Downloads & Software. NEC Monitor Software. Take full control of your NEC solution with our specialized control, calibration, and adjustment software. Find firmware updates, drivers and software downloads for NEX-3.
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?
Nec Antenna software, free download For Mac Windows 7
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
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)
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
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.