TheW8IO / WB0DGF Antenna Site

1. Library Of Mmana Antenna Files File
2. Mmana Nec

(30 March 2015)

NEC Software for Yagi Design

The MMANA-GAL analysis was then repeated at a 3% higher frequency of 150 MHz to compensate for the analysis not correctly allowing for enamel insulation and wire end effects. To do this, reload the initial antenna dimensions file saved earlier and in the Geometry window, ensure that the Frequency is now set to 150 MHz. Antenna Pattern File Library Below are ZIP files containing large collections of pattern files for RFI Base station antennas. Each pattern file type is compatible with various coverage simulation software packages available today. Click on the links below to download the corresponding ZIP file of your choice.

Note: K6STI's AO and YO software no longer available. His older versions will not work in Windows 7 and 8.

NEC/MININEC-basedSoftware Vendors:

• EMScientific:'New'MININEC Free'Expert MININEC Classic' software - badlink?

• EZNEC/EZNEC+andEZNECPro (W7EL)

• NEC-WinPlus, NEC-Win Pro, GNEC 'NittanyScientific' - now out ofbusiness

• OrionMicrosytems:NEC4WIN MININEC Software'NEC4WIN95' - do not order fromKAGI?

• SuperNEC 'SuperNEC' NEC2/UTDcombo

• 4NEC2 FreeNEC-2 software with excellent GUI - new web site 3-1-13

• NEC2++ from Tim Molteno (discussionforum)

• AutoEZ,TLDetails&MoxGen by Dan Maguire AC6LA

• MMANAFreesoftware based on MININEC from DL2KQ-EU1TT

• CocoaNECFreeNEC software for the Mac OS-X Tiger operating system by W7AY

OtherMOM-based Software Providers:

• WIPL-DMethod of Moments software

• ANSYSDesigner 2D+Code for Patch Antenna Design (FreeStudentVersion - no longer available)

• MentorGraphics Software (was IE3D) 2D+Code for Patch Antenna Design

• AntennaDesign Freeware fromMeyers Engineering

• MOMICMethod of Moments Interactive Code - notavailable?

• NEC-BSCNEC Basic Scattering Code, ESP -Electromagnetic Surface Patch Code andothers(Ohio State)

• YagiCAD6.2.0freeYagi-specific Windows software by VK3DIP

• YagiModeler Applet online applet tosimulate Yagis by W9CF

FEA-basedSoftware Vendors:

• ANSYSHFSS3D Antenna Structure Simulator

AntennaStructural Analysis Software:

NEC/MININECOrganizations and Resources:

• The(Unofficial) NEC Archives(WB6TPU) FreeSoftware!

• NEC-2informationUsers Manual for NEC and other information

• L.B.Cebik'sAntennaSite (W4RNL) Hundreds ofAntenna Articles!

Other RFand Antenna Software

(links updated 18 Feb 2013)

Learn HowAntennas Work!

LinearDipole - set length to 0.5(half-wavelength dipole) and notice that theimpedance is near 73 ohms. Radiation pattern shown is typicalfigure-8pattern. When a half-wave dipole is close to ground, the impedance isloweredto near 50 ohms. Thus a perfect match to 50 ohm cable.

-set lengthto 1.27 wavelength. This is called an Extended Double Zeppantenna and produces the maximum gain possible from a simple center-feddipole. Notice that the radiation resistance (impedance) is about 90ohms. This antenna can be matched to 50 ohms by using a seriesinductor.Half of this antenna is 5/8 wave and is a common length for 2m mobileantennas.The 5/8 wave antenna is typically fed against a ground plane (car roof)andis usually matched with a tapped inductor.

-set lengthof dipole to multiples of 1/4 wave on each side (e.g. 0.5, 1.5,2.5, etc.). Notice how these lengths produce an radiationresistance(impedance) close to 100 ohms. The patterns of these are madeup ofmany lobes (cloverleaf pattern).

How doantennas produce gain?

• dB,dBi, dBd What is dBi? What is dBd? What is an isotropicradiator? Part 1 in a series from LB Cebik W4RNL

• Wheredoesthe gain come from? Part 3 in a series from LB Cebik W4RNL

updated 17 Jan 2006

LincolnAmateur Radio Club Antenna Class

Library Of Mmana Antenna Files File

Links to Software and other information

• 4NEC2 FreeNEC-2 software with excellent GUI

• AgilentAppCAD Transmission Lines and more

• MIMPMotorola Impedance Matching Program (select zip file and download)

• NECTutorial - Learn how to createNEC input files

• NECUser Guides (HTML &PDF)

• SmithChartresources (articles, softwareand charts)

• AntennaModelingSoftwarefrom Dan Maguire AC6LA (MultiNEC, Moxon generator, TLDetails, etc.)

• KB0YKI'sRadio Zone (onlineJ-Pole Designer, online Yagi Designer, the 'Copper Cactus' doubleJ-Pole)

• PCAAD2.1 Software to helpdesign wire, horn and patch antennas - by Dave Pozar

updated ?

LPCAD - Log Periodic CAD

Now availablefor Windows 7 OS!

LPCAD version 3.4 is nowavailable! LPCAD 3.4runs fine underWindows 2000, XP, Vista and Windows 7. Please emailme at rgcox2 (at) gmail.com for details.

updated 18 Feb2013

NEC ModelLibrary

The following files and links point to NEC/AO/YO models of various Hamantennasthat I have simulated and/or tested over the past 30 years as anantennadesigner. The NEC files may be used with any of the NEC-2 or NEC-4programssuch as 4NEC2, GNEC or cocoaNEC, however some of them with taperedelementsmay only be simulated accurately by NEC-4 or other MININEC-basedsoftware.These models will indicate in the CM lines if they need to use NEC-4 or4NEC2.These models have varying degrees of accuracy. Some may be very closetoactual performance. Others may only be an estimate. They are for you,asthe experimenter, to use and improve. This list will grow asI checkeach file before uploading, so check back often. Have fun!

Links:

• W3LPLYagi Designs for 40,20, 15 and 10m

VHF NECModels:

• 28DX a 13.4 dBi low backlobe Yagi for 144.2 on a 12' 6' boom

• 215DXa 16.35 dBi low backlobe high-performance Yagi for 144.2 MHz (metricdimensions)

• 216CP (AO file) a very experimental RHCP 2m beam with 12.3 dBicgain and single point feed

• 216CP(NEC file) - updated 2-4-06 - improved axial ratio & VSWR

• 23DFa 3 element Yagi for 2m Foxhunting (7.7 dBi & 40 dB F/B)

• 25FBa 5 element 4' 4' boom Yagi for 2m Foxhunting (9.4 dBi& 34 dB F/B)

• 26FB a 6 element 6' 6' boom Yagi for 2m Foxhunting (10.4dBi & 34 dB F/B)

• 27FB a 7 element 8' 6' boom Yagi for 2m Foxhunting (11dBi & 36 dB F/B)

• 6m_3el_yagi an8.1 dBi low backlobe Yagi for 50.1 on a 6' boom

• 6m_4el_yagi a9.8 dBi Yagi for 50.1 on a 12' 6' boom (use in 4NEC2)

• 6m_moxona 6.2 dBi 'Moxon rectangle' for 50.1 MHz

• LP50-108-16 (NEC file) a Log-Periodic Dipole Array for 50-108 MHz, 8 dBi, 30 dB F/R on 6m, 12' boom

The VHF antennas shown above include the 'raw' element lengths. Thatis, the element lengths are those used with a wood or plastic(dielectric)boom or supported above or below a metal boom with an large insulator.Toconvert these raw lengths into actual lengths used when passed throughthecenter of metal booms, you need to add a correction factor, based onwhetherthe element is insulated and passes through the center of a metal boom,oris shorted directly to the metal boom with a clamp.

If theelement is insulated when it passes through the metal boom, thecorrectionfactor is approximately 1/4 the diameter of the boom. Forexample,for a 36' (raw length) insulated element passed through the center of a1'metal boom, the correction factor is 0.25', so the actual length shouldbe36.25' when built.

(updated 16 July 2013)

Commentsare welcome!

contactRoger: email to WB0DGF @ ARRL.NET

or

rgcox2(at) gmail.com

Roger Cox - Spring Lake, MI

I wanted a quick & easy to install high-power multiband wire antenna for field-day and temporary operations and I’ve been hearing a lot about End-Fed Halfwave antennas lately.

So I recently purchased the EFHW-8010-2K from Myantennas.com which is a company that I’ve come to trust for their high-quality components, workmanship and excellent CMC products (more on those in a future post).

The EFHW-8010-2K is the heavy-duty QRO version which supports up to 2kW ICAS power levels. It is 39.6m long and is resonant on 80 through 10 meters, while the construction really is top-notch. Perfect for the abuse I’d put it through if need be (EMCOMM, DXpeditions, Contestingetc).
However, after reading through all the End-Fed “hype” I became curious and wanted to see how this antenna actually performs. Well, at least theoretically through software simulation. I wanted to see what differences it has, if any, to a random wire, to an Off-Center Fed Dipole (OCFD / Windom) and to a classic dipole antenna. So I fired up MMANA-GAL, and looked in the antenna library for a ready modelled EFHW file, albeit, there wasn’t one!…well there wasn’t one like mine that is.

Mmana Nec

MMANA-GAL is a popular antenna design, analyzing and modelling software tool, that is relatively easy to learn and use. It is arguably simpler, and in some cases more powerful, than other antenna modelling software such as EZNEC or 4nec2, and that is why it has become popular for relatively simple antenna modelling. It comes in two versions, the basic version which is free, and the PRO version which is paid. You can download MMANA-GAL Basic from here: http://gal-ana.de/basicmm/en/#18

After searching online, I couldn’t find a single reliable model of an EFHW in MMANA. There were several variants, however, none were accurate to my antenna’s specifications. So I decided to design and build my own model from scratch, which is a pretty simple thing to do in MMANA-GAL.

My EFHW is cut for 80 meters, and the manufacturer states that it has low VSWR on every amateur band, all the way up to 10M. Using MMANA-GAL I modelled it in an inverted-V topology since this would likely be the most common topology one would use, and it’s very simple to change it (ie to a sloper, horizontal wire etc).

You can download the MMANA “.maa” model file that I created for the EndFed Halfwave 80Μ-10M Antenna (EFHW-8010.maa) by clicking on the image or click here to download.

Feel free to use the antenna model file and customize it to your specific needs in MMANA-GAL. It’s very interesting to simulate this antenna’s performance and radiation pattern in various topologies & installation setups, and to compare it to other similar antennas.

Additionally, below are some screenshots of the far-field plots and antenna layout from my model (click to enlarge):

The radiation pattern is very similar to a standard dipole on the first resonant frequency, and equallyvery similar to an Off-Center-Fed-Dipole on the resonant harmonic bands. I read somewhere that essentially there is no such thing as an EFHW, and that it actually is an extremely off-center fed dipole. Well, I can confirm this by looking at the radiation pattern, and its electrical characteristics. Regardless of how you want to call it, it is essentially a dipole fed from one wire end with an impedance transformer to match the feed-point impedance to the transmission line impedance, that’s about it!.

Generally speaking EFHW antennas seem to be a good compromise antenna due to their increased practicality of feeding at the wire-end, which is their significant advantage. However expect performance similar to (or slightly worse than) an OCFD/Windom, nothing more.

An interesting thing you might notice when looking at the 3D radiation pattern on the base frequency, is that only about 1/4λ of the wire closest to the feed point is doing most of the radiating, with the peak current occurring around the center. While the far side (remaining 1/4λ) is not doing much at all. On harmonics, this whole phenomenon re-occurs every 1/4λ of the harmonic frequency until about the center.

You also might need to be a bit careful with the hardware used at the feed-point when operating under high power QRO. There is a serious risk of arcing and voltage breakdown, due to the very high-voltage developed.

This is due to the wire end impedance of a 1/2λ dipole being close to 2450Ω, which is the feed point impedance of an EFHW (ie at the secondary of the impedance matching transformer).

So by using OHM’s law V = √(P x R), if we feed the antenna with 1kW RF out and with the EFHW feed point impedance of 2.45kΩ, then we will see 1.57kV developed at the feed point (ouch!).

How to crack a 3 digit combo lock. The 8010 from Μyantennas is rated at 2kW ICAS so it shouldn’ t be a problem with 500W+ CW, but still, it’s scary when you think about it 🤯

Generally speaking, EFHW antennas seem to be a good compromise antenna due to their increased practicality of feeding at the wire-end, which is their significant advantage. However expect performance similar to (or slightly worse than) an OCFD/Windom, nothing more. There is no pot of gold at the end of this rainbow! 😀

73’s to all! de Andy SV1DKD