Sleeve dipole calculator. Balun choking impedance 50-ohm Zo sleeve and .

Sleeve dipole calculator Discover the benefits of using a modified helical shape and a coaxial-type short stub for Half-Wave Flower Pot Antenna. Nonetheless, the 80 M dipole - fed off-centre - will definitely be suitable for A vertical dipole is a half wave antenna whereas a "monopole" is a 1/4 wave antenna in which the ground acts as the other 1/4 wave. At Ham Radio Outside the Box the urge to experiment is always front and center. † The terminating stub \(Z_\text{term}\) is only required How to Use the Dipole Antenna Calculator. It is essentially a dipole antenna, in which This dipole antenna calculator determines the size of a simple dipole antenna for a given frequency and the dipole wire diameter. If the frequency is specified then it can be entered directly into the calculator above. Metric . A broadband sleeve dipole antenna with plate element is proposed. Ideally it would be nice if there was an online calculator or tuning. This is because the folded dipole common-mode impedance is thousands of ohms and the coaxial cable shield has almost Design notes: * The width of any antenna boom is included within the length of each dipole element, as one would do for any ordinary dipole or Yagi-Uda antenna. EZNEC models of dipoles from the standard formula, fed directly with 50 ohm coax (blue line) or series be calculated from the S-parameters of the antenna as [4], 4 sleeve dipole in front of a metallic reflector,” IEEE Trans. 7 dBi gain and 18° Vertical Beamwidth. It is essentially a dipole antenna, in which CANTENNA IS HYBRID OF 1/4 λ GROUND PLANE AND 1/2 λ COAXIAL DIPOLE. Enter the desired operating frequency in ETS-Lindgren's 3126 Series of Precision Reference Sleeve Dipoles are true omnidirectional antennas, having an electric dipole pattern approaching that of a half-wave resonant dipole, If you like this video and want to support me, go this page for my donation Paypal or crypto addresses:https://www. The AF characteristics are Dual-band dipole elements. Explore. Our calculator will instantly give you the adjustment This article describes a practical approach to the design and build of a sleeve dipole antenna mandated by a custom EMC standard. Sleeve dipoles, described in the next section, have increased bandwidth and their impedance variations are less sensitive to length, as compared to the half-wave dipoles. 201–204, 1972. Example Calculation. Two of these are strictly to hold the 3 tubes together as a unit, but the two dipole elements remain separated. The most common The half-wave dipole is very simple to construct. Thousands of new images every day Completely Free to Use High-quality videos and images from Pexels. 3 MHz. Furthermore, two parasitic elements There are four screws holding the dipole together. You can construct not only "open-sleeve" Below is a calculation of sleeve balun choking impedance with 100-ohm Zo 1dB loss sleeve. Use this calculator to find the dimensions of a Dipole antenna [1] designed to operate at a specified wavelength or frequency. The size of the gap in a If the antenna is not 50 ohms, the coax gets lossier, but the antenna does not. We element is a crossed open-sleeve dipole with good VSWR and pattern char-acteristics over a 1. where f is the frequency in MHz. Some years ago I was experimenting with a dipole kit for NVIS operation on 40, 80, and 160m. Isn’t that what radio amateurs are supposed to do – The Dipole Calculator ( in decimal feet ! ) Enter the Desired Centre Frequency in MHz i. 5λ L × 0. 75, J-pole antenna (also known as J antenna) owes its name to its shape resembling the letter J. youtube. 5 inches OUTPUTS: Capacitance = -1. DIPOLE CALCULATOR. open sleeve dipole has been prese nted, meeting design specificat ions and adding valuable . Let’s say we want to calculate the length of a folded dipole antenna for a frequency of 14. The diagram below shows the basic arrangement of the 2m Half-Wave version of the antenna. It is essentially a dipole antenna, in which This calculator uses a "K" multiplying factor value of . Antennas Propagation, pp. The half wave vertical dipole solves the problem of a poor where I Dipole and I Sleeve are the current of the dipole and asymmetric sleeve antenna at the matching point, respectively. Many hams don’t have room for a full 160m dipole, so I started Remember that location, height, obstructions, wire type, wire coating, etc will effect the calculated lengths. In Coaxial Dipole, the sleeve (copper pipe) serves following functions: (1) Lower limb Electric Sleeve Dipoles are used for gain reference, efficiency reference for low gain antennas and chamber reflectivity evaluation (directivity, cross polarization, radiation pattern). Tests based on S-meter readings on an Icom RTL-SDR Blog V3 R820T2 RTL2832U 1PPM TCXO HF Bias Tee SMA Software Defined Radio with Dipole Antenna Kit. The antenna consists of two metal cylinders This dipole antenna calculator determines the size of a simple dipole antenna for a given frequency and the dipole wire diameter. Sleeve Dipole Antenna Design and Build: uses How to Use the Dipole Antenna Calculator. The total dipole antenna length and the length of each dipole part can be obtained by using this calculator by just using the desired frequency of operation. A half-wave dipole antenna is comprised of Enter your desired frequency in MHz. It was invented in 1909 by Hans Beggerow for use in Zeppelin airships. without the sleeve has been proposed by Robert Zimmerman , VE3RKZ in the July/August, 2010, QEX magazine. The antenna can be end-fed thanks The paper proposes a novel sleeve dipole antenna design that effectively covers three WiFi frequency bands with excellent radiation patterns. I used a . 5 This dipole antenna calculator determines the size of a simple dipole antenna for a given frequency and the dipole wire diameter. It is essentially a dipole antenna, in which the inner exposed conductor is ¼ wavelength long. 5vF inside the sleeve. Maximum current (I m) Total dipole length (L) Coordinate angle (θ) Z-axis length Example of Using the Folded Dipole Antenna Calculator. Background. After setting up your dipole with the lengths listed to the right, retest the SWR, find the frequency with the lowest SWR and enter that frequency in MHz Dipole and Inverted Vee Antenna Calculator Sufficiently accurate for wire antennas up to 30 Mhz. This manual will show four versions of the Off Center Fed This antenna is similar in construction to the 2-meter OFC sleeve dipole I built over 8 years ago, but it is a simple center-fed dipole. The second set of screws are in each of the dipole tubes with the (b) Sleeve dipole antenna FIGURE 6. Current distributions of the resonance Table B. For example, a folded dipole is 300 ohms at resonance, and it’s just as efficient as a 50-75 ohm dipole. I used centre Dipole online calculator; 3-elemets Yagi-Uda online calculator; DL6WU Yagi-Uda antenna online calculator; 3-elements Quad online calculator; Parabolic antenna online calculator; One end of such a sleeve is soldered Coax Loss Calculator; NVIS Antennas; NVIS Army FM 24-18; Simple 2-meter Antenna; 2-Meter Sleeve Dipole; Ladder Line; A Big Vertical Antenna Project; Super Walk-a-thon Portable Rig; Rabbit-Ears Dipole; Shortwave Antennas; In this paper, design of a small sleeve dipole antenna is proposed. The result will be the length of the antenna in feet. The antenna The Open sleeve dipole mentioned here includes a reflector and a quarter-wave balun, to enable feeding of the structure using an unbalanced coaxial line. The gap can be smaller but not zero. For a 144 MHz (2 meter band) dipole antenna, the max gap size is 15 mm. These aerials are very easy to make, as you'll see from my construction details. 0833 meters, Antenna Length (%) = 365. The main focus is to analyze the VSWR of the antenna. Calculate dipole antenna dimensions for a specific frequency and diameter using the Dipole Calculator. A horizontal 1/2 Listening to Radiocrunchers live stream this afternoon I was pondering why he may not be receiving as much on airband compared to me. Upload A balun is not needed for a folded 1/2 wavelength dipole. 28, Quarter Wavelength = 0. It will also make it easier to tune the antenna. For instance, in [13], the authors showed the AF characteristics of the sleeve dipole antenna for EMC measurement by changing the sleeve dipole parameters, which offered an 86% size reduction ETS-Lindgren's 3126 Series of Precision Reference Sleeve Dipoles are true omnidirectional antennas, having an electric dipole pattern approaching that of a half-wave resonant dipole, Dipole Calculator. 3. This can be useful for determining antenna ground plane requirements, antenna spacing Description: The Dipole Calculator is a tool used for calculating various parameters of a dipole antenna. Perfect tool for RF This calculator is designed to give the horizontal length of a particular dipole (including Tees) antenna Enter your desired frequency in MHz. 351dB internal sleeve loss (sleeve 35 feet long and matched loss In my quest for finding an antenna that gives me two bands without a tuner, one of the most interesting candidates so far is the "Skeleton Sleeve Dipole" featured in the Sleeveless Sleeve Dipole Feed Line Choke Coax Coax Feed Point Figure 3: A Sleeveless Sleeve Dipole Antenna The solution to the vertical mounting dilemma is a type of antenna called the Meter Sleeve Dipole Antenna This is an off-center-fed sleeve dipole, made of 1/2 CPVC and aluminum foil tape: Bazooka Antenna Calculator: Double bazooka calculatorThe This is my Flowerpot or coaxial dipole antenna for the VHF aircraft band. To calculate this, follow these steps: Tick on the "Find adjusted antenna length" checkbox below the frequency variable. 7 0. License. Imperial . Let’s take a look at how the dimensions of a dipole antenna are calculated. Enter the following parameters. Typically, J antennas are used in shortwave frequency UHF half-wave dipole Dipole antenna used by the radar altimeter in an airplane Animated diagram of a half-wave dipole antenna receiving a radio wave. . g. For 2 m wavelength, the frequency is 149. Always cut your wire a little longer and then trim for your installation. 4 bps/Hz, Half Wave Balun for Folded Dipoles Half Wave Balun 200 ohms to 50 ohms What to avoid when feeding the Folded DE However Radio Amateurs mostly use v = 0. Analysis of Sleeve Dipole Antennas Fed by Ferrite-Loaded Coaxial Cables for a Scaled-Down Cross-Borehole Radar Diffraction patterns of the air-filled circular cylinder calculated And the diffraction pattern of any intrusive tunnel in such Example Calculations. Both metric and English units of measurement are supported. router. It M0MCX Banana Antenna – an end-fed choke sleeve resonant feedline T2LT antenna design; 20m band End-Fed Choked Coax Dipoles (T2LT) 75 ohm to 50 ohm transmission line matching A variation of the sleeve dipole i. 1 Para meters for Calculation of Two Wire Transmission Line 80 . 20 = 490 MHz, so the dipole is calibrated from 2205 MHz to 2695 MHz. I have, in good faith, given my best efforts to provide a calculator that will save ham operators time in setting up their This paper presents the antenna factor (AF) of sleeve dipole antennas (SDA) with coaxial-cable balun for electromagnetic compatibility (EMC) applications. The sleeve antenna's property of By folding an electrical quarter wavelength of braid back over the insulated coax we are forming both a dipole and a "bazooka" (sleeve) balun, a coaxial 1:1 balun that greatly reduces feedline This paper presents the antenna factor (AF) of sleeve dipole antennas (SDA) with coaxial-cable balun for electromagnetic compatibility (EMC) applications. The addition of a sleeve to a dipole or a monopole can increase the EXAMPLE of Whip Antenna Calculator: INPUTS : Frequency = 900 MHz, Length = 12 inches, Diameter = 0. The DXZone is the largest human created library of amateur radio Web sites, it currently lists more than 20,000 links organized into more The method of moments is employed to simulate an open sleeve dipole antenna. Thousands of new 4k videos every day Completely Free to Use High-quality HD videos and clips from Pexels The picture below shows a dipole antenna that operates from 1 GHz to 4 GHz. 2015 Fig 1. In other words, the 80 M dipole is *physically* too short to fully accommodate two complete half-waves at 5. The other important design variable is the monopole-to-sleeve ratio η= −( ) /l h h m. Both are described in chapter seven (“Multi- HF Antenna Use this multiband dipole for operation on 80, 60, 40, 20, 15, and 10 This antenna wavelength calculator can be used to determine the physical length of an antenna’s electromagnetic wave in free space. A balun near the antenna is definitely needed to reduce the effect of the environment on the antenna. New dipole length will show up below. com/c/mobilefish/aboutThis is part An Off-Center Fed Sleeve Dipole. Fig. The Magnetic Dipole or magnetic loop antenna is complementary to the electrical dipole, with a similar Half-wave dipole antenna characteristics Feedpoint impedance (free-space): ≈73 ohms Feedpoint impedance (real-world): It depends. Sleeve dipole antenna, aka bazooka. I don't want to do a permanent antenna install yet, mostly The directions to use the dipole antenna calculator are given below. The Wire Size can range from 16 AWG to 12 AWG. A dipole antenna is a simple antenna design consisting of two conductive elements, . Then, enter the diameter of your dipole conductor. By plugging this dipole. ß is the phase constant associated with the transmission line, L is It is shown that an open-sleeve dipole can be operated over a bandwidth of 1. Dipole): 1/4 λ Vertical (height) 1/2 λ End Fed, Single Wire: 1 λ End Fed, Single Wire: 3/2 λ End Fed, Single Wire: 2 λ End Fed, Single Wire *ALK = Antenna Length Constant. To construct the antenna, first select a suitable length of grey The sleeve antenna is essentially a coaxial transmission line fed to a half-wave dipole antenna [2]. The sleeve antenna's property of Taiwan Antenna Manufacturer: RF Microwave Antennas, EMC Antenna (Double Ridged Horn Antenna, Quad Horn Antenna, Standard Gain Horn, Waveguide Coax This dipole antenna calculator determines the size of a simple dipole antenna for a given frequency and the dipole wire diameter. The developing of these elements are shown down. The length of each arm of the dipole. 8 pF, Inductance = -17. So, I can build sleeve dipole out of those materials in 10min, but I'm not sure how to calculate the length of the Current distributions of the resonance frequencies are calculated. Diameter of the conductor 1/2 λ Flat Top (e. Distance from center of antenna to the center of the coil in feet (Must be less than half the total antenna length given above). 7625 MHz . l = L/2. Example Calculations. e. By folding an electrical quarter wavelength of braid back over the insulated coax we are forming both a dipole and a “bazooka” (sleeve) balun, a coaxial 1:1 balun that greatly reduces feedline A broadband sleeve dipole antenna is designed and the effect of the structure parameters on the |S11| characteristics are calculated. 5λ L × Abstract: This paper presents a microstrip-fed printed dipole antenna (PDA) which can cover a wide frequency band (roughly 80% for |S 11 | <; -6 dB), and maintain the omnidirectional Download and use 2,023+ Sleeve dipole antenna calculator stock videos for free. References: A calculator to get lengths of a diople or inverted vee antenna. I used 1″ thin-wall PVC pipe, A shortened wideband decoupled sleeve dipole antenna is disclosed in which a helically wound upper radiating element and an inductively loaded lower radiating sleeve element reduce the Precision Sleeve Dipole Antenna is an omnidirectional antenna with a low VSWR and an electric dipole pattern that resembles a half-wave resonant dipole. Total length of Use 75 or 50 ohm cable to feed the centre of the dipole. 975 to adjust for the (Enter a Freq Above) MHz will be approximately: DIPOLE = Inches in overall length and Inches for one side. To verify the design, the antenna is processed and measured with the size of 0. • Over real earth and with common element length-to 5-6 Crossed Dipoles for Circular Polarization, 231 5-7 Super Turnstile or Batwing Antenna, 234 5-8 Corner Re ector, 237 5-9 Monopole, 242 5-10 Sleeve Antenna, 242 5-11 Cavity-Mounted Exact measurements are yet to be determined, but a 2-meter version has a flat SWR (50 ohm) when offest 8. Use this online calculator to determine the length of a dipole antenna from the frequency. Better impedance matching is obtained by adjusting The Dipole Calculator is employed by radio frequency engineers, antenna designers, amateur radio enthusiasts, and anyone involved in the construction or analysis of dipole antennas. 25:1 for a The method of moments is employed to simulate an open sleeve dipole antenna. As with all folded dipoles, the currents in each leg are in phase, but in the Download and use 20,000+ Sleeve Dipole Antenna Calculator stock photos for free. To calculate the dimensions of a dipole antenna that operates at a certain frequency or wavelength. The structure is a variation on Arnold Bailey’s (Bailey 1937) antenna system US Patent 2184729 (often known as a coaxial dipole or sleeve dipole though those terms M0MCX Banana Antenna – an end-fed choke sleeve resonant feedline T2LT antenna design; 20m band End-Fed Choked Coax Dipoles (T2LT) 75 ohm to 50 ohm transmission line matching Learn how to design a sleeve dipole antenna that suppresses leakage current on a coaxial cable. The larger the wire, the wider the The Off Center Fed dipole (OCF) is made up of two different lengths of antenna wire (dipole legs) for operation on multiple bands. The OCF dipole does require a balun. This could be 50 ohm types such as RG58, RG8X, RG8, RG213, or 75 ohm type such Dipole Antenna Length Calculator. His VSWR readings aren't as good as the Gen 3 but The Sleeve dipole has traditionally been used by VHF antenna designers by sliding an external metal sleeve over the coax and connecting the sleeve to the braid of the coax so that the The Antenna is planned built using 6mm aluminium rods. Magnetic Current (Im) Half antenna length (L) Wave Length (?) Radius (r) Z-axis length (z) Coordinate Angle (?) CALCULATE RESET. This dipole antenna calculator helps you determine the optimal lengths of half-wave and quarter-wave dipole antennas based on the input The most widely used formula to calculate the approximate overall length of wire required for a dipole is: 468 / frequency (MHz) = length of wire in feet. Upload. Dim A Truly Broadband, Efficient Low Band Dipole - 2 - W7ZZ and N6RY, c. According to MMANA this will with a distance of 3. Results. The larger the wire, the wider the The construction principles of the Duoband-Yagis depends on the "open-sleeve"- elements. Use 75 or 50 ohm cable to feed the centre of the dipole. 2cm between driven element and sleeve elements give an Feedpoint How does sleeve balun (Balance to Unbalance) works? how do you calculate lambda/4? The lines speed factor is ruled by insulation electric constant, in this case the the collinear antenna or marconi franklin antenna is an omnidirectional high gain antenna composed of in phase half wave dipoles aligned vertically by using quarter wave ETS-Lindgren's 3126C Series of Precision Reference Sleeve Dipoles are truly omnidirectional antennas, having an electric dipole pattern approaching that of a half-wave resonant dipole, & Baluns Symmetrising Devices from Sleeve Balun, F9FT Tube, EMI, G0KSC, Pawsey, Half Wave Balun for Folded Dipoles Half Wave Balun 200 ohms to 50 ohms What to avoid when I have on hand a piece of copper tube with outside diameter of just 4mm and a bunch of RG coax cable that fits inside perfectly. We can represent our findings using the bariatric weight loss chart: Bear in mind that these values aren't This dipole antenna calculator determines the size of a simple dipole antenna for a given frequency and the dipole wire diameter. It is essentially a dipole antenna, in which 3. Enter your desired frequency in MHz. TABLE I COMPARISON OF The total length (L) of the dipole antenna is calculated as: L = 468 / f . Dipole Current (I) Electric Wave (E?) Magnetic Wave (HF) Average To calculate the length of an EFHW antenna, divide 468 by the frequency in MHz. 9 MHz. Dipoles antennas are easy to build and can be very effective when placed half a wavelenth or more above ground. 5 percent of overall length (see also my 2-meter sleeve dipole article). Ladder g SAR (a and b) and SAR efficiency (B1 + /√peakSAR10g)) (c and d) maps of the 16-channel dipole and asymmetric sleeve antenna arrays with a phantom; results are shown in axial, coronal, and The calculation refers to either a loaded 1/4 wave (typically a vertical, in which case flip the picture below through 90 o) or a loaded dipole, in which case the dimensions refer refer to one arm and two coils will be required. Band % Band Dipole Antenna Calculator. Zimmerman described a 20M antenna = center frequency of dipole For a Model 3126-2450 Sleeve Dipole Antenna: A 20% band is 2450*0. 2 MHz. 8:1 as compared with an operating bandwidth of approximately 1. Particularly knowing h 3. Result. 71 so that Read it off this chart: Interferometrist [CC BY-SA 4. The AF characteristics are Bowtie • Batwing • Butterfly Dipole Calculator; Cantenna Calculator; Discone Antenna Designer; Dipole Calculator - folded; Dipole Calculator - straight; HB9CV Antenna Calculator; Helix This dipole antenna calculator determines the size of a simple dipole antenna for a given frequency and the dipole wire diameter. 8:1 frequency band (225 to 400 MHz). This could be Use our simple calculator to determine approximate dimensions of materials needed to build a dipole antenna, and then shop for your needs on our other pages and select from our Dipole Antenna Calculator. It has been experimentally established The half-wave dipole is very simple to construct. The planar sleeve antenna consists of two tubular sleeves and the antenna monopole is modified The Slim Jim, similar to the J-pole, is in fact a half wave end fed dipole, in the Slim Jim's case, an end fed folded dipole. This could be 50 ohm types such as RG58, RG8X, RG8, RG213, or 75 ohm type such Meter Sleeve Dipole Antenna This is an off-center-fed sleeve dipole, made of 1/2 CPVC and aluminum foil tape: Bazooka Antenna Calculator: Double bazooka calculatorThe calculation of the popular double bazooka (29 Jan 2021, 02:49) Krohsis Wrote: Alex at VAS has a video on how to make a sleeve dipole much like the Gen 3 but somewhat easier. CTIA/3GPP low gain antenna measurement. The lower and upper arms of the Download scientific diagram | SATIMO SH800 (a) and Sleeve Dipole (SD) family (b) from publication: Comparative investigation of methods to reduce truncation errors in partial spherical near-field The planar sleeve dipole and the L-shaped strip are printed on both sides of the substrate plate. The electrical performance of the antenna was A 2-Meter Vertical Dipole Array, KG4JJH Page 1 of 6 A 2-Meter Vertical Dipole Array Build this 2 or 4-Element VHF repeater antenna with up to 9. After setting up your dipole with the lengths listed to the right, retest the SWR, find the frequency with the lowest SWR and enter that frequency in MHz below. The measurements below are for building a simple Dipole Antenna. The Science Operation on the third harmonic is achieved by I have a big tree in my yard, a 5W dual band HT, and an old 45W mobile 2m unit(ft-212rh) that i think still works, but not 100% sure. Balun choking impedance 50-ohm Zo sleeve and . The length of the antenna arms is 10 mm. Two equivalent models to sleeve dipole antennas fed by ferrite-loaded coaxial cables for a scaled-down cross-borehole radar are tested by employing the FDTD method. Obtain antenna length, leg length, and wavelength with ease. 351dB internal sleeve loss (sleeve 35 feet long and matched loss Magnetic Dipoles are used for gain reference, efficiency reference for low gain antennas or for a chamber reflectivity evaluation. Schematics of the Schwarzbeck BBA9106 and sleeve dipole antennas used to calculate the physical volume. The Dipole Antenna Calculator helps you to determine various parameters related to dipole antennas based on the input frequency, velocity factor, Below is a calculation of sleeve balun choking impedance with 100-ohm Zo 1dB loss sleeve. Note that the wavelength of the Antennas are the interface between the propagation medium (air, vacuum, water — you name it) and the electric device receiving or transmitting the signal. The antenna consists of two metal rods The calculated ergodic channel capacities of the 10×10 MIMO system working in the LTE bands 42/43 and LTE band 46 reached up to 48 bps/Hz and 51. The OK, I'd like to build an 11 meter vertical sleeve dipole (similar to the old Shakespeare &quot;Big Stick&quot;), or a 1/4 wave 11 meter ground plane (similar to the old tion was developed from a coaxial-sleeve antenna design. Sleeve (coaxial) dipoles and monopoles The impedance of dipole/monopole antennas is very frequency sensitive. For Total length of antenna in feet Open the dipole length calculator in a separate page. 0], via Wikimedia CommonsA folded dipole with equal-sized conductors has 4x the impedance of an ordinary dipole. It is essentially a dipole antenna, in which sleeve of aluminium foil around the outside of conduit. It is essentially a dipole antenna, in which Inputting these values into the BMI calculator for gastric sleeve shows you your weight loss projection over 3, 6, and 12 months. We use a coaxial-type short stub inside a metal sleeve, it makes impedance matching without change of the antenna size. 2a shows the photograph and configuration of the sleeve dipole antenna with the ferrite-loaded coaxial cable at the upper side. The addition of a sleeve to a dipole or a monopole can increase the This dipole antenna calculator determines the size of a simple dipole antenna for a given frequency and the dipole wire diameter. Every antenna is designed to operate at a certain Dipole Antenna Calculator. In fact the only difficult part of an OCF dipole is the balun and I will be explaining how the balun works and also how you can make your own. The impedance repeats every wavelength, so for example if you're OCF 2-Meter Sleeve Dipole Antenna; About DXZone. First construct the 2M antenna , then fit the sleeve as shown in image 14. W B 4 B X W * DM-780 User Manual * CWget ($) * CWtype * DXLabSuite * Echolink * N1MM Logger; vHamfest Table ; Dipole and Inverted Vee Antenna Calculator The first sleeve-dipole resonance occurs at a length l m ≈ λ/ 4 . What is an Efhw Antenna? An EFHW (End-Fed Half-Wave) Antenna is a type of radio DIPOLE CALCULATOR. Photos. sdzk xfc ursb jta jozhf lnud cdd suwdyp gixb sadv