stretch of twin lead with one of its wires connected to a 68 Ft. If you are after efficiency, coax should never be "tuned" (except in the case of minor mismatch, for instance changing a 3. 73, Mike AF7KR. A few photos were taken while testing the finished antennas and the one pictured above was the 1st one built and prototype for the one seen at the top of the page. The problem with an end fed half wave antenna is that the antenna presents a high impedance, creating a. 8 metres long. However, Guy Olinger,K2AV, has created an alternative – the folded counterpoise (FCP). AIR - RADIORAMA: MLA-M Magnetic Loop Antenna - Multiband 3,5 a 28 MHz QRP. Current wants to flow into a low impedance. The coupler was tuned to resonance on the bench first using a resistive load. The Inverted "L" is a 1/4-wave Marconi, fed against ground or a counterpoise such as radials. 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. Separate the speaker wire into two 50-ft wires. The antenna displays a low feed impedance, which allow you to feed it directly with 50-ohm coax cable. 80 through 10 meters is good, and the KX3 tuner will match it easily. 57 MHz fundamental resonance. 22 milli-metres. For each amount of length trimmed off the short end, trim four times that length off the long end. pdf), Text File (. It is only a quarter-wave on one band. A so-called random wire antenna is an end fed antenna. ***We make this same antenna design in many different lengths. (That dipole may be cut to length on a specific frequency or it may be "however long you can make it", but it's still a dipole, not an end-fed wire. Quadrant antennas produce mostly horizontal polarization at low to intermediate elevation angles and have nearly omnidirectional radiation patterns. counterpoise or an amputated G5RV with a 1/2. 5 meter pole, and the 40 meter half wave looked like the best for 20 and 40 meters. If it isn't end-fed, then it's usually near-center fed and becomes a dipole antenna instead. I have done several Field Strength Readings in the field and in a…. The EFHW transformer can be bypassed with this relay which turns the antenna into a 130' end fed. Separate the speaker wire into two 50-ft wires. I found that I needed to add about a 10 foot long counterpoise to help reduce the RF in the shack on 30 and 17 meters. pdf), Text File (. I have changed the counterpoise wire from 1. If you are after efficiency, coax should never be "tuned" (except in the case of minor mismatch, for instance changing a 3. This method is often called the END-FEED or VOLTAGE-FEED method. The end-fed feature adds convenience, and makes it very portable. •Counterpo. "An Unorthodox Antenna"): an 84' long end fed and a 17' long counterpoise (6. If your tuner has difficulty tuning on 30 or 40 meters using the balanced feedline, tie the feedline togther and feed it like an end-fed wire (in this case, you'll definitely need the counterpoise) Results, and My Impressions. This length would make the antenna resonant at 14. Minimal counterpoise/radial requirements make for a convenient antenna for portable use, and I operate portably about 99%. When originally making these antennas using my antenna analyser I could see that the counterpoise wire also has a critical length for the complete antenna to be resonant on the required band. Rock-Mite transceiver for 40m. Based on the well known W3EDP design, This version incorporates the counterpoise in the 300 ohm ribbon cable. Put 4 horizontal 1/2 wave radials at the base of a 1/2 wave vertical wire and the impedance is ~75 ohms. They also need a counterpoise or earth return to work well and avoid RF getting back into the shack. A quarter-wave – and its odd multiples- presents a low impedance when fed at one end. As per my knowledge any base fed antenna without a counterpoise is in reality only half an antenna. The end fed half wave antenna can be operated with a small counterpoise, and in some instances, no counterpoise is used at all, although this is not necessarily wise. 4m length approx. For the past couple of weeks, I've been playing with end-fed wire antennas. In its simplest form, a counterpoise can be a single wire, one-quarter wavelength long or just slightly longer. I have seen the length of 41 feet mentioned as a good one for multiple band use and I notice that the 10/20/40 PAR end fed antenna is listed as 41 feet long as well. Long-wire antennas require a length greater than a quarter-wavelength (λ/4) or half(λ/2) of the radio waves (most consider a true long wire to be least one wavelength), whereas random wire antennas have no such constraint. SFI of 68 with a sunspot number of zero. 20-30 feet but NOT resonant. 57 MHz fundamental resonance. These antennas can be mounted horizontally, vertically or as a sloper. I have inserted two additional links for coverage on 17m and 30m. An end-fed wire, also called a long wire antenna, is one of the easiest to build and set up. 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. 2019-12-23 I keep being drawn back to this simple antenna. Random wire and long wire. Resonant on specified bands. Again, more is better and will increase efficiency. Then attach a 0. Increasing the resonant frequency of an end fed Marconi antenna can be done by from ENGINEERIN 1 at University of the Philippines Diliman. ; Rugged weather-resistant 50-Ohm matching network. I specifically wanted stranded wire. Once finished trimming, temporarily reconnect the short and long end. The antenna should be connected to your receiver via an antenna tuner with a real wide matching margin. 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. Ver2cal'Wire'Antenna' • Actually'a'ver2cally'orientated' resonate'1/2'wave'dipole'with' the'earth'being'the' return ' half' • Due'to'poor'ground' conduc2vity'a. 20-30 feet but NOT resonant. Youll need the counterpoise otherwise. I understand the basic theory behind how the antenna works. Question I have is about the coax. a monopole antenna one- quarter wavelength long, mounted vertically with the lower end either connected directly to the ground or grounded through the antenna coupling network counterpoise wire structure placed below the antenna and erected above the ground and it should be insulated from the earth ground. Without loss in the system, you'll never see 50-ohms, reactive or not. The VK4YE end fed antenna does need a small counterpoise of 0. This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. The Delta Loop is not only a great transmitting antenna but a low noise receiving antenna. You sound like you have the counterpoise well in hand. You do need an ATU though. 160M Is a Tough Band • Propagation quite variable, signals often not very strong, heavy QRN during the summer –Mostly a nightime band, varies a lot through the night –During the winter, 800 miles or. Repeat the experiments above with the EARCHI end fed matchbox for comparisons. Call us at from central time m f or use messaging sales for us customers only8 Kansas residents pay sales tax. These combinations should provide some interesting results. This length turned out to be 9 metres 87. A counterpoise is simply a long, insulated wire that attaches to the ground connection on your antenna tuner. •Counterpo. Wire type: Copper stranded Color: Grey or Black depending in stock. The counterpoise lays on top of the ground below the antenna. Use the Coil-Shortened Vertical Antenna Calculator to see how. Click on Calculate and the optimum length for that combination will be displayed in feet, inches and fractions of inches, and in meters. A centre feed gives around 70Ω. There has been much written here about counterpoise ground installation, but after reading many post, reference books, etc. These lengths were chosen because they are not resonant on any ham band. Short video on a simple multiband HF antenna (w/tuner) you can put on the air with a few mulitpurpose items in less time than it takes to watch this video. The key to these antennas is to have an elevated counterpoise. This antenna has been made popular by the Emergency Amateur Radio Club of Hawaii (EARCHI). BEVERAGE ANTENNA: This is a long wire horizontal antenna two or more wavelengths long with a 500 Ohm termination connected to a good counterpoise. Note the 20 meter length of wire is connected to the earth side of the capacitor – make that the rotor then the control shaft is also at earth potential so there is no chance of getting a RF burn while tuning. Figures 7 & 8 show that the 100 watt compliance distances for this antenna are longer than for the previous examples for both uncontrolled and public areas respectively. It's an easy…. The figure 8 – blue line (grounded end) is exactly what I am experiencing with my end fed strung at my back yard. To make the best use of an End-Fed antenna, it should be fed with a transformer. 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. The finished length will depend on the wire diameter used. “A half-wave – or its multiples – presents a high impedance when fed at one end. I figure one can't have too many antennas and this one would be a quick build. The end fed feature adds convenience, but does present another issue. This End-fed antenna has a rating of 2kw which is more than enough of a buffer for me. (That dipole may be cut to length on a specific frequency or it may be "however long you can make it", but it's still a dipole, not an end-fed wire. The antenna may be fed at the bottom or at a corner. I have installed 2 good earth rods, and have attached 3 counterpoise wires. So, the counterpoise wire was cut to a length of 16. At a half wave- length on 40 meters, the input impedance will rise to a high value presenting a voltage feed to. B-4: Balun Designs 9 to 1 balun with 1/4 wave counterpoise on ground the antenna current at mid point was 200 ma. Think of the OCFD as a end-fed antenna with a small counterpoise (or a vertical lying on its side ;-) I connect the shield of the coax to the short leg of the off-center-fed dipole. 7) is of actual measured data of an end fed half wavelength antenna with an isolated coupler using an 8:1 turns ratio. 5MHz) therefore also resonant on second, third, and fourth harmonics. See figure 4. While these lengths have been shown to work well on many bands, which is helpful if you're in a hurry to get on the air, read up on the topic and experiment. You do NOT need an additional counterpoise or ground wire with this antenna. They use a parallel resonant circuit and are designed to match an end-fed halfwave (EFHW) antenna. Figure 6 - SWR vs "Counterpoise" Length vs Turns Ratio for an End Fed Half Wave Free Space Antenna. 5MHz) therefore also resonant on second, third and fourth harmonics etc. Delta Fed Dipole Antenna 13 18. Workable: Attach counterpoise stud on unun to a good ground rod at the feed point of the antenna. I tested the 9:1 I created using 450 ohms of resistance connected to the wire end and ground. The dipole has two 1 m long arms - effective height is 1 m. Installation Notes There are several methods of installing the antenna and some are better than. 5 Wave-Length wire on lowest band (130ft on. You sound like you have the counterpoise well in hand. My finished antenna wire length is 2. End-Fed Half-Wave Antenna & Tuner. 45e-6 ‘Coil inductance (4. Resources listed under End-Fed Antenna category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. 5ft counterpoise on 20m. 47 free space wavelength) was determined by modeling the length required to obtain resonance (jX = 0) when the "counterpoise" was the same length. This makes keeps the weight and bulk down while delivering a very strong antenna element. Efficiency: about. The MyAntenna 8010 End Fed is an End-Fed Half-Wave (EFHW*) antenna. Four radials are slit out. Call us at from central time m f or use messaging sales for us customers only8 Kansas residents pay sales tax. 7m) central support and a 12ft (3. ***We make this same antenna design in many different lengths. Unlike many END FED antennas on the market, this one does not require the Antenna Tuner to operate. I really like an EFHW for low power operation. End-Fed Random Wire •Not resonant - covers all bands •9:1 Balun and tuner required 9:1 balun brings the 2000-5000 Ohms down to 250-600 Ohms Within the range of broad-band tuners (LDG, MFJ, etc) Most internal tuners are limited to ~25-150 Ohm tuning range WARNING ! Coax shield becomes the counterpoise Brings common mode RF current back to. Ideal antenna for field portable operations from your local park or backpacking to put a Summit On The Air. Pedestrian dragging counterpoise length With broadly tunable whips (such as MP-1, mobile whips, etc) I've found impirically that a pedestrian dragging counterpoise wire can be about 10% to 25% shorter than the standard quarterwave formula predicts, and the whip will usually tune to a fairly good 50ohm match. 6 Meter 5/8 Wave Vertical Antenna The G3JVL 6 Meter ground plane vertical is a compact antenna that is ideal for portable operations. 5 Meter wire with a antennae tuner you can work 10 to 80 meters. The problem with an end fed half wave antenna is that the antenna presents a high impedance, creating a. Separate the speaker wire into two 50-ft wires. Setup the end fed antenna on the 3rd floor condo balcony this afternoon. Start with a longer length and trim for a low VSWR. long, the other 90 ft. End-Fed Half-Wave Antennas. Minimal counterpoise/radial requirements make for a convenient antenna for portable use, and I operate portably about 99%. Grey wire was used as this is virtually invisible from about 10m way. 0 ‘Height of ends above ground SY ApexHeight=4. As per my knowledge any base fed antenna without a counterpoise is in reality only half an antenna. The formost and most important item is to have the matching device at the antenna's feedpoint and a good ground / ground system at the feedpoint as well. Resonant on specified bands, no tuner needed!. Connect the VNA now at this center location to determine the required reactances for resonance at 3. Below is one example of how to build an 80 metre band long wire antenna for a house with a smaller garden. The dipole referred to here to is a 1/2 wave dipole. These antennas can be mounted horizontally, vertically or as a sloper. The antenna current at midpoint was 210 ma. The recommended antenna wire length is 30 feet. Wideband Dipole for Receiving 16 24. They are sup-ported by PVC pipe with T connectors at the top fashioned around his fenceline. It is a resonant Half wave on 80m (3. The End-Fed Inverted “V” is a good compromise between performance and ease of installation since it requires only one center support, has a reasonably small foot-print, and provides good sky wave propagation. To capture the 80m‐Band the counterpoise cable length has to be at least 80m x 0. Portable End-Fed 40-6 Meters Poly-Stealth Dipole Antenna 4. 5′, 29′, or 17′ and optionally a 1/4 λ wire for a counterpoise, 35′ or 16′ length counterpoise works well for all bands. This antenna has been made popular by the Emergency Amateur Radio Club of Hawaii (EARCHI). 5' for 20m). The coil’s Inductance is 118uH and requires 61 turns of close wound 0. The antenna cannot be an actual 1/4 wave length on any ham band. 66) end support. The first 6ft (1. It works on 80/40/30/20/17/15/12 and 10 meter bands. I chose to use Wireman 532. In theory the antenna end impedance should drop to about 1800 ohms. long wire for a total physical length of 85 Ft. The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. Resonant on specified bands, no tuner needed!. From the second wire, cut a length that is about 16′ 9″ or so. pdf), Text File (. The default length is 53 feet and the antenna can be extended to 124. According to the AA5TB graph, at this counterpoise length the reactance. 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. 0 VSWR to 1:1 - the idea being that at 3:1 or less with good rg-8 or better coax on the lower frequencies, the. 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. 35 MHz @ 31 Meter Band. End-fed antennas with one end up in a tree should be easy to manage, but aren't easily matched to a transmitter. I purchased my 'MFJ-1984MP end fed 1/2 Wave 300W 40M-10M Wire Antenna' from a local ham radio outlet store. May 12, 2016 - END-FED ANTENNAThe ULTIMAX DXTREME end-fed antenna covers from 1. I have installed an inverted L, end fed antenna, with a single wire feed length of 31'-6" connected to an MFJ-941 Versa Tuner II. Question I have is about the coax. This configuration is terribly inefficient because the antenna is a fraction of a wavelength it should be. Add three more 20 ft counterpoise for a total of 4. The key to these antennas is to have an elevated counterpoise. ***We make this same antenna design in many different lengths. Think of the OCFD as a end-fed antenna with a small counterpoise (or a vertical lying on its side ;-) I connect the shield of the coax to the short leg of the off-center-fed dipole. 62 m) of Dacron rope. To optimize the antenna for a frequency RANGE, do the calculations twice, once for the low end of the range and once for the high end; then average the two and plan to adjust the VSWR on both ends of the range as needed. ; Rugged weather-resistant 50-Ohm matching network. Others say that you can use a 6. End-fed antennas with one end up in a tree should be easy to manage, but aren't easily matched to a transmitter. ***100% ALL Stainless Steel Hardware. 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. Look at the following backyard antenna setup. The #26 black polyethylene jacketed Polystealth™ wire is light weight yet strong. Specially made for Small garden and stealth user comes complete with winder to store away with ease while on the move. Resources listed under End-Fed Antenna category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. END FED, HORIZONTAL WIRE ANTENNA : Note: This listing is for one MFJ-1982MP. 647 MHz and 10. In this configuration PAR End-fed half-wave antenna. If possible run the counterpoise above groundaway from or perpendicular to the antenna wire and do not ground the counterpoise at the unun. 20-30 feet but NOT resonant. To make the best use of an End-Fed antenna, it should be fed with a transformer. long overall (the size of a single band 40 meter dipole), covering 40, 20, 10 and the low end of 6 meters. Experience has shown that most external tuners and many internal tuners will tune 80–6 meters with an antenna length of 22’ to 30’. Antenna gain relative to a dipole antenna can be expressed in decibels as dBd. One of the simplest antennas for the lower HF bands is the humble inverted-L. I have installed an inverted L, end fed antenna, with a single wire feed length of 31'-6" connected to an MFJ-941 Versa Tuner II. With the EFHW the earth (or a counterpoise) is still important, but not quite as crucial. Further tweeking of the link coupling would be required to achieve a low SWR. The UV resistant ABS plastic housing encloses an efficient matching network allowing the antenna to be fed with common 50 ohm coaxial cable on the SO-239 connection. limited space antenna only approx 67 ft. I found that I needed to add about a 10 foot long counterpoise to help reduce the RF in the shack on 30 and 17 meters. The formost and most important item is to have the matching device at the antenna's feedpoint and a good ground / ground system at the feedpoint as well. I understand the basic theory behind how the antenna works. In this configuration, the coax shield will act as your counterpoise. I have the current Rybakov antenna setup as a baseline. Unlike many END FED antennas on the market, this one does not require the Antenna Tuner to operate. Once I find the sweet spot on the tuner, I nibble a quarter inch at a time off the antenna wire and slowly walk the wire resonant frequency up to where I want it to be. 20 Meter Loop • My next attempt was a 2. Random wire and long wire. The coupler was tuned to resonance on the bench first using a resistive load. Resonant on specified bands, no tuner needed!. It's possible to work from a counterpoise alone without an earth connection at all. An included innovative drip blocking accessory called a Drip Dam prevents water droplets from running down the radiator to the operating position. The lower end of the antenna may also be grounded as an alternative to reduce static noise. The best way to resolve this is to fit a choke, such as 10 turns of RG213 on a four. According to the AA5TB graph, at this counterpoise length the reactance. A standard recommendation (see QST, March 1936, p. Many compromise antennas are the 6 to 12 foot variety. This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. No long counterpoise, radials or feedline required. To install one, you must use an antenna tuning unit. The key to end fed antenna success is the matching network interface between the long wire antenna and the coax feed line and feed line choke at the transceiver. several) or a counterpoise wire. Any counterpoise should be at least 1 foot above ground running away from, or perpendicular to the antenna wire. Pedestrian dragging counterpoise length With broadly tunable whips (such as MP-1, mobile whips, etc) I've found impirically that a pedestrian dragging counterpoise wire can be about 10% to 25% shorter than the standard quarterwave formula predicts, and the whip will usually tune to a fairly good 50ohm match. Most ground is very lossy and therefore a counterpoise or counterpoises ought to make a significant difference regardless of the length of feeder you use. a monopole antenna one- quarter wavelength long, mounted vertically with the lower end either connected directly to the ground or grounded through the antenna coupling network counterpoise wire structure placed below the antenna and erected above the ground and it should be insulated from the earth ground. A standard recommendation (see QST, March 1936, p. 647 MHz and 10. We build CB antennas, UHF antennas, VHF antennas and more, using modern tooling. Construction Notes. I understand the basic theory behind how the antenna works. This cable belongs to the unsymmetrical antenna! The length is calculated by "Lambda x 0. (For 20 meters) The length of 468/14. Separation is the term used for the distance between the driven-element and the counterpoise. It's nothing more than a 9:1 unun with a 29 ft #26 wire radiator and a 17 ft #24 speaker wire counterpoise. The 9:1 UnUn for this antenna uses a FT240-K ferrite toroid wound. This would require a 6:1 turns ratio. No ground plane or counterpoise is needed. 20 - 10 Meter Multi-Band End-Fed Long Wire Antenna Here's a great end-fed long wire 20 - 10 Meter multi-band antenna, a smaller version of our popular 80 meter version. The UV resistant ABS plastic housing encloses an efficient matching network allowing the antenna to be fed with common 50 ohm coaxial cable on the SO-239 connection. End-Fed Half-Wave Antennas. You cannot simply connect a generator of RF energy to the end of a wire and expect to have an optimal radiating system. Due High Impedance feed point, the antenna is less. All hardware is stainless steel. The 9:1 UnUn for this antenna uses a FT240-K ferrite toroid wound. End Fed Half Wave Antennas VS Random Length End Fed Antennas - Duration: 18:04. The finished length will depend on the wire diameter used. In my experience, I normally use the half length of the antenna wire. Not ideal for length of the copper strips, but at least one would be about 7 metres. A counterpoise is simply a long, insulated wire that attaches to the ground connection on your antenna tuner. 2) Raise the antenna to its desired position and determine the frequency of lowest SWR, f 2. Two ceramic or plastic end. Some books say that you don’t use the counterpoise at all on 10m. I found that I needed to add about a 10 foot long counterpoise to help reduce the RF in the shack on 30 and 17 meters. It's connected to my rig with a 25 ft piece of RG-58 coax. Other fractions of the wavelength can be used, but the impedance matching becomes more complex. Ver2cal'Wire'Antenna' • Actually'a'ver2cally'orientated' resonate'1/2'wave'dipole'with' the'earth'being'the' return ' half' • Due'to'poor'ground' conduc2vity'a. End fed 5 band wire antenna for 80m, 40m, 20m,15m, 10m, short version with wire length 23m. You can also use the unun with no counterpoise or ground if your feedline is at least 25+ feet long. 5MHz) therefore also resonant on second, third, and fourth harmonics. End fed 3 band wire antenna for 40m, 20m and 10m. 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. It is a resonant Half wave low on 80m (3. Note that any of these lengths are going to be long on 6 meters. In theory the antenna end impedance should drop to about 1800 ohms. A quarter-wave – and its odd multiples- presents a low impedance when fed at one end. End-Fed Half-Wave Antennas. This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. Review Ultimax DXtreme 124 Ft End Fed Antenna 6-160 Meters - Duration: 4:20. My take on a QRP HF EFHW inverted V antenna designed for use on five amateur radio bands…. 225 15 44 deg 50 ft. Each model resonates at the low end of the respective 160, 80 or 40m. As in any vertical type antenna, a ground radial system or counterpoise is essential for maximum results. Thus, matching can be achieved without the need for a separate matching network. 3) Assuming that f 2 is too low (the antenna is too long), calculate the desired length 2 = 1 × f 2 / f 1. Marconi antennas or end-fed antenna systems located far from earth require counterpoises. Tilted Folded Dipole Antenna 16 25. 5, 41, 58, 71 and 84 feet. Linearly Loaded Tee Antenna 17 27. Umbrella – Very large wire transmitting antennas used on VLF bands. It's connected to my rig with a 25 ft piece of RG-58 coax. If it isn't end-fed, then it's usually near-center fed and becomes a dipole antenna instead. It is a resonant Half wave on 80m (3. The simulations were performed for ideal (lossless) antenna elements with a diameter of 1. 47 free space wavelength) was determined by modeling the length required to obtain resonance (jX = 0) when the "counterpoise" was the same length. The Buddistick, SuperAntenna MP1, Pac-12, and a Chameleon (it has various variants) all offer a short antenna with multi band capability. The key word is DIPOLE, meaning it has 2 poles. 05 wavelength counterpoise to the 'cold' end of the secondary. 2 m radial, giving a vertical cut at l/2. 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. One such antenna is the W3EDP end fed. Whether you're looking for a portable antenna or trying to put up a covert antenna that really works and won't bother the neighborhood, this is a great solution. It is a resonant Half wave on 80m (3. By adjusting the counterpoise length, you will be able to compensate for varying conditions due to surrounding objects, grounds, etc. NEW 200W PEP VERSION!!! Easy and fast installation. 132' Length. Mark pa1ssb heeft een 80 meter qro end fed gebouwd met een tegencappaciteit. The coax feedline can also serve as a counterpoise but I read varying reports of improved results with a wire counterpoise so I choose to experiment with and without one. End fed 7 band wire antenna for 80m, 40, (20m, 17m) 15m, 12m, 10m. 7) is of actual measured data of an end fed half wavelength antenna with an isolated coupler using a 8:1 turns ratio. PackTennas are light weight, compact, portable HF antenna systems ideal for operating on the trail, at the campsite, on Field Day, SOTA activation, air travel, or HOA restricted locations. Since a vertical (Inverted L) is really a end-fed antenna it requires some form of path for the return current which typically is either an elevated or buried radial system. Antenna Height and Communications Effectiveness By R. The best way to resolve this is to fit a choke, such as 10 turns of RG213 on a four. The Inverted "L" is a 1/4-wave Marconi, fed against ground or a counterpoise such as radials. Often random wire antennas are also (inaccurately) referred to as long-wire antenna. The overall length of the antenna is 76' (22' for each doublet leg plus 54' of feedline) so this antenna should be easy to tune on 10, 15, 20, and 40m. 3:1 or better on all bands. So, for a 1/4 wavelength antenna element divide your result by 4. 36 60 175 deg ft. All in all, this is one great antenna and it even works very well on 2 meters! The SWR on 2 mtrs. I tested all three configurations and found that #3, no ground or counterpoise, gave far and away the best results for me - SWR 1. The unit is placed between the receiver or transmitter and the wire. (The high impedance of the end fed half wave means not much of a counterpoise is required. You sound like you have the counterpoise well in hand. Re: End-fed wire question. 43 m) and 45 ft (13. It is a resonant Half wave low on 80m (3. In my experience, I normally use the half length of the antenna wire. Others say that you can use a 6. Likewise the counterpoise is a 30 foot length of ribbon cable with 8 conductors. 21 ‘Length of whole antenna SY L=4. The lower end of the antenna may also be grounded as an alternative to reduce static noise. 5MHz) therefore also resonant on second, third, and fourth harmonics. Above are 135/140 foot wires that can be used for radiators with a pigtail as an End Fed Halfwave (EFHW) antenna if you insist. I use a 29 foot wire with my PackTenna 9:1 balun for 40m-10m and then add a 28 foot length for better coverage on 80m when needed. At the end of the parallel feed (450 Ω) any length of coax can be used (balun version required). There has been much written here about counterpoise ground installation, but after reading many post, reference books, etc. Similarly, the half-size version may be used thus on 80m and 160m bands. about 15-20 meter long if I use a 41 meter long antenna wire. sideband!) This antenna is my mainstay and can always be counted on to perform well for "short skip" when my 160 end fed or G5RV do not. The simplest method of feeding energy to the half-wave antenna is to connect one end through a capacitor to the final output stage of the transmitter. Above are 135/140 foot wires that can be used for radiators with a pigtail as an End Fed Halfwave (EFHW) antenna if you insist. 32, "An Unorthodox Antenna") is an 84' long end fed and a 17' long counterpoise (6. 647 MHz and 10. Now, and I stand to be corrected on this; if you are using a balun your coax should not be be part of the antenna system and an end fed antenna works against ground. Here is a side view of the equiptment. The end fed antenna is essentially half a dipole, it uses a good earth connection to complete the arangment. 5, 41, 58, 71 and 84 feet. After some research on the Internet, I decided to build another antenna. Shorter length counterpoise wires can be used of operation is confined to 40m or higher. 983 likes · 2 talking about this. ( not recommended for any of the HW-end fed models ) Description: Length of lead wire to network: 6' ft. QRP Multi-band HF EFHW antenna for SOTA Post updated 29 September 2017. In practice it's best to make the antenna a little longer than the calculated value and then trim it to get the best SWR value. 5MHz) therefore also resonant on second, third, and fourth harmonics. Length of the vertical element:--You can shorten your vertical antenna by using a loading coil. Increasing the resonant frequency of an end fed Marconi antenna can be done by from ENGINEERIN 1 at University of the Philippines Diliman. Note that any of these lengths are going to be long on 6 meters. 4-Band OCF is 68 feet long, 7-Band is 135 feet long, and 8-band is 270 feet long. Wideband Dipole Antenna 15 23. The counterpoise lays on top of the ground below the antenna. Multiband Tuned Doublet Antenna 14 21. 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. Below is one example of how to build an 80 metre band long wire antenna for a house with a smaller garden. "An Unorthodox Antenna"): an 84' long end fed and a 17' long counterpoise (6. You cannot simply connect a generator of RF energy to the end of a wire and expect to have an optimal radiating system. The coupler was tuned to resonance on the bench first using a resistive load. Length of counterpoise should be a minimum of 30-40 feet but not the same length of the antenna wire. The length of the counterpoise depends on the antenna wire or. 9 MHz continuous and is rated at 2 KW (SSB) , 1. 45e-6 ‘Coil inductance (4. 36 60 175 deg ft. Additionally, to the permanent earth connection, a number of counterpoise radials can be added to enhance performance. 5' for 20m). The antenna may be fed at the bottom or at a corner. Long-wire antennas require a length greater than a quarter-wavelength (λ/4) or half(λ/2) of the radio waves (most consider a true long wire to be least one wavelength), whereas random wire antennas have no such constraint. leg will be removed, making an antenna which now. A ‘Windom’ type off centre fed dipole (fed 38% along its length) provides around a 200Ω feed. tidbit of info on the sleeve dipole. The magic lengths to use with the End Fed longwire is 29, 35. To meet these criteria, the antenna wire will need to be between 175 and 215 feet in length, and the horizontal section must have a height of 50 to 65 feet at each end. The magic lengths to use with the End Fed longwire is 29, 35. If I can’t use that, I’ll fall back to either a monoband vertical with elevated ground-plane, or to a 42ft end-fed wire (with counterpoise on the ground of about the same length) fed almost directly into the rig. Portable End-Fed 40-6 Meters Poly-Stealth Dipole Antenna 4. My finished antenna wire length is 2. Being an End Fed Zepp antenna, no counterpoise nor grounding is necessary. I can wind it up in figure 8 fashion between my thumb and little finger on one hand. This antenna has been made popular by the Emergency Amateur Radio Club of Hawaii (EARCHI). 5, 41, 58, 71 and 84 feet. The 80 meter length of wire will be your radiator and the 20 meter length will be your counterpoise. 15 40 131 10. When fed at the bottom of one of the wires against a small ground counterpoise, the feed point is a high-impedance, voltage-feed. 983 likes · 2 talking about this. Above applies when in free space. Since a vertical (Inverted L) is really a end-fed antenna it requires some form of path for the return current which typically is either an elevated or buried radial system. Review Ultimax DXtreme 124 Ft End Fed Antenna 6-160 Meters - Duration: 4:20. Look at the following backyard antenna setup. A difference in the current flow between the two will cause Common-Mode (CM) differential current to flow, usually along the outside of the feedline coax. Length of counterpoise should be approx. Antenna") is an 84' long end fed and a 17' long counterpoise (6. Many compromise antennas are the 6 to 12 foot variety. Radiobanter. 10m counterpoise produced excessive impedance at the end fed transformer secondary, which the transformer was not designed to match. ; No long counterpoise, radials or feedline required. I may give this length a try. 5ft counterpoise on 20m. The W3EDP end-fed antenna is a cheap way of getting multi-band operation, especially if you are a newcomer and restricted to 10W. 8 metres long. The EMCOMM III Portable antenna End-Fed Inverted “V” configuration, see figure (1), is a medium range HF antenna. MFJ-1984LP EndFed 1/2 Wave 30W 40M-10M Wire Antenna 66 feet. To install one, you must use an antenna tuning unit. 80 - 10 Meter HF Stealth-Portable I am looking for way to create a good grounding system for my HFedz end fed antenna. (4) When installing, ensure that the drain hole in the body of the balancing network is facing down. This is the feed impedance and SWR of an end fed 80 meter half wave with an ideal 49:1 transformer and good stable counterpoise or ground. > Gary and all, > > That length is close to the W3EDP antenna length - as I recall, it is 86 feet for the radiator and 17 feet for the counterpoise wire. The Par End-Fedz are a full length half wave dipoles, but with an important difference. on the 20 m band this antenna 6m high must be completed with a 5. 0 ‘Length from start to coil SY Lcoil=0. The dipole has two 1 m long arms - effective height is 1 m. EBAY ITEM NUMBER 202997373525 Tiny and light weight but ready and capable to put in work!. Pete called it the “No Counterpoise” antenna, and he’s done considerable EZ-NEC work on it. A 1/2 wave folded dipole will be ~300 ohms. The position of the feed point determines the antenna impedance. The W3EDP is a simple antenna: it comprises a 17 Ft. ; Rugged weather-resistant 50-Ohm matching network. More counterpoise wires are always better, because the more you use the less critical length is and the lower loss is. 57 MHz fundamental resonance. 160 meters and 80 meters requires large sized antennas to attain any efficiency. have an unbalanced antenna connection. The Par End-Fedz are a full length half wave dipoles, but with an important difference. Vice versa if it is n-Halfwaves long…. The lower end of the antenna may also be grounded as an alternative to reduce static noise. An Off-Center-Fed (OCF) dipole with total span of 84+17=101 ft, with the feed point at 1/6th of the total span (101 / 6 ≈ 17 ft = 17%) from one end ( = 83 / 17 OCF). Resources listed under End-Fed Antenna category belongs to Antennas main collection, and get reviewed and rated by amateur radio operators. Each pole is 1/4 wavelength. However, we can reduce the space needed to a quarter wavelength if we decide to use an end fed antenna. 6 35 –j332 1/4 wl 90 degrees 17. To meet these criteria, the antenna wire will need to be between 175 and 215 feet in length, and the horizontal section must have a height of 50 to 65 feet at each end. 05 wavelengths at the lowest operating frequency. The Inverted "L" is a 1/4-wave Marconi, fed against ground or a counterpoise such as radials. It's nothing more than a 9:1 unun with a 29 ft #26 wire radiator and a 17 ft #24 speaker wire counterpoise. Counterpoise can be in the same plane as the antenna (i. Because the ½-λ end-fed whip is a complete antenna, it’s the best choice for remote-mounting when a ground-plane isn’t available. Please see our other "QSO-KING" antennas on E-Bay to find the perfect length for you. If I can’t use that, I’ll fall back to either a monoband vertical with elevated ground-plane, or to a 42ft end-fed wire (with counterpoise on the ground of about the same length) fed almost directly into the rig. Additionally he’s phased two 20M versions in a vertical configuration. Further tweeking of the link coupling would be required to achieve a low SWR. The end fed offers many alternative options. 2) Raise the antenna to its desired position and determine the frequency of lowest SWR, f 2. In my experience, I normally use the half length of the antenna wire. 15 dB) over an isotropic source. This antenna requires at least 25′ of coax feed line with no chokes. 43 m) and 45 ft (13. A ‘Windom’ type off centre fed dipole (fed 38% along its length) provides around a 200Ω feed. 55 mc CW band. 5' for 20m). CB Marine Antennas 2; Centre Loaded 2; Discone 10; Dual Band (2m/70cm) 42; Dual Band (6m/4m) 3; End fed wires 15; End Fed, 40-10M, 30W Low Power Wire Antenna MFJ-2982 Feather Lite HF Vertical Wire Antennas are 31 ft. This is an End-Fed Half-Wave (EFHW*) antenna for 80/40/30/20/17/15/12 and 10m bands. In an instructable, the formula for calculating antenna length was given as "length in meters =300 / frequency in MHz". The antenna properties of the screwdriver and a magnetic loop function entirely different!!!!! BTW: The ONLY way the inductively greatly shortened radiators work is to introduce loss. 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. Length of counterpoise should be approx. The ideal radiator length is one that avoid harmonic multiples (1/4 or 1/2) of the operating frequencies. 5ft counterpoise on 20m. The Par End-Fedz are a full length half wave dipoles, but with an important difference. Counterpoise (ground system) is similar to these topics: Beverage antenna, Ground dipole, Random wire antenna and more. An included innovative drip blocking accessory called a Drip Dam prevents water droplets from running down the radiator to the operating position. For the on-going 2007 ARNSW Homebrew Group Challenge work I needed a simple 80 metre antenna. Without loss in the system, you'll never see 50-ohms, reactive or not. It works on 80/40/30/20/17/15/12 and 10 meter bands. If it's going to be about half a wavelength (~66 feet), it'll be an end fed half wave (EFHW) antenna. NEW 200W PEP VERSION!!! Easy and fast installation. I have inserted two additional links for coverage on 17m and 30m. At a half wave- length on 40 meters, the input impedance will rise to a high value presenting a voltage feed to. Two ceramic or plastic end. Above are 135/140 foot wires that can be used for radiators with a pigtail as an End Fed Halfwave (EFHW) antenna if you insist. I purchased my 'MFJ-1984MP end fed 1/2 Wave 300W 40M-10M Wire Antenna' from a local ham radio outlet store. The key word is DIPOLE, meaning it has 2 poles. Each pole is 1/4 wavelength. With the end-fed half wave version of the “Mini” and about 31′ of wire, we can get a 1. Not ideal for length of the copper strips, but at least one would be about 7 metres. Shorter length counterpoise wires can be used of operation is confined to 40m or higher. I have changed the counterpoise wire from 1. Triangle Antenna; Triband end fed half wave antenna for portable use. Others say that you can use a 6. Once finished trimming, temporarily reconnect the short and long end. The Zepp is composed of a 25 foot matching section and a 50 foot radiator section. 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. Its length is not critical, and it does not have to run directly under the antenna wire. The EFHW transformer can be bypassed with this relay which turns the antenna into a 130' end fed. The end fed wire antenna produces quite complex radiation multi-lobe patterns unlike the simple “figure of eight” radiation pattern produced by a dipole. Start with a longer length and trim for a low VSWR. stretch of twin lead with one of its wires connected to a 68 Ft. The 9:1 UnUn for this antenna uses a FT240-K ferrite toroid wound. Length of counterpoise should be approx. A multi-band end fed wire antenna presents a potential problem in that a ¼ wave length antenna cut for say the 80 metre band will present a feed impedance of about 70 ohms however when the same antenna is used on the 40 metre band the feed point impendence will be several thousand ohms and therefore difficult to achieve a match even with a. 15 dB) 10log (1. radial RF ground field cancellation that other solutions do not offer. See figure 4. Antenna tuner is needed on 20 and 17m and to extent the bandwidth on 10m. counterpoise or an amputated G5RV with a 1/2. He also shows us. Two ceramic or plastic end. No ground plane or counterpoise is needed. The figure 8 – blue line (grounded end) is exactly what I am experiencing with my end fed strung at my back yard. I have a few questions about a counterpoise in general. 35 MHz @ 31 Meter Band. The length of the counterpoise is not critical. It's an easy…. The end fed half wave antenna can be operated with a small counterpoise, and in some instances, no counterpoise is used at all, although this is not necessarily wise. 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. Length of counterpoise should be a minimum of 30-40 feet but not the same length of the antenna wire. No ground or counterpoise, just let the coax shield act as your counterpoise. In other words these radials fully participate. Additionally, to the permanent earth connection, a number of counterpoise radials can be added to enhance performance. He also shows us. Length of counterpoise should be a minimum of 30-40 feet but not the same length of the antenna wire. Another old-time antenna is an off-center-fed dipole, called a Windom way back when. 130 metres, which includes an extra 15 mm on each side for feed point strain relief. In my experience, I normally use the half length of the antenna wire. The key word is DIPOLE, meaning it has 2 poles. This is the feed impedance and SWR of an end fed 80 meter half wave with an ideal 49:1 transformer and good stable counterpoise or ground. ; No long counterpoise, radials or feedline required. 32, "An Unorthodox Antenna") is an 84' long end fed and a 17' long counterpoise (6. This antenna normally has about a 3 DB gain over a 1/2 wave center fed dipole. By adjusting the counterpoise length, you will be able to compensate for varying conditions due to surrounding objects, grounds, etc. The default length is 53 feet and the antenna can be extended to 124. From the second wire, cut a length that is about 16′ 9″ or so. Something like the EARCHI end fed with the 9:1 balun. The antenna current at midpoint was 210 ma. A few photos were taken while testing the finished antennas and the one pictured above was the 1st one built and prototype for the one seen at the top of the page. about 15-20 meter long if I use a 41 meter long antenna wire. Think of the OCFD as a end-fed antenna with a small counterpoise (or a vertical lying on its side ;-) I connect the shield of the coax to the short leg of the off-center-fed dipole. END FED, HORIZONTAL WIRE ANTENNA : Note: This listing is for one MFJ-1982MP. Start with a longer length and trim for a low VSWR. It is for these reasons that 40 metres is a good length for an end-fed wire antenna for the HF bands. 5, 41, 58, 71 and 84 feet. I understand the basic theory behind how the antenna works. The roof being about 3 metres x 6 meters. To optimize the antenna for a frequency RANGE, do the calculations twice, once for the low end of the range and once for the high end; then average the two and plan to adjust the VSWR on both ends of the range as needed. The antenna may be fed at the bottom or at a corner. To capture the 80m‐Band the counterpoise cable length has to be at least 80m x 0. It is only a quarter-wave on one band. As for the wires I use two conductors from 28 gauge computer flat cable for the radiator. The #26 black polyethylene jacketed Polystealth™ wire is light weight yet strong. We sometimes cannot freely choose our ground or counterpoise systems. stretch of twin lead with one of its wires connected to a 68 Ft. Figure 6 - SWR vs "Counterpoise" Length vs Turns Ratio for an End Fed Half Wave Free Space Antenna. Length of counterpoise should be a minimum of 30-40 feet but not the same length of the antenna wire. 5ft counterpoise on 20m. 10m counterpoise produced excessive impedance at the end fed transformer secondary, which the transformer was not designed to match. 15 dB) 10log (1. 8m) of 100ft (30. txt) or read online for free. Sidebar: This antenna is very different from antennas fed with coax which require a tuner in the shack. We build CB antennas, UHF antennas, VHF antennas and more, using modern tooling. Triangle Antenna; Triband end fed half wave antenna for portable use. He used a T200-6 toroid (400 watts) with 35-36 turns coil. 3) Assuming that f 2 is too low (the antenna is too long), calculate the desired length 2 = 1 × f 2 / f 1. The end fed feature adds convenience, but does present another issue. 45e-6 ‘Coil inductance (4. The RADIO WORKS' SuperLoop 80™ is a high performance, full size, full-wave, 80 meter loop antenna. The full-size G5RV will also function on the 160m band if the station end of the feeder (either balanced or coaxial-type) is strapped and fed by a suitable antenna tuner using a good earth connection or a counterpoise wire. All hardware is stainless steel. 4m length approx. As in any vertical type antenna, a ground radial system or counterpoise is essential for maximum results. Due to local ground conditions, antenna height and feed line length, SWR may vary and an antenna tuner may be required or some bands to bring SWR at end of feed line to acceptable levels. For example, if you are getting RF problems on 20m (14MHz), a PVC-coated wire or counterpoise cut to a length of 5m may resolve many of the EMC issues. Any counterpoise should be at least 1 foot above ground running away from, or perpendicular to the antenna wire. To optimize the antenna for a frequency RANGE, do the calculations twice, once for the low end of the range and once for the high end; then average the two and plan to adjust the VSWR on both ends of the range. It’s made up of a certain length of wire that is connected to a transmitter or receiver. The lightweight loading coil was wound on a 52mm diam Black Pepper Corn Spice Tub. 5' for 20m). ) I modeled several types of antennas using the 11. 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. For example, if you are getting RF problems on 20m (14MHz), a PVC-coated wire or counterpoise cut to a length of 5m may resolve many of the EMC issues. Antenna gain relative to a dipole antenna can be expressed in decibels as dBd. A centre feed gives around 70Ω. "An Unorthodox Antenna"): an 84' long end fed and a 17' long counterpoise (6. long overall (the size of a single band 40 meter dipole), covering 40, 20, 10 and the low end of 6 meters. Traditional buried or elevated radials, full size, dense, uniform length and spacing, remain the best possible option as they have a high degree of vertical vs. 20-30 feet but NOT resonant. When fed at a corner, the feed point is a low-impedance, current-feed. 35 MHz @ 31 Meter Band.