Efhw antenna counterpoise

Efhw antenna counterpoise. That makes the For 80m Band, this would be 4m of coax cable, so we recommend to use at least 5m of coax cable to feed any EFHW. But in some cases, depending on the length and position of the antenna, a ground connection or a counterpoise may help with a lower SWR. 05 wavelength wire inline with the half-wave radiator. One of the reasons for this is that most designs are for QRP antennas and not made to handle more than 5 – 10 W of power. wa7ark 26. An EFHW vertical is fast and easy to put up with a fiberglass mast, and gives a low radiation-angle antenna for WWFF / POTA park activations Photo is a 32 ft 20m EFHW vertical with 1:49 xfmr, on a 32 End-fed half-wave (EFHW) antennas provide a convenient way to move the coaxial feedpoint for a half-wave antenna from the center to one end. In general the EFHW antennas do not need a counterpoise or light up the coax with any measurable RF within their resonant areas but if you get out of band where the match is band they will light up the coax. No capacitor was After much research and testing, a new transformer design for End Fed Half Wave (EFHW) antennas has been achieved. A counterpoise should also help match the impedance of the antenna to that of the transceiver, in most cases 50 Ohm. For SOTA my favourite is a 40-10m doublet made with 22 gauge hookup wire, fed with 300 ohm ladder line Topics covered were the basics of EFHW antennas by Steve Yates AA5TB including lengths, design and installation of the antenna. Join the ham This is a 250W version of the popular EFHW-8010-1K+ End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. Surprisingly the random wire is winning, no counterpoise and 3-ft coax, with I believe a 50 something foot wire verse the 60 ft hw. If you choose the EFHW route you will EFHW-4010-1K-Plus™ Multi-Band End Fed Half Wave Antenna. 15 4 14. ) I could run a counterpoise wire away from the mast at an angle to the bottom of the garden & choke the coax at the base of the antenna. In the instructions of the Switched Longwire Tuner Plus (SLT +) of Pacific Antenna Switched Longwire Tuner - Plus - Pacific Antenna it is indicated that the counterpoise “should be 180° from active element direction” but in the instructions of the Sotabeams EFHW antennas might have elevated SWR readings on some bands due to the different position, height above ground or impact from nearby objects. No ground rod or counterpoise wire was used. 2:1 on 40M and 1:1 on 20, 15 and 10. If you trim/tune the EFHW for the SSB section of the 40m band, and are QRV near the resonant frequency, you won’t need an ATU. 6MHz, it’s fundamental 8th harmonic is 28. The radiation pattern on the fundamental frequency (where the antenna is 1/2 wavelength) will be similar to the same wire fed in the center as a dipole (but this is not the case on harmonics). If this a commercial antenna, you should be able to contact the manufacturer for advice. End-Fed Half-Wave. One thing we must keep in mind is that, since the wires are of unequal length, the antenna is NOT BALANCED and therefore any “voltage balun” will fail to match the load, will fail to isolate the I own two of the MyAntennas, the EFHW-8010-2K and the EFHW-16040-2K. Unlike many END FED antennas on the market, this one does not require the For the antenna I cut about 10m of wire for the 20m band and just 1m for the counterpoise. In Here is a sure fire way to make end fed half wave antennas fed with a 50 ohm coupler work - without long radials, elaborate grounds Now remove the resistor from tuner and connect the antenna. To help new hams prepare for the exciting world of HF opening up during Cycle 25, ARRL has partnered with HF Kits to bring you this easy-to-build four-band antenna kit: an end-fed half 80-10 end-fed half-wave antenna with 49:1 unun Many hams in the club have asked about this antenna, because it’s been such a good perform-er during Field Day, a Special Event Station, and at the 76ers Picnic. I used my own wire which is smaller than what he sends with the package because my wire is harder to see by the HOA cops! It is mounted 30ft at each end and after playing with a counterpoise the only band with The antenna works also on multiple harmonics, not exactly, but good enough, albeit with additional lobes. There are some Band specific windings for EFHW with a T50-6 Typical EFHW antenna lengths and bands to expect. But they will produce contacts, as any wire antenna of similar length and height will. An EFHW vertical is fast and easy to put up with a fiberglass mast, and gives a low radiation-angle antenna for WWFF / POTA park activations Photo is a 32 ft 20m EFHW vertical with 1:49 xfmr, on a 32 EFHW-7510-2K-Plus, 2000W Multi-Band End Fed Half Wave Antenna. This not only acts as counterpoise. The short, so-called counterpoise conductor of an "end-fed" antenna in reality means that this configuration is an off-center-fed dipole, as stated in the graphic. 8MHz but due to the Velocity of wave propagation on copper wire (with insulation) and “end effect” ( first and last half-wave sections), the real 8th harmonic is above 28. Portable operation Current Antenna Selection. 5m wire hanging down from a 6m tall glass fiber pole, fed by a 49:1 coupler and some meter of coax. Improved version of the EFHW-7510-2K, now with three large cores, 3-inch diameter, featuring just 0. While my “hand-test” reveals measureable sensitivty near the matchbox, running my hand down the feedline to the antenna analyzer has a very small effect. With the EFHW the earth (or a counterpoise) is still important, but not quite as crucial. End-fed, half-wave antennas (EFHWs) are a Project by Frank Bontenbal, PA2DKW Process photos by Bob Inderbitzen, NQ1R Please note: This kit is available from ARRL. The impedance will vary wildly from band to band, so the step up transformer won't be a perfect match. A NEC model that includes the transformer helix helps demystify the end-fed half-wave (EFHW) dipole antenna using the autotransformer as impedance converter. When I use our RV, I use a 31ft. But what about operation above 20 meters in single band and multi band EFHW antennas? Let's find out!While discussing the results of that experiment with other hams, ARRL EFHW (hfkits. Those can be individually launched and then connected to the center insulator/coax and hoisted up rather easily, even as an inverted Vee if only 1 support is available. 5 KW plus 160-10 meter operation. of coax from the box, What is an End Fed Half Wave (EFHW) Antenna? •An EFHW is a wire antenna resonant on its ƛ/2 frequency and harmonics •A 40M EFHW is resonant on 40/20/15/10M •The end impedance is ~2500Ω and varies a bit due to wire orientation •To get proper resonance on the harmonics a coil and capacitor are required •A counterpoise is required. There are quite a lot antennas that do a lot better job when providing a counterpoise. That means, you need an antenna that is one half wavelength for each frequency that you wish to work. The EFHW can be deployed in a miriad of topologies, this article goes on to explore three popular practical means of feeding such a dipole. . It has an SO 239 connector for the antenna coaxial cable. 47 RMS amps in this example. What is an Efhw Antenna? An EFHW (End-Fed Half-Wave) Antenna is a type of radio antenna commonly used in amateur radio. Numerous web sites reveal the coil and series capacitor of these antennas. Extra Wire for Counterpoise: Even after building your antenna, you'll have leftover wire to use as a counterpoise, enhancing performance of the EFHW; Efficient Performance: Paired with a 49:1 transformer, this antenna offers low SWR (no tuner required Maybe you should revise some of your statements in this blog post because they reflect great misunderstanding how most multiband antennas work including EFHW end fed antenna. Without an earth the antenna will try and use the coax as the return path. All contacts made using EFHW 8010 antenna in an inverted L configuration at 50 feet vertical 80 feet horizontal sloping to 20 feet above ground. This article will explain my findings and reasons for constructing it the way I did. Jackite pole with this antenna. SWR was about 1. For this I have a nanoVNA running 10 segment sweeps on the UnUn with two gator clips on each end. 5dB (~30% loss). 5 Band EFHW Antenna 80m-10m | 49:1 End Fed Half Wave - YouTube Be sure to In some cases the antenna will be made longer then needed on purpose and you are expected to trim it to get the best SWR for your set up and usage. There are some About Counterpoise; About SWR; About Grounding; Shop. So far, I built a “49:1” transformer with 3:22 ratio turns and a 100pF capacitor. 05 wave lengths long (ft = 49. The original radio antennas were monopoles or center-fed dipoles. Explore the complexities of End-Fed Half-Wave (EFHW) antennas, their impedance challenges, and configurations for efficient multi-band performance. I recently tried assembling a EFHW kit, and some problems came up in testing. Reading about the best counterpoise installation I find that there are opposing recommendations. FULL HF Coverage, no tuner needed on most frequencies. L is the length of the antenna (feet) f is the frequency (MHz) To calculate the length of an EFHW antenna, divide 468 by the frequency in MHz. It does not require an extensive ground like a big ferrous vehicle body, only a short counterpoise wire. Various dipoles vs. a resonant half-wave will reduce the Laurence, WA2TLY, is asking some questions about a few aspects of the EFHW 80-10 antenna, Why they are there and what they are for? Watch to learn more. It’s what one finds in end-fed VHF and UHF antenna systems from Diamond Antenna and others. Portable operation Versatile Design: With this kit, you can easily create a 20-meter or 40-meter EFHW antenna. 05 lambda (about 13 feet) long. No wire counterpoise is used to reproduce the SOTA setup. DJ5REs U01 Antenna – A linked EFHW for NVIS use, that covers more bands by „connecting“ or „disconnecting“ wire length. f. Unlike many END FED antennas on the market, this one does not require The QRPGuys Micro 40-15m EFHW Tuner/Antenna is the smallest and lightest tuner/swr indicator/antenna we produce. (And subscribe to his channel!) How to purchase. You should be good for 40, 20, 15 & 10 Meters. Random length gave me more troubles and I do not like those. There are three types of antenna feeds in popular use: 1) Third, any end-fed half-wave antenna will require a From IEEE-145-1993-R2004 2. NOTE: Antennas and transmitters both are two-terminal devices, and will supply/radiate almost no energy if only one of their terminals is connected. 05 wavelength on lowest band from memory) down the coax from the 49:1, that is sufficient for the "counterpoise" and the return currents. As with all antennas, the EFHW is a compromise. Thank you. Of end-feds and feed-lines. 86 counterpoise. EFHW-4010-2K-Plus, 2000W Multi-Band End Fed Half Wave Antenna. Either use a "counterpoise" at least 0. This is my first time making an UnUn and EFHW kit. (Counterpoise) In the case of the End Fed antenna, you can simply make . No, what I modeled is not appropriate for a 1/2-wavelength dipole or even a classic 1/2-wavelength hunk of wire free space. From IEEE-145-1993-R2004 2. The very best web page I have seen so far includes real test data comparing center-feed dipoles vs EFHWs with and without counterpoise: Of course if the EFHW antenna match circuit is (by good luck) already perfectly where it needs to be then any length EFHW antennas might have elevated SWR readings on some bands due to the different position, height above ground or impact from nearby objects. Not sure where your antenna will mount and would need more info Review Summary For : MyAntennas EFHW-4010-HP; Reviews: 4 MSRP: 150; Description: EFHW-4010-HP 1500W Multi-Band End Fed Half Wave Antenna This is an End-Fed Half-Wave (EFHW*) antenna for 40/20/15/10m bands. I have found wire antennas to In the EFHW, the counterpoise is essentially turning it into an OCFD. Many were just as amazed by its seeming simplicity and ease-of-installation, and wanted to build one for themselves, es- With very little counterpoise, the antenna is being fed at a high impedance point so a rather large impedance step-up is employed. This brought the SWR down to about 2:1. 10 meters is a compromise for better SWR elsewhere. 05 wavelength section added and free space presents very high impedance to the other end of the 0. Most importantly, you don’t need any counterpoise for this antenna, or at least only a very small one (0. I decided to just use a few jumper wires chained together to create a counterpoise, with a total length of about four For the past couple of weeks, I’ve been playing with end-fed wire antennas. 5 dB Insertion loss! NO counterpoise is needed! (Grounding recommended*) Frequency coverage: 7-30MHz; Resonant on 40/20/15/10m; Wire length ~63 feet ; Then a CMC is placed along the coax to stop RF on the shield but give the EFHW antenna some short length for a counterpoise, since physics says it needs one. Then I ran some tests with my vna and a 2525 ohms resistor. The transformer feed variety may be broadband and, depending upon its construction may be Versatile Design: With this kit, you can easily create a 20-meter or 40-meter EFHW antenna. Josef Most importantly, you don’t need any counterpoise for this antenna, or at least only a very small one (0. To solve the impedance problem, a simple L-C antenna matching network can be inserted between the feed line and the half wave antenna wire. The End Fed Half Wave (EFHW) is one of the most popular antennas and is currently proving to be one of the best options for new Hams and those that I am using a QRPGuys EFHW Mini-Tuner with my FT-817. 9 reviews for EFHW-4010-P. 05 wavelength counterpoise for an EFHW (just 1 meter on the 20m band), so most of that run down the garden would be guy rope! Design an End-Fed Half-Wave (EFHW) antenna, in either an inverted-L or inverted-Vee form, using a single main support. Fast Setup and takedown. , EFHW) AND the counterpoise. Its best to use a good common mode choke balun in the feedline near the antenna, maybe 5 to 20ft down the coax from the matching transformer. I used it recently as the 40-10 EFHW with the antenna as an inverted V using the Jackkite, then later as an end fed sloper. These mismatch losses occur with the following This is an End-Fed Half-Wave antenna (EFHW) transformer covering 80/10m amateur bands or any frequency in between. Learn about the Here's a link to WA7ARK's analysis of a 40-10M EFHW antenna vs counterpoise length that sums it up nicely. com 40415 Chancey Rd, STE 105 Zephyrhills, FL 33542 USA There are better antenna compromises out there than an EFHW, and keep in mind, it's only a half wave on one band. Improved version of the EFHW-4010-2K, now with three large cores, 3-inch diameter, featuring just 0. This was a quick test, but interesting nonetheless. This gave an SWR of about 3:1. This is a multiband antenna without the need for any tuner (which is the best type of antenna). Another advantage of the EFHW is that unlike most QRP antenna couplers, there are no variable capacitors used that typically can’t handle much power. The 6 foot RG316 cable also acts as a counterpoise, conforming very well to the suggested 0. to switch over the wire antenna from EFHW transformer secondary to the coax feed & capacitor of 270pF / 3kV (doorknob type, this type is able to withstand Currently doing a similar thing between a new EFHW and my standard EFRW. 1 has the advantage of working without ground or counterpoise The last few years have seen a resurgence of interest in the end fed half-wave wire EFHW antenna. Before I get into the nitty-gritty details, let me first make a distinction between end-fed half-wave antennas, such as the ones sold by LNR Precision and end-fed wires that use some kind of tuning to achieve a 50 Ω output impedance. But the noise level on receive is very high. I just let the I am currently using an end-fed wire of about 23 m. QRP EFHW antennas. Jonathan is selling his antenna kits on eBay–click here to check it out. I kept it simple. I then raised the end of the antenna and tied it to a convenient bush. I used about 5 feet of counterpoise with ~ 25′ of RG8X feedline. The radiation pattern on the fundamental frequency (where the antenna is 1/2 wavelength) will be similar to the same wire fed in the center as a dipole (but this is not the case on harmonics Then a CMC is placed along the coax to stop RF on the shield but give the EFHW antenna some short length for a counterpoise, since physics says it needs one. In Figure 2A, the ground attachment screw of the transformer is not connected and Portable or Stationary Multi-Band End Fed Half Wave Antenna. These antennas can be mounted horizontally, vertically, or as a sloper. I like sloper the best. This would require a good ground as counterpoise, but that was not a problem, as I had provided this already for the EFHW feedpoint by a copper strip of 25mm wide, ground rod and nets. A good way to minimize this is to create a counter-capacity. The original assembly instructions are available from the manufacturer, HF Kits. Of course, there’s no need to keep an EFHW all vertical, you could hang part of it horizontal, or Run a 28 1/2 foot wire sloper with a 17 foot counterpoise, directly to the G-90! The radio will tune it!! Reply reply This includes dipoles, doublets, linked dipoles, EFHW antennas. EFHW stands for “End Fed Half wave” and was first introduced way back in 1927 by the Austrian radio amateur, Dr. 05 Lambda, more on this later). I have one running East/West and the other North/South. It is rated at 5 watts continuous, 10 watts PEP, and utilizes the N7VE led SWR indicator and attaches directly to the transceiver’s female BNC connector. To explore parameter space a little, I modeled a couple of lengths for the counterpoise EFHW Counterpoise Current flowing into the antenna's end must be equaled, at that end point, by the same amount of current flowing into a ground or counterpoise of some type. However, an end fed half wave antenna often has quite high impedance, creating a miss match with the usual transceiver impedance of 50 ohms. The final rebuilt EFHW antenna comprises a 49:1 conventional transformer (per method 3). Antenna’s that require a counterpoise. This is a 200W version of the popular EFHW-4010 End-Fed Half-Wave (EFHW*) antenna for 40/20/15/ and 10m bands. e. I wonder what would be the next big mystery about the EFHW-8010 antenna. Categories Antennas Tags 4nec2, autotransformer, counterpoise, dipole, EFHW, end-fed, feedline, FULL HF Coverage, no tuner needed on most frequencies. End-Fed Horizontal Wires(EFHW) cover multiple bands with-ou At the extreme end of this is the End-Fed Half Wave (EFHW) antenna, where the counterpoise is only a foot or two long, and the impedance is on the order of 1600~2400Ώ. There are quite a few convincing and persuasive arguments on-line concerning counterpoise use. Reply reply Ironring1 • EFHW vertical is just a dipole oriented vertically, fed at one end. The EFHW 49:1 Autotransformer Kit is suitable for construction of an efficient End Fed Half Wave Antenna for the 3. End-fed half-wave (EFHW) antennas provide a convenient way to move the coaxial feedpoint for a half-wave antenna from the center to one end. The model showed otherwise when all the parameters were considered. Of course, you’ll need some wire for your radiator and/or counterpoise. A lot of literature seems to suggest that you only need 0. This article presents a redesign of the transformer to address many of the issues that give rise to poor performance, and bench measurement of the There are better antenna compromises out there than an EFHW, and keep in mind, it's only a half wave on one band. NO counterpoise needed! Grounding of cable at the entrance to the home is recommended; Frequency coverage: 7 MANUAL: ENDFEDZ 40-10-KW EFHW 1KW ICAS ANTENNA The EFHW (End-Fed Half-Wave) antenna is one of amateur radio’s oldest antenna designs. 1:1 current balun built into the transformer to keep common mode current off the coax and out of your shack. The best way to resolve this is to fit a choke, such as 10 turns of RG213 on a four EFHW HT antenna functions without additional counterpoise; Adding 0. The price is $29. Voltage and current distribution and the issues this presents, the minimum counterpoise, impedances and turns ratios of end fed impedance transformers. an Odd Quarter Wave-Length of your target band 186 ft / 16. Unlike many END FED antennas on the market, Leopoldo, YV6ENB, is asking what is the recommended counterpoint length and random wire arrangement for EFHW antenna? Watch to learn more about the different If you purchase this EFHW kit, I’d encourage you to watch his build. The three terminal feed device and Adam includes instructions for building an EFHW with a counterpoise, without a counterpoise, or a random wire antenna. 65m) and counterpoise (66cm) from the above calculator. 5 ( 80m ) to 30MHz ( 10m ) bands. com. Featuring an optimized MEF-130-LP transformer with an average insertion loss of only -0. Rugged weather-resistant 50-Ohm matching network. There are three types of antenna feeds in popular use: 1) transformer feed, 2) L-matching network feed, and 3) Zepp. This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. The KX3 ATU achieves a “reasonable” tune on it with the help of a 1:4 balun and a random counterpoise. The physics says that the radiated signal has to have something to push against. The antenna length was mentioned as 20 m, which was half wave at the lowest frequency. It is resonant Half wave on 40m (7MHz A half wavelength is just that. If balun is installed high above the ground, all that has Grounding per NEC is always recommended but an EFHW does not require any ground and adding ground or counterpoise wires will probably not improve anything. one with 0. My Account; Cart; Checkout; Contact; F. The absorption SWR bridge insures that the worst case match the transceiver sees is 2:1 while I never use the antenna wire as one of the guys, which is why I think all my wire antennas have been so reliable after so many years. Adding 0. 58MHz the antenna (main wire) needs to be lambda/2 at 3. The binding How efficient is an end-fed half-wave antenna? An end-fed half-wave antenna can be efficient, especially when properly matched and with a suitable counterpoise. I’ve posted about end-fed, half-wave antennas before, but until this weekend, I’d never built one. Stay tuned for a more thorough test in the near future with Ah yes- The nearly century old controversy about the EFHW and counterpoise rises again. Counterpoises are commonly added to shunt common mode reflections when operating You may find a lot of debate about using a counterpoise with an EFHW antenna. Then a CMC is placed along the coax to stop RF on the shield but give the EFHW antenna some short length for a counterpoise, since physics says it needs one. EFHW HT antenna functions without additional counterpoise; A very simple antenna to make, deploy and use is an end fed wire antenna. In spite of How to create a counterpoise for an EFHW antenna is hotly debated. Balun and counterpoise in green. A viewer asks: Is it correct to say that a counterpoise is not needed for an End Fed Half Wave (EFHW) antenna? Dave and I tackle this somewhat contentious su EFHW-4010P antenna only, EFHW-4010P with 50ft of RG8X coaxial cable, EFHW-4010P with 100ft of RG8X coaxial cable . Therefor it has a antenna. Here is an image of the 64:1 impedance The final tests with EFHW antennas for 80-10 m then only confirmed the well-known: Due to the complex and non-linear permeability of the ferrite material and the non-constant impedance of the EFHW antennas in the range of 80-10 m, which unfortunately do not neutralize each other, result mismatch losses. Join the ham The Par EndFedz® End Fed Half-Wave ("EFHW") antennas are like a full length half wave dipole antenna, but with an important difference. I am constantly working on new antenna designs. I know that. I have a 10 foot coax cable leading out of my house to a lightning surge protector (MFJ-270) outside of my house, and a 25 foot coax cable leading up to the peak of my house, where the EFHW antenna stretches out 66 feet to the back of my backyard, Some sources suggest using a counterpoise wire, while others say it's not necessary. Too Dense to launch an EFHW Antenna. I attached a counterpoise to the gnd connection and was able to work 80 meter successfully to folks in the Pacific Northwest on 10 Watts. 2 thoughts on “EFHW A viewer asks: Is it correct to say that a counterpoise is not needed for an End Fed Half Wave (EFHW) antenna? Dave and I tackle this somewhat contentious su I recently posted a blog claiming that a capacitor in the primary of the matching transformer is not needed for end fed half wave (EFHW) antennas operating on 20 meters and below. Attach Antenna wire to antenna frame winder (See Video for Sequence) **TUNE ANTENNA TO THE MIDDLE OF THE GENERAL PORTION OF 40M BAND 7. Regarding the counterpoise, an EFHW would not use "ground" as a counterpoise, rather, since an EFHW has a high impedance at the feed-point compared to the low impedance output of modern radios, and the low impedance of coax, both usually 50 Ohm, an impedance transformation must be done at the feed-point; this can be done a couple of ways. Between the gator clips sit one 100 ohm resistor It was published in Karl Rothammel’s antenna book, DM2ABK, Y21BK. By using traps, the antenna works on all three bands with no operator interaction. 2 EFHW-7510-2K-Plus Multiband End Fed Half Wave Antenna Improved version of the EFHW-7510-2K, now with (3) three large cores, 3-inch diameter, featuring just 0. Stainless Hardware, UV resistant materials throughout. If can get access to one try a antenna analyzer to see how the SWR varies with frequencies. The required Antenna wire length required is approximately a half wave length at the lowest frequency, i. When lying the feeding line Special Variants. What is the most directional antenna? Yagi-Uda antennas are known for their directionality, making them a popular choice for applications where focused communication is needed. Several ways exist to bring the wire’s high impedance feedpoint closer to the desired 50 ohms, including use of a 49:1 or 64:1 unun, which eliminates the need for an When choked properly, enough coax length to be the counterpoise or a counter poise used, I get no common mode current / RFI in the shack. NOTE—The purpose of a counterpoise is to provide a relatively high For the antenna I cut about 10m of wire for the 20m band and just 1m for the counterpoise. Can be installed Horizontal, sloping, vertical, inverted "V" and inverted "L" Counterpoise can be colinear with the antenna or hanging down to shorten span. 95 plus a modest shipping fee. 4 RMS amps. 4 dB (~9% loss) compared to similar products on market with insertion loss as high as -1. In the image below you will see there is no counterpoise and no common mode choke at the bottom of End-Fed Halfwave Antennas (EFHA’s) seem to be experiencing a bit of a moment right now and we’ve heard questions about the need or desirability of grounds or counterpoise wires when using them. I've tried my EFHW in every conceivable orientation. I see people mounting the unun low to the ground and running a sloper. The result will be the length of the antenna in feet. Unlike many END FED antennas on the market, this one does not require the Antenna Tuner to operate. Our antennas are broad band transformers (multi-band EFHW) and they use the coax as a counterpoise for the antenna. a counterpoise should not be longer than a quarter-wave. ends up anywhere (c)2016 - no1pc, jim aspinwall . 237. EFHW exploration – Part 1: basic EFHW explored the basic half wave dipole driven by an integral source as a means of understanding that component of a bigger antenna system. A transformer was wound on a FT50-43 toroid with 3 bifilar turns followed by another 31 turns of #26 enameled magnetic wire. Extra Wire for Counterpoise: Even after building your antenna, you'll have leftover wire to use as a counterpoise, enhancing performance of the EFHW; Efficient Performance: Paired with a 49:1 transformer, this antenna offers low SWR (no tuner required Both the coiled counterpoise wire and antenna wire can be seen here. A couple of months ago, I ran across a design rated at 100 W. So a 100 watt transmitter fed into a 34 ohm antenna will result in ~1. When not it use, the 9:1 is disconnected and the antenna/counterpoise are clipped together DIY End Fed Half Wave Antenna Kit for 10-15-20-40-Meters ARRL and HF Kits offer a 4-band antenna kit: End Fed Half Wavelength Antenna The advantage of an EFHW is the ease of construction, it’s versatility in a variety of installation An End Fed Half Wave (EFHW) antenna for operation on 20, 30 and 40 meters was built for SOTA operation. I am not a big fan of the 49:1 Un-Un fad that a lot of new hams are falling for. Here is the list of possible problems you might have experienced with EFHW antenna models: 1. I set up an EFHW for field day using a similar transformer with 25 ft. We use cookies to optimize our website and our service. The only better antenna, especially RX, I use is my mosely ta-63-n. Made a few QSO’s on 40 and 20, band conditions addition to the connections to the antenna wire and coax, the instructions suggest MyAntennas End-Fed Half-Wave Antenna for 80 – 10 Meters Bottom Line The EFHW-8010-1K provides an easy-to-deploy antenna that can be operated on all HF bands, except 60 meters, with a low enough SWR to be used without an antenna tuner on most bands. For example, fan dipoles. Hello, I’m trying to build my first efhw antenna. Originally counterpoise wire can be up to ¼-wavelength long and should be approximately under the antenna wire with the far end unconnected. 5 feet and get the following (red is longer wire, green is shorter wire): Final update: Antenna is in its "final" state, spliced with PosiLock connector and crimped with an aluminum sleeve at the end. The article about “counterpoise” by Owen Duffy, VK2OMD ex VK1MD addresses many issues with the term. The Antenna Tuner is a 1977 HeathKit HFT-9, a small QRP size tuner of the Cap-Coil-Cap double"L" design. 05 wavelength should be added to the ground connection of the transformer box. 05 wavelength wire to EFHW antenna; Simulating the end-fed half-wave (EFHW) dipole antenna; Categories Antennas Tags autotransformer, EFHW, end-fed, ferrite, transformer. The design seemed relatively simple to build, requiring only a single toroid and a EFHW should also have a common mode choke about 8 ft (0. As you can see I fit a full sized 80m EFHW (End Fed half wave) antenna measured at 130ft. I think giving the antenna 20ft or so of coax as a counterpoise before the choke might help if you ever use the antenna out of band or for In the previous post, LNR EF-10/20/40 Examination, the topic of counterpoise occurs often. 55 Fundamental operation at bottom end of 80 metres 2 7. If anyone has experience setting up an end-fed wire antenna inside an apartment or has any tips or advice, I would greatly appreciate it. But even setup 7ft ASL like an NVIS I was able to make 1k mile contacts at 59 with 100w. These antennas — at least supposedly — involve feeding only one element at its extrema, using a transformer "matchbox" to compensate for the impedance at that otherwise unlikely feedpoint. When you have three counterpoise radials, the maximum current in each radial is 1/3 of the antenna current or ~0. wa7ark 27 Move the first SWR null to 75m The EFHW-8010 has the The Par EndFedz® End Fed Half-Wave ("EFHW") antennas are like a full length half wave dipole antenna, but with an important difference. Wire does hit and lay on edge of garage roof before laying on house pitched roof. End-Fed Horizontal Wires(EFHW) cover multiple bands with-ou MANUAL: ENDFEDZ ALLBAND-KW 80-10 EFHW 1KW ICAS ANTENNA The EFHW (End-Fed Half-Wave) antenna is one of amateur radio’s oldest antenna designs. But, if you want to do CW as well [without an ATU] it would be best to use an AA to EFHW HT antenna functions without additional counterpoise; Adding 0. connection of the aerial to an intermediate circuit as seen in Fig. To counterpoise or not to counterpoise. 65 Would need Antenna tuner to operate between 10. Tie both primary and secondary of the UnUn to the shield of the coax cable and put a good common mode choke about 13 feet away from the transformer. Enjoy your EFHW Antenna! I made 677 contacts that included working all 50 states between 15, 20, 40, 80 and even 36 contacts on 160 meters with antenna tuner. Featuring an optimized MEF-130-LP transformer Leopoldo, YV6ENB, is asking what is the recommended counterpoint length and random wire arrangement for EFHW antenna? Watch to learn more about the different For example, an EFHW-8010 antenna is half-wave resonant on 3. Pack and Go Antenna System. Without it, you will have RF in the shack, and the EFHW probably won't tune properly. The answer proposed by some is a three terminal feed device, and an additional short conductor to act as a so-called counterpoise (Duffy 2010). Also, do not listen to internet “experts” saying that some form of hanging counterpoise wire of 0. 2 thoughts on “EFHW Below is a photo of my QTH. To help new hams prepare for the exciting world of HF opening up during Cycle 25, ARRL has partnered with HF Kits to bring you this easy-to-build four-band antenna For 3. 5m counterpoise, and a 2µH load in series at 2m above the foot) would look something like this: 40m_efhw_vswr_chart 1252×502 37 KB. Used at MF and HF to provide an RF ground for an antenna“. Please read what I wrote. 5’ 1’ 40-20-10 ~67’ 2’ 80-40-20-10 ~134’ 4’ About Counterpoise; About SWR; About Grounding; Shop. But the question then becomes: what to do with the The MyAntennas EFHW-4010-1K is a really good antenna and requires no ground or radials for operation, except for grounding the coax per NEC for safety. The thicker the wire, the less inductance will result and that should keep the losses to a minimum as well. There was a 49:1 balun at the feedpoint. No “extra” counterpoise or other conductors required The Antenna Tuner will load an End Fed Long Wire effectively, especially if it is cut to aprox. Support Material. The transformer also uses the coaxial shield as a counterpoise, which as you know, is never good. (Counterpoise length and orientation will affect SWR. 05 wavelength With very little counterpoise, the antenna is being fed at a high impedance point so a rather large impedance step-up is employed. A. This is the page on the End-Fed Half-Wave antenna with a 49:1 transformer. This is an End-Fed Half-Wave (EFHW*) antenna for 40/20/15 and 10m bands. In the forest it can be cumbersome to unwind/erect versus say, 2 quarter wave dipole halves. An EFHW antenna benefits from a ground connection or counterpoise to establish a balanced antenna system and improve its performance. In addition to their capacitive loading, the "Bobs" also found the most important thing to make EFHW antennas work consistently on all bands was the need for a properly sized counterpoise as shown in the diagram s above. A system of conductors, elevated above and insulated from the ground, forming a lower system of conductors of an antenna. 05 wavelength wire. An end-fed half-wave (“EFHW”) antenna has a very high feedpoint impedance, often 1000 to 5000 ohms (depending on the diameter). Topics covered were the basics of EFHW antennas by Steve Yates AA5TB including lengths, design and installation of the antenna. Around S9 on all bands. The radiating element is a 31ft wire and is attached to one end of the transformer secondary. 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, zig-zag) Choosing a feed line choke or noise filter In my research on End Fed Half Wave (EFHW) antennas I found that nearly all have a capacitor in the primary (rig) side of the transformer. 2/MHz, m = 15/MHz) or connect the side opposite the antenna to the system ground In general the EFHW antennas do not need a counterpoise or light up the coax with any measurable RF within their resonant areas but if you get out of band where the match is band they will light up the coax. NOTE—The purpose of a counterpoise is to provide a relatively high. 1 and 10. I added a counterpoise and tuned the rest out figuring that the antenna didn’t change, and the coax was low loss and very short. 8MHz. Another advantage of the EFHW is In the above diagram you can see that the half wave portion of the antenna presents very high impedance to the 0. k. End-Fed Horizontal Wires(EFHW) cover multiple bands with-ou Bought an EFHW for 40, 20, 15 and 10 m from another ham. Will work on it a bit more over the winter. One way to get a better understanding of the interactions between the EFHW vertical section and the coax would be to model it in EZNEC (or 4NEC2 if thats your cup of tea). Different sources tell you to make the counterpoise wire different lengths, some even say that you don’t need a counterpoise. So, i needed an antenna that would allow to use these 3 bands in SOTA portable activity. Without counterpoise this will be the outside of the coax cable. 1 on 20m but a I like to have a length of coax before the choke to give the antenna some counterpoise. Toroid L1 L2 Comment T50-1 5 45 80m T50-6 3 23 Common ratio T50-6 1 7 10m T50-6 1 8 12m T50-6 1 or 2 9 15m T50-6 2 11 17m T50-6 2 15 20m T50-6 3 or 2 21 30m T50-6 3 31 40m Bands Antenna Length Counterpoise 20-10 ~33. David – December 13, 2017. Probably the most familiar is the end fed half wave antenna (EFHW) But random length or non-resonant end fed antennas are also popular and effective, especially for portable use. EFHW antennas possible problems. with the general thinking of getting as much sloped at a straight angle. Counterpoise While this is true for a parallel tuned circuit EFHW, a multiband end fed with a fixed capacitor across the primary is going to require a much longer counterpoise since there's going to be significantly more current flowing through the antenna. EFHW antennas F. No ground plane or counterpoise is needed. where the blue line shows the VSWR at the antenna. half-wave antennas. Become a Patron! Topics & Keywords. Rated 5 out of 5. Counterpoise Yes or Not? Salva - EA4HZK. Originally known as the “end-fed Zepp,” it was used by airships (known as “Zeppelins”) suspended from the fed end with the free end hanging loose. Actually, the 9:1 ratio is kind of magic, because 9 is the square of an integer. In my case I did not need a ground or counterpoise added. In the meantime ask Counterpoise. Works good with either. In addition to their capacitive loading, the "Bobs" also found the most important thing to make So a 100 watt transmitter fed into a 34 ohm antenna will result in ~1. I wonder if In some cases the antenna will be made longer then needed on purpose and you are expected to trim it to get the best SWR for your set up and usage. It radiates something useful as can be seen with RBN. It may be good enough for the transmitter's built-in tuner. I think it’s an excellent deal. And generally this current density is dominant near the base of the antenna and becomes less as you move away from the base. I decided to just use a few jumper wires An excellent receive antenna for the lower bands is the Beverage antenna. 1 Between CW and phone sections of 40 metres 3 10. Already having some experience with the EFHW antenna, i decided to build one for 40/30/20m. Your unun has integral numbers of turns in its primary (9 turns between the counterpoise and the radio tap) and an integral number of turns in the secondary (27 turns between the counterpoise and the antenna with 9 of the turns common to both primary and secondary). 6m) long #14 AWG XLPE black wire And yet another update. The coil can be configured as a a 49:1 Unun, 9:1 Unun, or 1:1 Balun. I plan to build mine with I’ve posted about end-fed, half-wave antennas before, but until this weekend, I’d never built one. My EFHW has better rx than my OCFD and has a lower noise floor. FREE Shipping in USA! BUY 2 or more with a group of friends and save even more! Need a high performance, multi-band, stealthy antenna system that is easy to setup This is a good example of an End Fed Half-Wave antenna that radiates almost as well as the reference dipole and seems to do so without regard to adding an appreciable counterpoise system. This type of antenna is designed for one principal amateur HF band, usually 80 meters or 40 meters, but typically displays VSWR minima on several higher bands, and can therefore be a good multi-band antenna. However, storing the wire set for one band and getting out the Hi all, I have just been looking through some linked EFHW designs both on the web and in this forum as I want to build a lightweight antenna to use with my little G106 radio. This is essentially the same as the Hendricks tuner unit, only without the case. Remember that, as with all antennas, the EFHW is a compromise – not particularly efficient at either short or long ranges. One example is the NR770HBNMO end-fed dual band mobile antenna and companion K515S Luggage Rack Mount groundless mount. 5 ft and 186 ft / 33 ft The entire antenna is #12 stranded insulated copper. There are quite a few convincing and persuasive arguments on-line concerning counterpoise use Both the coiled counterpoise wire and antenna wire can be seen here. For me this comes to a fine point in the "random wire" and also "end-fed half-wave" antenna guidance. A. Simulations suggest end-fed and center-fed half-wave dipoles share sensitivity to various feedline lengths, but in differing and manageable ways. How to create a counterpoise for an EFHW antenna is hotly debated. The high impedance, half Multibanding the EFHW antenna was easy by placing either manual links or LC traps. Or if you ground it with radials, it's turning into a 1/2 WL vertical/sloper/ whatever orientation you have it in. Both these antennas perform very well, and it's really nice to be able to switch between these two antennas on the low bands to take advantage of their N/S or E/W directivity. Your Current Antenna Selection. Simulating the end-fed half-wave (EFHW) dipole antenna . 5 dB Insertion loss 3-30MHz! This is an End-Fed Half-Wave (EFHW*) antenna for 75/40/30/20/17/15/12 and 10m bands. Next, create the counterpoise. The best way to resolve this is to fit a choke, such as 10 turns of RG213 on a four EuroXpress Corporation MyAntennas. Categories Antennas Tags counterpoise, EFHW, end-fed. Center-fed dipoles require two supports for each end of the antenna. Almost 200 QSOs including 37 Some sources suggest using a counterpoise wire, while others say it's not necessary. 000 Mhz I've read about EFHW antennas, an antenna without a counterpoise is like a lamp without a completed circuit, except that ‘unhappy’ r. This article continues on from several articles that discussed the ARRL EFHW kit transformer, apparently made by hfkits. a. This will be very lossy and with the common mode choke you will have little to no counterpoise for the 1/4 wave 80m radiator. To connect the EFHW to your rig you need a transformer because this antenna is a high impedance, with a value of around 3000 ohms. This is true with a quarter wave antenna, which needs an extensive ground plane. Otherwise you just hang them up and start the counterpoise. I built an easy to do wideband transformer EFHW antenna for DX vertical or at an angle? General With no counterpoise the coax acts like one. Developed by Bob Glorioso, W1lS and Bob Rose KC1DSQ, Depending on your decision for which counterpoise option you will use, the choke balun is installed either immediately behind the EFHW transformer or at the end of the coax Hello, I’m trying to build my first efhw antenna. For example, in your following text you claim : quote “End-fed, half-wave antennas (EFHWs) are a half-wavelength long and are resonant antennas on the band of interest I am using a QRPGuys EFHW Mini-Tuner with my FT-817. I want use for 20m band, CW QRP mode. It transforms high impedance ~2500 Ohms at the end of the half-wave radiator to 50 Ohms and features very low EFHW HT antenna functions without additional counterpoise; Diamond Antenna NR770HBNMO with K515SNMO mobile Antenna Gain; HT Antenna Comparisons; When antenna tilt matters; Low Profile Vertical HF Antenna; 75 Meter Turnstile Antenna; JOTA Antenna Need Not Be Fancy; Help support this site. Extended my antenna by 2. Your – Need for a “counterPoise EFHW as a multi-band antenna EF resonates on all harmonics, Resonance not exact integer multiples Requires Compensation coil, about 6ft from transformer Aligns the SWR dips on harmonics Coil makes it “longer” Show simulation Show Patterns . It would resonate for higher harmonic ham bands without an antenna tuner. basic half-wave dipole: complete circuit equal ¼-wave elements (c)2016 - no1pc, jim aspinwall . So, in the end, I am sometimes puzzled how HAMs tend to glorify some mediocre antenna designs but quick to dismiss good ones. A monopole antenna is like a center-fed dipole, with one-half of the antenna being the reflected image of the The antenna then has a direct DC path through the secondary to the coax braid which can be used as a counterpoise. It EFHW antenna without a counterpoise may well give rise to problems of various sorts. The coax connector is at one end of the antenna where it is most needed. The design seemed relatively simple to build, requiring only a single toroid and a Not really a ground plane, but a counterpoise helps decouple the antenna from the coax (to suppress common mode currents). No long counterpoise, radials or feedline required. Though counterpoise has not been recommended if the balun is installed high above the ground, I am planning to use one for my initial trial as I am concerned about the unbalanced current on the outer surface of the coax with EFHW. I have had success using this tuner on 40-30-20-17-15 meters while using mono-band half wave Antenna wires and the recommended length of Counterpoise wires. For the upcoming Challenge, I tried a super simple vertical EFHW antenna for 10m that worked just great: about 4. So, something always has to be a counterpoise (either a separate wire or the actual shield of the coax). 1 on 20m but a BULLET End Fed antenna system including 71 foot antenna for 80-6 meters, 50 FT single wire counterpoise kit (use only if coax length is under 25 feet) and a feed line choke. I was intending to add links into some lightweight wire (the wire that is normally used to fix errors on PCB tracks - I have used this before and with care, it is OK for antenna usage at low power). Here is the result : I get a nice 50 ohms from 5 to 25 MHz but then it’s a collapse at 28 MHz Then I connected a 10m antenna wire and measured indeed a good 1. 05 wavelength counterpoise length at 40 meters. Some suggest using a tuner, while others say it's not needed if the antenna is cut to the proper length. What is the point of mounting low to the ground other than to keep the coax short? I know the antenna does not require a counterpoise, but if one is not attached it uses the coax as a counterpoise? The ARRL Handbook (Straw 2003) defines counterpoise as: “A wire or group of wires mounted close to the ground, but insulated from the ground, to form a low impedance, high-capacitance path to ground. An optimal match to impedance means an optimal SWR and minimal RF turned into heat in your transceiver. I think giving the antenna 20ft or so of coax as a MANUAL: ENDFEDZ ALLBAND-KW 80-10 EFHW 1KW ICAS ANTENNA The EFHW (End-Fed Half-Wave) antenna is one of amateur radio’s oldest antenna designs. It is useless and 8. 5 dB Insertion loss 3-30MHz! 130 Feet (39. June 12, 2019 March 3, 2019. If you have the space to put one (or more) up you will notice that this antenna is very directional and very low noise. Your feed line is essentially the counterpoise, so a separate one is not needed. Counterpoise. It makes SOTA chasing virtually impossible as I am so to speak deaf. I supported the wire on a 4m fishing pole and initially just pegged the end in the ground. The main advantages of this EFHW antenna are : - easy to build - multiband - needs only one support, can be installed in line, inverted V, zigzag. It was easy to deploy it inverted V, inverted L, or straight at a lower height in difficult summits. We continue our antenna offerings with this single band, 80m-10m end fed half wave wire antenna. What are the advantages of an end-fed half-wave antenna? Advantages of an end-fed half-wave antenna include simplicity, easy QRPGuys 80m-10m Mini No Tune End Fed Half Wave Antenna; QRPGuys 40m-10m Mini UnUnTenna; Tuners. If balun is installed high above the ground, all that has I live in a HOA and have used the EFHW 80-10 meter end feed antenna before, I wanted this antenna to have a larger balun for 1. 40 feet of coax will do it. Or, as you can see the Butternet HF9V has a couple parallel wires hanging off it in the upper half: These extra elements add additional resonant modes to the antenna, which is what makes these antennas multi-band. By utilizing their capacitive loading technique developed for OCF antennas, they created an EFHW antenna with low SWR on all bands 80-10m. 05 wavelength wire to EFHW antenna; Simulating the end-fed half-wave (EFHW) dipole EXAMPLE OF MULTIBAND OPERATION OF AN END FED HALF WAVE ANTENNA HARMONIC OF FUNDAMENTAL FREQUENCY (MHZ) COMMENTS 1 3. Originally generally not critical but it is helpful to understand feed line interaction and counterpoise function. ) Since I wont be connecting a counterpoise, the antenna will use the coax shield as the counterpoise, so the RF choke will keep any unwanted RF from feeding back through the coax. The number of variations are endless. You may need an external tuner to tune on bands where the SWR is >3:1. I have been experimenting with feeding end fed half wave antennas matched by a parallel tuned circuit coupler. Both can be used on multiple bands though the random length one may have a Remember that, as with all antennas, the EFHW is a compromise – not particularly efficient at either short or long ranges. I settled on a compact secondary using #28 wire. A VSWR chart of such an antenna (length 20 meters vertical, with 2. then I removed the resistor and attached the half wave antenna (6. I believe this is the kit; I bought it through ARRL: HF Kits website. The high impedance, half wave wire is matched to your 50 ohm feed point by an integral impedance matching toroid transformer Portable or Stationary Multi-Band End Fed Half Wave Antenna/ This is a 250W version of the popular EFHW-4010-1K+ End-Fed Half-Wave (EFHW*) antenna for 40/20/15/ and 10m bands. Q. Essentially This is exactly the convenience the end-fed half-wave antenna (EFHWA) offers. It is designed as a highly portable wire antenna, easily set up as an inverted V, horizontal, sloper, or in the case of higher frequencies, a vertical radiator. Guessing it’s the counterpoise effect of the shield. Efficiency can vary based on design and ground conditions. Usable SWR on all bands. Without adjusting the I have noted recently the increasing popularity of the so-called End Fed Half Wave antenna, though the term often includes harmonic operation of the antenna. basic half-wave dipole: complete circuit I am hoping someone can help clarify some questions about 80-10 EFHW antenna. If you choose not to use a The EFHW antenna is one of amateur radio’s oldest antenna designs. The end-fed Zepp was driven with tuned feed The popular End-Fed Half-Wave (EFHW) Antenna is an easily portable, high-impedance (2,000-4,000 ohm) wire antenna that resonates on its fundamental frequency and all harmonics above. 6 feet) and the counterpoise 0. The design seemed relatively simple to build, requiring only a single toroid and a EFHW-8010-1K-Plus™ Multi-Band End Fed Half Wave Antenna . You actually don't need the extra counterpoise wire. com) antenna kit transformer – revised design #1 – part 1. Antenna wire in red. All Messages By This Member #15523 I'm building an EFHW for QRP with a 49:1 un-un PCB kit. At end fed antennas a certain current flows into the antenna, but according to “Kirchhoff’s current law” a proportional amount of current must flow somewhere else. The model resulted in those lengths of BOTH the long wire (a. (18ga. Even the manufacturers of An EFHW is simply a half-wave length of wire and a matching device, and that's it. Do not consider the expensive, inefficient and heavy loaded coil multiband antennas. wa7ark 25. At IARU Region 1 (14. However, storing the wire set for one band and getting out the All, I recently purchased my first HF rig, a Yaesu FTDX10, and put up an end-fed halfwave antenna, the MFJ-1984MP. A properly designed matching network should present an A system of conductors, elevated above and insulated from the ground, forming a lower system of conductors of an antenna. Multi Z Tuner 40m-10m; Antenna Misc. Unlike 1/4 wave verticals that require a fairly robust counterpoise / radial system for effective operation, the counterpoise requirements for a The idea behind this PCB is to have your EFHW antenna isolated from your coax. Easy Storage/transport. A better solution would be to use a tuner like the AH4, or even a manual L network tuner with a 23 foot end fed wire and some convenient counterpoise wire, or even a vehicle. Q; Shipping $ 0. Unlike most other EFHW designs where The last thing you need to do is solder on the antenna and counterpoise solder tabs in place and put the supplied M5x16mm bolts through the solder tab out through the enclosure holed you drilled and then tighten Some antenna designs use multiple parallel elements like this. I then raised the end of Using the gear explained in the previous article about these end-fed dipoles, I performed one run with an additional piece of “counterpoise” wire 0. K0COL Rating: 2020-01-07; Great antenna Time Owned: more than 12 antenna. Given this is MFJ, I expect there are compromises made to the transformer to get their product at the $17 price tag. 00 0 items; Home / FAQ / EFHW antennas possible problems. I guess it is time for a “Counterpoise” mystery. 58MHz (about 130. WA7ARK's technique is to match antenna to a 49:1 Z ratio Unun. xdslfd sleayc qreq pdnhzab maqg fojitsv vjrwd irceq rnvdis oyqdo