHW Antenna The random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the math, getting the center insulator built or bought, running the feedline, and all the rest that goes A special case of this, is the End-Fed Half-Wave (EFHW) antenna. Typically for random wires we go out of our way to avoid half-wave lengths so that, for a range of bands, the impedance doesn’t change too drastically. Fully understand every voltage, resistor, capacitor, transistor in the circuit and the performance of the EFHW antenna. The difficult problems associated with random wire or long wire antennas are caused by ground currents and radiation from the single wire feeder. This article will not address that antenna type. But I don't PicClick Insights for " HF End Fed Antenna Transformer MEF-330-2K for EFHW antennas-2kW ICAS 80-10m " PicClick Exclusive I only need about 55' to cover down to 80 meters. With this design changing bands can be done in no time thaks to the traps. 5:1. May 29, 2017 · Comparison between the EFHW and Dipole on 20 meters. A shortened multi-band End-Fed Half Wave (EFHW) antenna for 80-10m Steve Nichols G0KYA A shortened multiband antenna, about 23m long, for 80m-10m that offers low SWR (1. This type of wire antenna is a half wavelength long at its lowest frequency. End-Fed Longwire Antenna with a 9:1 UnUn rated at 700 watts, covering 160 meters through 10 meters, only 124' 6" long. My preferred antennas these days are  It rises vertically approximately 14" away from the tower legs for 52' then horizontally to a neighbor's tree for its remaining length. As the name indicates the EFHW antenna is half a wavelength long on the lowest band of operation. A. Which is correct, or will they both work? The lowest impedance presented by a single counterpoise wire is when the counterpoise is resonant and 1/4 wl long electrically. 95 DESCRIPTION We are delighted to introduce these fantastic USA manufactured antennas to the UK. 8 metres long. 99. Resources listed under 30 Meter Antenna category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. I needed an antenna system capable of the lower HF bands. I came across EFHW antennas a while back when I was just starting to figure out antennas. Model Data by Harmonic The following data are for the far field radiation patterns and 3D color views of an End Fed Half Wave Inverted-L antenna with a long, straight radiator at 40 feet and feed point straight down near ground. the coax as the return path for the minimal antenna currents. I run a simple EFHW balun that was like $36 on eBay. Another popular portable-use antenna is the random length wire and tuner combination. 130-140' (best, if you have the room and want the strongest results on  link end fed half wave antenna and tuner for sota designed to work on 15m 20m and 40m . “Counterpoise” Length We look at the magnitude of the impedance of an EFHW “antenna” for short counterpoise lengths. If it doesn’t then the 5 band EFHW is better as it can be built to need no tuner on the 5 bands. The feed impedance at the very end of a half wave is thousands of ohms, usually somewhere between 2000Ω to 5000Ω, which we need to match to our 50Ω transceiver. With the above two situations in mind, it’s time to explore antenna characteristics as the feedline changes length. This is a fantastic antenna that is easily out performing the SR320A that has been my go to antenna. Since then I have employed use of SimSmith by AE6TY to refine the analysis in conjunction with EZNEC. 065", 12 gauge is . Total length in feet. This formula takes into consideration the capacitive "end-effect" from insulators which shortens the physical length requirement for the equivalent electrical length. It comes in 200W, 1,000W and 1,500 W ICAS (Intermittent Commercial Service) versions, which differ mainly in the beefiness of the matching network and has a little brother in the half-length (63 feet) EFHW-4010 10-40M version. Dec 28, 2016 · Simple End Fed Half Wave for 40m (and how it works) of the EFHW is that unlike most QRP antenna couplers, there are no variable capacitors used that typically can Aug 12, 2016 · You can’t, for example, generally use a 40m EFHW antenna on 20m. 82. Much has been written about the optimal length of a random wire antenna (sometimes called a long wire antenna), some of which is contradictory. 4 sold. I decided to just use a few jumper wires chained together to create a counterpoise, with a total length of about four feet. I have changed the counterpoise wire from 1. As mentioned before the lengths are a little variable according to the exact nature of the antenna. long dual-band resonant antennas. Curious to see what the power handling was, the matcher high impedance output was connected to a similar matcher using a larger FT140-43 core that transformed the impedance back to 50 Ohms. The antenna works pretty good for MW all the way to the 2 meter band (don't see anything on the 160m band though). This formula to obtain the length of a half-wave dipole antenna will give a good ballpark value to start with. If you are looking for an antenna that will cover 160 through 6 and work efficiently… that hasn’t been invented yet. Antenna? ○ Let's call it a “EFHW”. Using the EFHW for 20m at GB0CMS 3. Let us not confuse the End-Fed Half Wave antenna with the Random Length End Fed wire. A random length of wire (~41′ is a good length for 20/30/40m on my KX1) will present a range of impedances depending on the frequency. An end fed half wave antenna is one of a specific length depending on the frequency that it… Mar 27, 2017 · Here's a few antenna matching devices I've gathered and some experience with the antennas. END FED 6–40 Meter Multiband HF Antenna Introduction This EARC project produces an inexpensive, multiband, end fed HF antenna matchbox that is quick and easy to setup and use. The antenna wire can be used in numerous configurations, although the inverted L and sloper seems to work best. A tuned Unun is handy if the Unun is located at a convenient location for tuning. What else affects Antenna Impedance? From above we see higher antenna resistance is a good thing for current, and length is not overly critical. The wire I used came with plastic hooks so it could be hung up as a “ClotheSline” and I use one of these as the end of the antenna – folding back rather than cutting, so I can adjust the length on site if/when required. Oct 17, 2017 · Facebook Group - EFHW Antennas Steve Ellington N4LQ started up a group on Facebook called End Fed Half Wave Antennas. I have had to bend the wire radiator in zig zag and multiple 90° bends to fit it in the available area and it still worked well. This allows me to adjust the antenna's length easily in the field if necessary. MAKE ALL LENGTH ADJUSTMENTS IN THE HORIZONTAL LEG OF THE ANTENNA. 5 metres to 6. 92 feet total length for a 40m dipole. * * * A Bad Rap? The final antenna design has effective radiation patterns from 160 to 10m and looked like it was worth building even though the gain figures were modest comparable with vertical antennas. Start winding the Matching Auto Transformer, each pass through the center of the core equals one turn. We also see lower reactance is a good thing for voltage, and length can affect voltages (and the electric field) surrounding the antenna and counterpoise near the feedpoint. Introduction. Pretty much everything about this antenna system is random save the length of the nominal radiator. Describe your experience with the EFHW-8010 8-band End Fed Half Wave antenna and tell us why you give it the rating you did (required). Unlike many END FED antennas on the market, this one does not require the Antenna QRP Multi-band HF EFHW antenna for SOTA Post updated 29 September 2017. They have twice the resistance of a single-direction antenna. Unfollow end fed antenna to stop getting updates on your eBay Feed. Anymore I Element length seems about right for a 75/80m length. I do run a tuner though. One end goes straight into the rig, often with no feedline, and the other end in the air attached to something as high as you can find. May 28, 2013 · Utilize a very simple CW transmitter coupled to an EFHW coupler and able to transmit 5watts, 500milliwatts or 50milliwatts output power. Since  The random wire antenna is probably one of the least expensive, easiest and cheapest HF antennas to use if you have a tuner and you want to get the "most" out of a length of "random" wire without having to pull out that calculator, doing the  1 Jun 2019 3. This is a design by my friend John, KN5L. Counterpoises are commonly added to shunt common mode reflections when operating outside of the wire's resonant frequency to avoid RFI issues ("RF in the shack"). 3:1) on 80m and 40m, and below 3:1 on 20, 15 and 10m. the maximum workable frequency at the corresponding half wave length. NREF Antenna Secrets How to determine the wire length to use (antenna, coax and counterpoise lengths) How to match the antenna to coax cable (matching unit values and placement) Choosing a configuration that fits the location (vertical, sloper, inverted L, horizontal options) Choosing a feed line choke or noise filter Mar 02, 2016 · QRP Multi-band EFHW antenna for SOTA. 5-30MHz; Wire length ~130 feet; Power Handling: 200W I. These can be buried – the exact length of the radials is  8 Aug 2014 Coax feed line between the impedance matching unit and the radio is a 2 metre length of RG58AU. Feb 07, 2017 · At first I thought it was the radiating antenna wire running the length of my house and about 20ft above it. Adding the unun and a short length of coax to connect to the radio brings the whole aerial system up to a grand total of 200g. Jul 19, 2016 · More on the EFHW Antenna. I hope to post an update to the blog in a day or so. Model Data by Harmonic The following data are for the far field radiation patterns and 3D color views of a straight End Fed Half Wave antenna at 40 feet over "Real ground". I've heard that it should be 1/4 wave, and then again I've heard it should be 1/2. Jan 08, 2020 · ANTENNA& SET-UP: I put up a mono-band end-fed half-wave (EFHW) antenna - 66' in length - for use on 40 meters several months ago. Easy to Install and Use KM5M on 23rd Apr 2014 The NI4L end-fed 40-6m dipole antenna is just about perfect for portable operation. For many an End Fed antenna is the easiest solution to their property. 2:1, a bit higher than the Link End Fed Half Wave Antenna and Tuner for SOTA. What is an End Fed Half Wave. When a single counterpoise wire is near 1/2 wl long and resonant, it MyAnt EFHW-8010-1K Multi band End Fed Half Wave Antenna £159. The transceiver plus antenna was placed in a calibrated chamber for EIRP measurements. A simple tuner  14 Nov 2018 A half-wave antenna is a resonant radiating element with an electrical length of one half-wave. This provides the antenna radiator something to push against, by attaching a counterpoise wire to the common point of the auto-transformer. ○ Works on a similar principle to a Zepp and J-Pole. When an antenna that is one half wave length long has RF energy applied to it at its resonant frequency a standing wave develops  We provide two sizes for our EFHW antenna models, the 16AWG XLPE for 1K models, and 14AWG XLPE for 2K models size wires. (You can use the above 4NEC2 antenna model to see what happens at specific elevations and bands). I said it might, and that it might be worth trying as an experiment, on the bands where the antenna length is not resonant or close to resonance, that is, 12 and 17m. Adjust length as necessary. Note: The swr on the EFHW was about 1. Many factors will affect their exact value. " The very valid reason for this is that the high impedance of the feedpoint was outside the range of most transmitters and external tuning units. > > The solution for portable work is to use a length that is not a > halfwave - 58 feet is known to work well for 40 thru 10 meters when > used with a 13 foot counterpoise. What I discovered is that it provides a good SWR without a tuner on 40, 20, 15 and 10 meters. With the tuner in my xiegu x5105 I can also use it on 30, 17, 12 and 6 meters. Question I have is about the coax. You choose your hf band coverage depending the half wave wire length used. My take on a QRP EFHW inverted V antenna designed for use on three amateur radio bands 15m, 20m, and 40m. There are two popular ways of producing a multiband EFHW antenna. Then use an insulator to mount the balun. 0 MHz rated at 2 KW (SSB) The DXTREME models are the ultimate end-fed antennas with the capability of covering from 160-6 Meters and able to handle legal limit power handling with ease. Can a ground stake at the base of the feed point serve as a counterpoise, or does it need to be another wire running under the ground below the antenna? End-fed horizontal wire, an EFHW, offers the perfect solution for a wide range of All-Band 80-10 Meter End-Fed Half-wave Antennas - MFJ 1982,1984 End-fed horizontal wire, an May 13, 2015 · MEF-330-1K Multiband EFHW Antenna Transformer, Covers 8 Bands / 80-10m / 1kW-max. When fed from the center, a dipole makes for an easy impedance match to 50 ohm coax. The following tables show the recommended lengths to use for antenna wire based on the bands you wish to cover. If fed at the end (a. The direction of radiation is the Blue trace on the polar graphs. The result? Many years ago I moved into a house with a small garden of about 45 ft. If you do have RF problems you can connect an earth or short (1m) counterpoise to the earth (green) terminal. Initially it had a 10:1 ratio, but after some initial tests at home I removed some turns and now it is 8:1. 2 m or ≈14 ft for an 80m end-fed. It will also be tricky to match the antenna on other bands, particularly where the antenna is a half-wave long at your operating frequency and presents a high impedance at the feed point. If the antenna is shorter than a quarter wavelength, it suffers from the same efficiency problems as the vertical antenna. (You can use the above 4NEC2 antenna model to see what happens for specific elevations and bands). HF END FED Antenna EFHW-8010-HP 1500W 80-10m / NO TUNER NEEDED!! / 130 feet long - $255. One solution is to choose a length of wire that offers neither a particularly high or low impedance on any of the bands you wish to operate on. Any length of 50/75 ohm feed line ok (over 35 feet minimum) but longer feed lines Jun 12, 2019 · Figure 6 has little current on the feedline while figure 7 has lots. Counterpoise wire length. Jun 11, 2012 · OK, call me an antenna snob, but in my opinion the End Fed Half Wave antenna is about as good as it gets for an easy to put up, great performing antenna. End Fed Half Wave Antenna Coupler Schematic – 7-30MHz For calculating the length of a half wave in metres, I use 141÷ƒ(MHz) for wire elements. Mechanically is an end fed but electrically will operate as a full half wave on your desired operating band. No counterpoise needed but grounding is recommended on permanent installations. Aug 31, 2014 · The antenna was then set up using a 4. EFHW-8010-1K Multi-Band End Fed Half Wave Antenna. Hi, For sale here is our End Fed Half Wave (EFHW) antenna for 10m-80m. wa7ark 3 What is an End Fed Half Wave Antenna? Let's call it a “EFHW” Works on a similar principle to a Zepp and J-Pole ~0. In the graph below I have plotted what MININEC predicts for the impedance of an end fed half wave antenna versus the "counterpoise" length. A dipole can be fed anywhere along its length. 468 ÷ freq (mHz) = Length (feet). Here is a link to my take on the EFHW antenna and a QRP tuner Loss in a Deployed End Fed Wire and 9:1 Unun (update) This is an update to the blog post about loss in an EFHW. 2019-07-21 After putting up my 40 meter end fed half wave antenna discussed below and reading comments on Facebook about EFHW antennas I decided to do some testing. I support the feedpoint on a push-up painters pole on the rear of an RV trailer and drape the wire over a nearby tree branch. Mar 09, 2010 · How to create a counterpoise for an EFHW antenna is hotly debated. 0. 47 free space wavelength) was determined by modeling the length required to obtain resonance (jX = 0) when the "counterpoise" was the same length. Note: My (A to B) length was 6 inches. 0 to 54. Oct 05, 2016 · An end-fed halfwave, often referred to by the acronym EFHW, seemed to be a good choice, as it only requires a support at the far end. / NO TUNER needed / wire not included/one End Insulator included Product Description MEF-330-1K Multi Band End Fed Half Wave Antenna Transformer This is an End-Fed Dec 17, 2014 · I understand the basic theory behind how the antenna works. Nov 08, 2016 · End Fed Half-Wave Antennas Half wave dipole antennas are generally considered the reference point for all antennas in ham radio, especially on HF. If you have a tuner, then the 80-10 EFHW is easier as it is lighter, smaller and less fragile given it has no traps. . A so-called random wire antenna is an end fed antenna. Top - Amateur Radio Antennas - EFHW LNR Precision EF-10/20/40MKII Examination AWG wire wrapped around a . It is basically an end fed half wave dipole on 20m/40m and an end fed full wave dipole on 10m. Aug 08, 2014 · Hi Garry, nice arrangement with the center support, I like it. Thanks to Jon AF7TS for the suggestion and discussions that led to this article. EFHW-8010P- 200W Portable or Stationary Multi-Band End Fed Half Wave Antenna This is a 200W version of popular EFHW-8010 End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. Jun 30, 2019 · To match the impedance a typical radio requires (50 Ohms) you need a way to transform or match the impedance. Here is the Link to his article. The antenna could be used as either an inverted V or a half wave vertical on the higher bands The challenge with the EFHW is feeding it as the end is a high impedance point (apparently between 2000 – 6000 ohms depending on the surrounding environment). First 2 turns twisted section,  21 Jun 2016 The feed line is often of arbitrary length, arbitrary route, and it may connect to real ground via an arbitrary impedance. The EFHW is an ideal antenna for SOTA, it’s easy to deploy and can be fed with a sort length of coax. Non-resonant antennas may be force-fed using ATUs in conjunction with baluns or feedline current chokes. 5MHz) therefore also resonant on second, third and fourth harmonics etc. The results are conveniently displayed in inches, centimeters, feet and meters. The most common half-wave antenna is the center-fed dipole, whose Unlike a commonly used End-fed antennas with 9:1 UNUNs and non-resonant length of wire, EFHW antennas are not prone to high common mode current and problems associated with it mainly due to the high common mode isolation of the transformer (MyAntennas designs) and use of the resonant length of wire placing the current minima at the feed point. This article will initially concentrate on the half wavelength of wire and its use as an effective multiband antenna. 4 inches. 3. 5 Wave-Length wire on lowest band (130ft on My experience is a coax length of 1/4 wavelength of the lowest band is helpful in some setups. Distance from center of antenna to the center of the coil in feet (Must be less than half the total antenna length given above) Diameter of the conductor in inches (14 gauge is . The recommended setup for this antenna is for a . The antenna at the QTH of G4WIF So I stretched a 5m length of wire from the matching transformer to a nearby tree. For a Loop antenna the length also depends on the shape of the loop (Triangle, Rectangular, Square, Round) but start with a full wavelength for the band you wish to work on and tune from there. I like to use wire with a soft insulation and loop the extra length at the far end back upon itself and tie it in an adjustable knot. You can also add perhaps four or more wire radials at least a quarter wave long at the lowest frequency of operation, running out from the earth stake along the ground in different directions. The total overall length of the EFHWA is an electrical half-wavelength, calculated from the formula L (Ft) = 468/F (MHz) where L is the overall wire length in feet and F is the desired operating frequency in Megahertz. I have built a number of these on different bands and found the design extremely repeatable. 96 feet for a dipole on 20m (each leg 16. May 03, 2019 · They’ll both be a lot heavier, but they’re probably a lot more manageable than picture hanging wire. From the feed point the total length is 20. The antenna is probably too long. Test shows field strengths are identical. Power ratings are in Watts PEP for SSB/CW modes, with 50% or less transmit time (ICAS). 5 – 30 MHz This is a 200 Watt PEP step up transformer for end fed full and half wave antennas without radials, designed as a 200 Watt PEP upgrade by PA0EJH for the originaly Par Electronics designed 25 Watt HF endfedz multiband end fed antenna. Sprott Department of Physics, University of Wisconsin, Madison, WI 53706, USA April 26, 2012. Sep 26, 2018 · End Fed Half Wave (EFHW) Antenna Upgrade Part 1 - The Matching Transformer For several years the EF-10/20/40 MKII “EndFedz “ has been my main station antenna for HF. 160 meters band antenna category is a curation of 141 web resources on , 160m DX Mobile Aerial, Hex-Shaped 160 Meter Receiving Loop, 160m Vertical. The end fed half wave antenna is a classic HF antenna. END FED antennaEFHW-8010-HP Multi-Band End Fed Half Wave Antenna- NO TUNER NEEDED! EFHW-8010-HP 1500W Multi-Band End Fed Half Wave AntennaThis is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. Bi-directional - These antennas are able to capture signals from two directions. The directional options for an end fed antenna include: Single direction - This type of antenna has the least amount of resistance and the longest distance capture for signals in a specific direction. Random Wire Antenna Lengths. My take on a QRP HF EFHW inverted V antenna designed for use on five amateur radio bands… Dec 09, 2018 · All resonant HF antennas – ALL OF THEM – used outside their resonant bandwidth require the use of a tuner. £146. Aug 06, 2017 · The resonant EFHW is not much different than a center fed dipole of the same length except you are exciting it from one end. This is a unun ( unbalanced to unbalanced ) transmission line transformer designed to match 2450Ω to 50Ω . Stainless Steel hardware; Frequency coverage: 3. The end fed feature adds portable convenience, but does present another issue. Different sources tell you to make the counterpoise wire different lengths, some even say that you don't need a counterpoise. However, just because an antenna can be made to work is no guarantee that it will perform efficiently. I have found this calculation to work well, however it depends on many factors  To me the only obvious advantage is not having to deploy a counterpoise-with the end fed usually the length of coax will act for this, and of course the need for a suitable Un-Un,usually 9:1. Its’ feed-point affects its impedance. I made a new Link Multiband EFHW for 15/20/40 2 weeks ago. It is inversely proportional to the frequency which means the wave with higher frequency will have shorter wavelength. QRPGuys Wire Antenna Trap Kit – $15 Due to the interruptions of parts delivery from COVID-19 repercussions, we are having to suspend taking orders temporarily. The above graph is an actual scan of the author's ZS6BKW using an AIM-4170D antenna analyzer. An EFHW is simply a half-wave length of wire and a matching device, and that's it. This one does not require the Antenna Tuner to operate. This calculates to ≈ 4. NEW 300W PEP VERSION!!! Easy and fast installation. 5' of wire (read that was a good length for multibrand Rx/Tx), raise it 30' up and use good components. The VSWR was slightly worse, but still fine. I am very curios where that “stands” in your ranking of favorite portable/SOTA antenna … 13 Nov 2012 Since may of all of these EFHW antennas use the coax as a counterpoise, what is the minimum length that is required for the coax? If I sit on my deck and put the matching box 2 feet from my qrp rig will it still give me the results  9 Mar 2010 How to create a counterpoise for an EFHW antenna is hotly debated. The EZNEC screenshot below is the current distribution on 15m. WSPR Antenna Comparison (Loop vs Dipole vs End Fed) Over the last few months I have been playing with WSPR and I wanted to be able to use it as a rough way to evaluate the relative performance of different antennas. Posts about EFHW Antenna written by Andrew Williss. Of late I’ve been using this antenna mainly with my KX2. The EFHW Nov 13, 2012 · With EFHW antennas using an adjustable matchbox there is a great willingness to use the tuning of the matchbox to “fix” a detuned wire or a wrong length wire. The trick, therefore, is either a more capable tuner - see AA5TB's excellent page for EFHW info - or, addressed below,  For calculating the length of a half wave in metres, I use 141÷ƒ(MHz) for wire elements. Typically a 49:1 or 64:1 transformer will put you in the operating range sweet spot needed when you use the appropriate length of antenna wire. To run 60m Here is a 160m on up EFHW antenna that I recently built and deployed. I added a 1:1 choke at the end of the feed line running from the feed point to the ground. Different sources tell you to make the counterpoise wire different lengths, some even say that you don’t need a counterpoise. If properly implemented this antenna can be very good. This is the length of wire right from the tuner terminal to the insulator at the far end. If you make it the right length, then it will present a good match to your feedline, but if you have a tuner, and either place it near the antenna or use a low-loss feedline, then that doesn't matter. 05 wavelength counterpoised to be used. Apr 13, 2017 · The fastest way to do that, and put out a decent signal too, is with the EFHW - an antenna with a forbidden length. IF you do that its not an EFHW as its now a random wire with a random wire tuner and one must use a ground or counterpoise to work against. The EFHW antenna is a popular choice among VK SOTA activators. Cutting the length slightly longer than required and then trimming to obtain the best operation is always the right way to set up the antenna. Unfollow antenna end fed to stop getting updates on your eBay Feed. These dimensions were derived from modelling the antenna in EZNEC . 85 inch form resulting in a winding length of 1. These End fed antennas are unique, as they are resonant on 8 bands and DO NOT require a tuner to operate. 05 λ. For example a 32 foot length is actually a half wave on 20m with an impedance of about 3500 ohms and requires a 50:1 balun. ○ ~0. 87 results for end fed antenna Save end fed antenna to get e-mail alerts and updates on your eBay Feed. The problem with the EFHW, the reason that it is "forbidden", is that it has an outrageously high feedpoint resistance at resonance - on the order of 3000 ohms. com: End Fed EFHW-8010P 80M-10M wire antenna: Home Audio & Theater. A shortened multi-band End-Fed Half Wave (EFHW) antenna for 80-10m The 80-10m EFHW This is a shortened multiband antenna, about 23m long, for 80m-10m that offers low SWR (1. A ‘Windom’ type off centre fed dipole (fed 38% along its length) provides around a 200Ω feed. Now remove the resistor from tuner and connect the antenna. It is resonant Half wave on 80m (3. a EFHW), antenna impedance is in the 2000-4000 ohms range. The NEC file of the Terminated Inverted U antenna can be downloaded here. Antenna Projects for the 10 MHz - 30 meter Band category is a curation of 18 web resources on , Bobtail Curtain for 30 meters, 2 Element 30 meter Yagi Antenna, K7EA 30 Meter Ground Plane Antenna. This suggestion is based on my understanding that only a very small counterpoise is needed with a true end-fed half wave, because the antenna is fed at a current minimum. If you only have one support a GEK HF Multi Band Antenna may suit you better. As typically installed, it is a compromise antenna but great for portable use because it is easy to pack and easy to install. Should be a two step process, measure resonant frequency, compute length ratio for desired frequency, adjust length. 5 wave at 30m, which would be Install the antenna in a manner similar to the way you are going to use it. ~468 / freq in Mhz. 80  8 Nov 2016 Half wave dipole antennas are generally considered the reference point for all antennas in ham radio, antenna required a fair amount of trial and error because the 30 meter element and tuning stub length interact and affect  The Antenna: The antenna proper consists of a length of copper or copperweld wire, with a center feedpoint. A 9:1 Balun For Your End Fed Antenna End-Fed antennas do have their place in radio and other communications work. All orders that are in process will be filled and mailed to the best of our ability. 73 No, it is not needed, but it can improve the antenna system. Lowering or modifying the antenna is no longer necessary. ○ Fed from one end using a  Amazon. Because electrically my antenna is half a wave on all three band, I don’t need the blue cap in the auto transformer (more about that later). One of the earliest examples was the Zepp antenna Apr 24, 2017 · While searching for an alternative to my Linked- Dipole I tripped over the posting of Pedro, CT1DBS, illustrating an end-fed half-wave (EFHW)- Dipole with Traps. This choke was made with #14 house wire and has a bit of an impedance mismatch so the antenna tuner is needed. His ZS6BKW multiband antenna took the original G5RV and adjusted the length of the radiators and ladder line matching HF End Fed Antenna EFHW-8010-1K 1000W 80-10m / NO TUNER NEEDED!! / 130 feet long. So that will be 32. You may operate these dipoles at up to 1,500 watts Find MFJ 17754 40/20M Dipole Antennas MFJ-17754 and get Free Standard Shipping on orders over $99 at DX Engineering! Total length of antenna in feet Open the dipole length calculator in a separate page. Most of the material I have read on the net about this type of antenna says the coax is used as the counterpoise but none discuss the coax length. > Brian, > > If your end fed antenna is actually a halfwave (which is what EFHW > means), the answer is no. The antenna is not symmetrical and there is no advantage to trying to shorten or lengthen both diagonal legs. Feb 28, 2017 · What makes an EFHW antenna multi-band? On 30 & 15, depending on the length this can be tricky, as 40m of wire is getting close to 1. No long counterpoise, radials or feedline required. The 1/2 size G5RV is a farce on the lower HF bands, as are most of the reduced dipole antenna arrangements so I wanted something that was a similar size but truly resonant so losses were kept to a minimum. It's cut to 64' in length with 12 THHN wire. It is a specially calculated length to provide as close as possible to the correct impedance, into the 9:1 unun transformer for the bands you want to operate on. Apr 05, 2019 · The last few years have seen a resurgence of interest in the end fed half-wave wire EFHW antenna. I stumbled across these antennas one day  Also very informative is a "Multiband & EFHW Antenna Presentation " by Steve Ellington N4LQ. Each network designed and tested to ensure great performance in a wide range of operating conditions. A piece of wire of almost any length can be used as an antenna on the HF bands. EFHW  The length of a half wave antenna is calculated using the following formula: L (ft) = 468 / f (freq in mhz). The basic formula for determining the length of a center fed, half-wave wire Dipole or Inverted Vee antenna is:. That is an end-fed, but very different then the half wave construction. Jan 04, 2017 · Part 2 – A 40 Meter EFHW with a “Radiator” wire and various length “Coax-as-Counterpoise” wires is analyzed – We will see that the common-mode current is almost always LARGER on the coax shield some distance away from the feedpoint, which is why the “counterpoise” radiates and is called “the other half of the antenna”. 160-6 METERS END-FED ANTENNA The ULTIMAX DXTREME end-fed antenna covering 1. If you are in a hurry you can throw it over a small tree. First Published: 14 August 2014 Last Update: 29  Full-wavelength antennas (loops) - multiply the chart dimensions by four (4) and change the overall length of the antenna by that amount. 1 81 results for antenna end fed Save antenna end fed to get e-mail alerts and updates on your eBay Feed. HF End Fed Antenna 1000W 80-10m / Ham Antenna with 9:1 UNUN / 73 Field Day 2018, travel back to Omaha from Virginia. It uses a 49:1 transformer for Apr 06, 2020 · Let's examine the EFHW in more Detail! Let's talk about the EFHW (End-Fed Half-Wave) Antenna some more. Thus 8, 16, 32, 68 lengths are ruled out. EFHW featured in "Stealth Working 160M From a Small Lot (and Larger Ones Too) short antenna so it looks longer to –Length of guys to first insulator Oct 20, 2018 · End Fed Half Wave (EFHW) Antenna Upgrade Part 1 - The Matching Transformer For several years the EF-10/20/40 MKII “EndFedz “ has been my main station antenna for HF. I am a coffee snob too, but that is another story. S; Stealth #18 AWG black wire. The antenna length is 31. The distance between one point to another adjacent point in a wave is known as the wavelength. Obviously, an EFHW antenna has a "half-wave" length only at one specific frequency. End-fed wire antennas are a different beast. All you need to do is enter the desired resonant (center) frequency in the form below, then click "Calculate". I did not have any grounding (our counter-poise) at the feed-point nor did I have any current balun or RF choke anywhere in the feed-line. It has become nearly as popular as the famous G5RV after all! It gives full HF coverage with no tuner needed on most frequencies, you do not need a long counterpoise, radials or feedline, it EndFed 1/2 Wave 800W 80M-10M Wire Antenna EndFed 1/2 Wave 800W 80M-10M Wire Antenna FULL HF Coverage, no tuner needed on most frequencies. Feb 08, 2017 · The reason your antenna was a lot less finicky with a bit of coax is that the EFHW antenna requires a return path for the RF field. 48 feet) and 65. feed line length. A half-wave antenna is a resonant radiating element with an electrical length of one half-wave. The antenna's length (approx. Resources listed under antenna category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. Now, I want to make my "pro" model. Length can be adjusted by looping free end over to shorten antenna wire. com. I'm building a 49:1 transformer for a 80mtr EFHW antenna. A centre feed gives around 70Ω. But I am running it for 10-80m. Due to high impedance feed point; the antenna is less height dependent. But performance is down about 8-12db on a dipole on The theory of the antenna length is to make the antenna non-resonant on any amateur band so that the impedance at the antenna side of the matching unit is in the range of 200-600 ohms and when divided by 9 will be in the range of your transceiver antenna tuner. The EndFed 40 m to 6 m Antenna is arguably one of the best field antenna choices you can make for QRP ops and is especially well matched with the KX3, FT-817, the KX1, and any other QRP rig with a tuner. The antenna in not a random length. EFHW feedline length. I saw photos that Steve WG0AT had posted on Facebook of his little EFHW, with the matching unit built into a dental floss container, for a light and compact solution. Like everything else, antennas come in many forms and flavors. Lengths are estimates. End fed half wave antenna length. Today, out on the parking lot, … The antenna calculator above uses this formula as a starting point to calculate wire lengths for the dipole. +/- 66' feet will give you a 40m half wave antenna and provide harmonics for 20m/15m/10m. If using coax in this manner, does the coax need to be a tuned length or will any length work? "EFHW" - the end-fed half wave antenna. Z of EFHW vs. It requires a high  An End Fed Half Wave Length Antenna is a variation of the much more common half wave length dipole antenna. NEW 300W PEP VERSION! Easy and fast installation. 5 Wave-Length wire on lowest band (130ft on. I wanted an antenna that small and lightweight! I'm confused about the requirements for a counterpoise for an end-fed wire antenna. The antenna is up 30 feet in the middle and the ends are at 26 feet. They are not a half-wavelength long, meaning that, if you choose the length of the radiator wisely, the impedance at the end of the wire will not be as high as the impedance of a half wavelength long wire. I am going to use 124. Any or all problems are in the counterpoise and feed system. May 05, 2019 · Portable 2m 144 MHz Coaxial Dipole Antenna Andrew VK1AD / 10/02/2018 A homebrew 2m 144. Dipoles need to be half a wavelength long, locating these long antennas can be an issue, especially when we are aiming for the 80 metre band or lower. The W1SFR End Fed 35’ Random Wire Antenna with 9:1 UnUn What is a random wire antenna and how does it work? The term “random” infers that you can use any length of wire you want as an antenna, while that basic fact is true, there are some practical considerations. An example of that would be testing both antennas on my Mirage BD35 amp I travel with and the SignalStuff antenna allows connection to a local Winlink node while the SR320A does not connect. Note that the shorter length eliminates the need for a tuner on 17m. This results from a variety of factors associated with the fact that the current is flowing in a wire of finite length. This seemed odd as the EFHW was averaging 10 to 12 spots per cycle. I heard and read balun designs were good. One of the cautions you sometimes see in discussions of the end-fed antenna are "avoid multiples of a half wave. If you cannot get the antenna to tune, check the wiring first. 5MHz to 50MHz. It has a constant impedance transformation ratio of 49:1 from 3. HF Antennas Especially stealth models for those in an HOA By Dave Land Single band antenna when fed by coax •Should not be a resonant length •70 or 140 ft • Length of wire resonates the antenna – Very little current near the ends of a wire – Bending simply distorts the pattern a bit (mostly fills in nulls) • Bend it at one or both ends – Has least effect on pattern or efficiency • Bend it anywhere along its length – A bit more effect on pattern (fills nulls) Fitting Full-Size Tom, I have used a 135-foot or so end fed No. I have inserted two additional links for coverage on 17m and 30m. My new discovery convinced me to buy a MyAntennas 80-10 EFHW. Steve Nichols G0KYA Contents 1. And I’m going to keep this VERY simple It`s no secret that weather events are getting stronger -- the EFHW makes a great emergency back-up for your regular antenna. Jan 16, 2019 · ration Unun EFHW antenna can be tuned by adjusting length of the antenna. Mast heights and spacing can be easily adjusted in the model. �I understand that it's needed, but I don't understand what the requirements are. On Sunday, 3rd of June, I headed of early to activate the White Dam Conservation Park VKFF-1122. What are the advantages and disadvantages of the end-fed half wave antenna? I would mention first its ease of installation. The 16ga wire is very stealthy and has a tensile strength of ~100lb (45kg) so you have to make sure that  The length doesn't matter much. The purpose of this group is to explore the use of an end fed half wave antenna. 75. Your PayPal receipt is your confirmation that we have received … 49:1 Unun. Measure SWR exceeding 1. There is obviously some symbiotic interaction occurring between the wire, the tower and the yagi on it. Listed under the Antennas/End-Fed/End Fed Half Wave Antenna category that is about EFHW End Fed Halfwave Antenna. It typically is configured as an inverted L for 160 meters, using a small BC variable in series at the feedpoint to tune for lowest SWR (using only 100 watts). ] I bought the LNR EFT-10/20/40 trail-friendly end-fed halfwave (EFHW) antenna about a year and a half ago, after seeing one at Field Day. The Hertz antenna is an antenna with an electrical length of a half wavelength at its resonant frequency. Are there any benefits of using two torroids for QRP operating? Regards Peter. 18 wire for numerous portable operations with great success. S Stealth #18 AWG black wire Description EFHW-8010P- 200W Portable or Stationary Multi-Band End Fed Half Wave Antenna This is a 200W version of popular EFHW-8010 End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. Reflection coefficient vs. May 25, 2016 · I’ve made some progress on the EFHW antenna since my last post here on AmateurRadio. An overview and where it all started 2. Your PayPal receipt is your confirmation that we have … The physical length of any HF antenna is critical to achieving resonance and good performance on a particular band. 2 The antenna itself works just as well as any other wire of similar height and length. It can be fed at the low impedance point at the centre as a half wave dipole or fed at the high impedance point at either end. These dimensions were derived from modelling the antenna in EZNEC. The versatile end-fed wire. A VNA confirms this antenna tunes well to the entire 2m band when shortened from its maximum length to the 40 inches shown above. Length of counterpoise should be a minimum of 30-40 feet but not the same length of the antenna wire. The end fed half wave antenna presents a large impedance to your rig, so this impedance must be stepped down to a more useful   The first relies on the fact that from the end of the antenna a length of wire on or two half-waves long looks very similar. Unfortunately it can be hard to tell just what "proper" means. Dec 15, 2018 · Wire length ~130 feet Power Handling: 200W I. 1 metres (65. May 06, 2014 · My antenna solves the problems of my other EFHW antennas by introducing breaks in the wire where I can add or remove length to get on other bands. The G0KYA EFHW – an end-fed half wave monoband HF antenna, plus two multiband versions (New!) A practical, cheap monoband or multiband (new!) vertical antenna that is great for DX and very cheap to build. C. 2 MHz vertical 1/2 wave Coaxial Dipole antenna project for your home QTH, SOTA, portable field operations/WICEN exercises or the emergency 2m Go-box. The antenna has a full 300kHz bandwidth on 80m between 3:1 SWR points. Add Review × Sep 14, 2018 · The stock FT1D antenna is shown for comparison. It's also possible to  At multiples of half wavelengths of the transmit frequency the impedance is so high that tuners in most rigs often can't match it. 05λcounterpoise •Transformer is a toroid with N:1 turns between primary and secondary •Capacitor should be in range to resonate at the operating frequency with the maybe better. Coax feed line between the impedance matching unit and the radio is a 2 metre length of RG58AU. This may be required if using the antenna as a horizontal end fed dipole with a short length of coax. Center support is a fiberglass mast. Antenna Hendricks 40m – 15m SOTA EFHW Tuner First, familiarize yourself with the parts and check for all the components. However, it needs a tuner to get the SWR low enough on some bands. 5 metre squid pole, again as an inverted V. The result was gratifying - so  Wire Antenna Calculator. So, a "multi-band end-fed half-wave" antenna is actually a bit of a misnomer A "half-wavelength" radiator has a high impedance ( = high voltage, low current) at the feedpoint. In other words 100% homebrew. Playing with the antenna analysis program EZNEC, I modeled these end fed antennas including the complicated tower and elevated cabled trays from the tower to an antenna patching area and all the cables that attach to the tower system. High current, low voltage at center; low current high voltage at ends. The following program will calculate the lengths needed to construct several popular wire antennas. [Disclaimer: Any misadventures I have had with this antenna were purely my fault and, in no way, reflect on LNR and their excellent product. Compare  As a super simplistic aerial option the End Fed Half Wave (EFHW) aerial just about takes the biscuit. We chose EIRP to avoid any cables possibly conducting common mode currents. While functioning as a full-size dipole on 20-meters, it's also an ultra-efficient end-loaded dipole on 40-meters. These are made by tying fishing snap swivels onto the wire (we're using #26 PolyStealth wire here) and soldering a mini-bullet connector as the mate. ó , kdyh kdg \rxu pxowledqg hqg ihg dqwhqqd lqvwdoohg khuh lq 6lqjdsruh iru d ihz zhhnv qrz dqg dp yhu\ sohdvhg , xvhg wkh zluh iurp p\ suhylrxv dqwhqqd zklfk lv ihhw orqj ,w zrunv ehdxwlixoo\ , kdyh lw The longer length results in a lower frequency of resonance and the shorter length results in resonance at a higher frequency. The first relies on the fact that from the end of the antenna a length of wire on or two half-waves long looks very similar. Nov 11, 2012 · Total length is around 32 meters which is the max I can put up, it still gives me pretty good performance and over 150 kHz bandwidth (SWR < 1:2) on 80m. efhw antenna length

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