NEC/MININEC-based Software Vendors:
- EM Scientific: "New" MININEC Free "Expert MININEC Classic" software
- EZNEC/EZNEC+ and EZNEC Pro (W7EL)
- NEC-Win Plus, NEC-Win Pro, GNEC "Nittany Scientific"
- Orion Microsytems: NEC4WIN MININEC Software "NEC4WIN95"
- Super NEC "SuperNEC" NEC2/UTD combo
- 4NEC2 Free NEC-2 software with excellent GUI
- TLDetails & MoxGen by Dan Maguire AC6LA (MultiNEC not available)
- MMANA Free software based on MININEC from DL2KQ-EU1TT
- CocoaNEC Free NEC software for the Mac OS-X Tiger operating system by W7AY
Other MOM-based Software Providers:
- WIPL-D Method of Moments software
- ANSOFT Designer 2D+ Code for Patch Antenna Design (Free Student Version)
- Zeland Software IE3D 2D+ Code for Patch Antenna Design
- Antenna Design Freeware from Meyers Engineering
- MOMIC Method of Moments Interactive Code
- NEC-BSC NEC Basic Scattering Code (Ohio State)
- YagiCAD 5.1 free Yagi-specific Windows software by VK3DIP
- Yagi Modeler Applet online applet to simulate Yagis by W9CF
FEA-based Software Vendors:
- HFSS 3D Antenna Structure Simulator
Antenna Structural Analysis Software:
NEC/MININEC Organizations and Resources:
- The (Unofficial) NEC Archives (WB6TPU) Free Software!
- NEC-2 information Users Manual for NEC and other information
- L.B. Cebik's Antenna Site (W4RNL) Hundreds of Antenna Articles!
Other RF and Antenna Software
Learn How Antennas Work!
Linear Dipole - set length to 0.5 (half-wavelength dipole) and notice that the impedance is near 73 ohms. Radiation pattern shown is typical figure-8 pattern. When a half-wave dipole is close to ground, the impedance is lowered to near 50 ohms. Thus a perfect match to 50 ohm cable.
-set length to 1.27 wavelength. This is called an Extended Double Zepp antenna and produces the maximum gain possible from a simple center-fed dipole. Notice that the radiation resistance (impedance) is about 90 ohms. This antenna can be matched to 50 ohms by using a series inductor. Half of this antenna is 5/8 wave and is a common length for 2m mobile antennas. The 5/8 wave antenna is typically fed against a ground plane (car roof) and is usually matched with a tapped inductor.
-set length of 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 radiation resistance (impedance) close to 100 ohms. The patterns of these are made up of many lobes (cloverleaf pattern).
How do antennas produce gain?
- dB, dBi, dBd What is dBi? What is dBd? What is an isotropic radiator? Part 1 in a series from LB Cebik W4RNL
- Where does the gain come from? Part 3 in a series from LB Cebik W4RNL
Lincoln Amateur Radio Club Antenna Class
Links to Software and other information
- 4NEC2 Free NEC-2 software with excellent GUI
- Agilent AppCAD Transmission Lines and more
- MIMP Motorola Impedance Matching Program (select zip file and download)
- NEC Tutorial - Learn how to create NEC input files
- NEC User Guides (HTML & PDF)
- Smith Chart resources (articles, software and charts)
- Antenna Modeling Software from Dan Maguire AC6LA (MultiNEC, Moxon generator, TLDetails, etc.)
- KB0YKI's Radio Zone (online J-Pole Designer, online Yagi Designer, the "Copper Cactus" double J-Pole)
- PCAAD 2.1 Software to help design wire, horn and patch antennas - by Dave Pozar
LPCAD - Log Periodic CAD
NEC Model Library
The following files and links point to NEC/AO/YO models of various Ham antennas that I have simulated and/or tested over the past 30 years as an antenna designer. The NEC files may be used with any of the NEC-2 or NEC-4 programs such as 4NEC2, GNEC or cocoaNEC, however some of them with tapered elements may only be simulated accurately by NEC-4 or other MININEC-based software. These models will indicate in the CM lines if they need to use NEC-4 or 4NEC2. These models have varying degrees of accuracy. Some may be very close to actual performance. Others may only be an estimate. They are for you, as the experimenter, to use and improve. This list will grow as I check each file before uploading, so check back often. Have fun!
- W3LPL Yagi Designs for 40, 20, 15 and 10m
VHF NEC Models:
- 28DX a 13.4 dBi low backlobe Yagi for 144.2 on a 12' 6" boom
- 215DX a 16.35 dBi low backlobe high-performance Yagi for 144.2 MHz (metric dimensions)
- 216CP (AO file) a very experimental RHCP 2m beam with 12.3 dBic gain and single point feed
- 216CP (NEC file) - updated 2-4-06 - improved axial ratio & VSWR
- 23DF a 3 element Yagi for 2m Foxhunting (7.7 dBi & 40 dB F/B)
- 25FB a 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 (10.4 dBi & 34 dB F/B)
- 27FB a 7 element 8' 6" boom Yagi for 2m Foxhunting (11 dBi & 36 dB F/B)
- 6m_3el_yagi an 8.1 dBi low backlobe Yagi for 50.1 on a 6' boom
- 6m_4el_yagi a 9.8 dBi Yagi for 50.1 on a 12' 6" boom (use in 4NEC2)
- 6m_moxon a 6.2 dBi "Moxon rectangle" for 50.1 MHz
The VHF antennas shown above include the "raw" element lengths. That is, 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. To convert these raw lengths into actual lengths used when passed through the center of metal booms, you need to add a correction factor, based on whether the element is insulated and passes through the center of a metal boom, or is shorted directly to the metal boom with a clamp.
If the element is insulated when it passes through the metal boom, the correction factor is approximately 1/4 the diameter of the boom. For example, for a 36" (raw length) insulated element passed through the center of a 1" metal boom, the correction factor is 0.25", so the actual length should be 36.25" when built.
This information on stealth antennas was presented at a Lincoln ARC meeting in March 2006.
Bike Helmet 2m Antenna Mount
How I mounted a 2m HT whip antenna to my bike helmet (or how to really look stupid on a bike)
Show APRS activity in Lincoln (current)