Replacement CDs or downloads of EZNEC v. 3.0 are no longer available. Please see "Upgrading to v. 6.0", below, for upgrade information.

My program was working, but now it fails with the message 'Runtime error 339: Component dwsbc36.ocx or one of its dependencies not correctly registered, a file is missing or invalid'.

Several spyware removal programs incorrectly identify dwspy36.dll, a file used by dwsbc36.ocx, as spyware and recommend its deletion. (See "What is dwspy36.dll in the EZNEC program directory", below, for information about these files.) The message occurs when the file is deleted. Restoring EZNEC functionality requires restoring dwspy36.dll. Some spyware removal programs allow this, or it might be restored with an undelete utility. If neither is possible, running the EZNEC installation will recreate the file. The current version of EZNEC no longer uses these files, but v. 3.0 does. So version 3.0 users should direct any spyware removal programs to not delete them.

When I try to install EZNEC I get the message 'C:\WINDOWS\SYSTEM32\AUTOEXEC.NT. The system file is not suitable for running MS-DOS and Microsoft Windows applications' or other message involving AUTOEXEC.NT.

This is most often caused by the Windows XP Service Pack 2 (SP2) installation deleting (for unknown reasons) the Autoexec.nt file which is required to run 16 bit programs. The EZNEC installation program is intentionally an older type in order to keep download size smaller and updates simpler, and requires 16 bit (DOS-type) operation during part of the process. (EZNEC itself doesn't.) You should be able to solve the problem by locating a copy of Autoexec.nt in your C:\Windows\Repair directory (the directory might be C:\Winnt\Repair on systems upgraded from Windows 2000) and copying it into your Windows system directory C:\Windows\System32 (or C:\Winnt\System on some upgraded systems). If you need further assistance or this doesn't fix the problem, please let me know.

Will EZNEC 3.0 run under Windows XP? Vista? Windows 7?

Yes to all, but not 64 bit versions of those operating systems. EZNEC pro v. 3.0 requires some modification to run under Vista or Windows 7. EZNEC pro users should contact me for additional information. No EZNEC v. 3.0 program type will not install on 64 bit operating systems. See next item.

Will EZNEC 3.0 run under 64 bit operating systems?

No. If you have a 64 bit operating system (such as the 64 bit versions of XP, Vista, or Windows 7), you must upgrade to the current version of EZNEC or request a refund. There is no problem running EZNEC v. 3.0 on a 64 bit computer, as long as the operating system is 32 bit. Except for versions specifically identified as 64 bit, Windows XP and Vista are 32 bit systems.

Can EZNEC 3.0 use the antenna description files I created with an earlier version?

Absolutely! EZNEC 3.0 can even read and translate ELNEC (.EN) files -- just include the extension (.EN) when specifying the name of the file to open. Older versions of EZNEC can also read and use files written by EZNEC 3.0. EZNEC 3.0 uses the same plot file format as EZNEC v. 2.0, and can display plots saved by ELNEC or any version of EZNEC.

If I buy the CD-ROM version, does the CD-ROM have to be in place when running the program?

No. All necessary files are installed on your hard drive. The CD-ROM is needed only for installation. If desired, the CD-ROM files can be copied to a hard drive or Zip drive and the program installed or re-installed from there.

Where's the manual?

The manual is an integral part of the program. With EZNEC 3.0 running, In the EZNEC 3.0 Control Center (the main window), click Help on the menu bar, then choose Contents to view the manual. You can also open the manual to the relevant topic from many places in the program by pressing F1. This sort of manual is often called an "on-line" manual, but people sometimes mistakenly misinterpret that term to mean that the manual is on the Internet. It's not.

Is it possible to get a printed manual?

A version is now available which you can load into a word processor and print yourself. If you purchased EZNEC 3.0 on a CD-ROM after about September 1, 2000, you'll find it in the Printable Manual directory on the CD-ROM. Otherwise, you can download it. Clicking here will take you to the page where you can get more information. No printed manual is available.

What's the EZNEC 3.0 segment limit?

The limit for EZNEC 3.0 is the same as for earlier versions, 500 segments maximum. This allows approximately 25 wavelengths of wire, or 50 beam elements. The professional versions of EZNEC 3.0 accommodate up to 10,000 segments.

Will EZNEC 3.0 overwrite my ELNEC or DOS EZNEC program?

No. EZNEC 3.0 will not affect these programs in any way. You can even install it in the same directory if desired.

What's the difference between the upgrade version and full program?

There are no different "upgrade" and "full" or "new" versions. There's only one version, and it's a complete, independent program which doesn't require any other program in order to function. The only difference between a new purchase and an upgrade purchase is the price; the program is the same.

Is there any difference between the download and CD-ROM products?

The installed program is exactly the same -- the only difference is in the format of the files used for installation. The download product is a single executable file, for convenient downloading. It expands and creates temporary files during the installation process, which are deleted when the installation is complete. The CD-ROM contains several files. Although it also creates some temporary files during installation, they aren't as large as the ones created by the download version. Consequently, the download product requires somewhat more disk space (roughly 15 MB) during installation than the CD-ROM product. Otherwise, there's no difference. Once installed, the programs and disk space requirements are the same. You may need to re-install EZNEC in the event of a hard drive failure or change to your computer system, so you should always keep either the CD-ROM or downloaded file. If you don't have any way to back up the downloaded file on some medium other than your primary hard drive, you should order the CD-ROM (with or without the download) to protect against loss of the program in the event of a hard drive failure.

Doesn't being a Windows program make EZNEC 3.0 slower than the older DOS versions?

Actually, EZNEC 3.0 does its calculations about 20% faster than previous versions. The calculating engine is a separate FORTRAN executable file which doesn't make any Windows calls (except to communicate calculation progress to the main program), and the FORTRAN compiler used for the EZNEC 3.0 calculating engine has better optimization than the one used for previous versions. All other operations, such as graphics, are as fast or faster than earlier versions. One of the slowest operations in DOS EZNEC was calculation of wire connections each time a wire coordinate was changed. This process has been optimized and moved to a FORTRAN DLL, and runs something like 20 times faster than before. If you do experience very slow operation of EZNEC 3.0, please see the next item.

My EZNEC 3.0 runs extremely slowly. Why?

Some versions of McAfee Antivirus sofware, when running in the background detection mode, can cause extremely slow operation of EZNEC 3.0 calculations. This problem can suddenly appear when the antivirus software is updated. Apparently, the antivirus software intercepts and analyzes the communications between the calculating engine and the main program. These communications are numerous and frequent, so the rather slow analysis process by the antivirus program greatly slows EZNEC operation. The only certain solution is to disable the background checking feature of the McAfee software while runningEZNEC 3.0. So far, this has been reported only with McAfee version 4, and it appears that version 6 might not have this effect on EZNEC. This isn't certain, however.

What is dwspy36.dll in the EZNEC program directory?

Some people have expressed concern about dwspy36.dll and wonder what its function is. This file is a "subclassing" control, part of a third-party utility package called SpyWorks, purchased from Desaware, a highly respected company which is well known to the Visual Basic programming community. This package allows functionality beyond that provided by Visual Basic or normal Windows programming but despite its rather sinister name is not "spy" software. When you attempt to reduce the size of graphical windows below a certain point, EZNEC limits the minimum size. This size limiting isn't possible with Visual Basic (except with "bounce-back" type operation), so a technique called "subclassing" is used. EZNEC intercepts the normal Windows message sent when a window is resized and directs it to code that limits the window size. The SpyWorks control (dwsbc36.ocx, which uses dwspy36.dll) allows this functionality. (It's apparently so named because of its ability to "spy on" -- intercept -- messages sent to and from the Windows operating system by applications during normal operation.) Some versions of EZNEC installed dwsbc36.ocx and dwspy36.dll in the EZNEC program directory; other versions installed them in the Windows system directory instead. An increasing number of spyware removal programs misidentify dwspy36.dll as spyware and delete it, which caused EZNEC to crash. Because of this problem, EZNEC was modified at version 4.0.5 to use a recompiled version of a similar DesaWare product, rather than dwsbc36.ocx and dwspy36.dll. V. 4.0.9 and later use an entirely different and newly compiled control. Version 3.0 continues to use the DesaWare files, so version 3.0 users should direct any spyware removal programs to not delete them.
No version of EZNEC does keystroke logging or any other type of user activity recording, reporting, or Internet connection. For more information about the SpyWorks package, see http://www.desaware.com/SpyWorksL2.htm, and for more information about subclassing, see http://www.desaware.com/Subclassing.htm.

What language is EZNEC 3.0 written in?

The interface portion of the program was written in Microsoft Visual Basic 6.0. It consists of about 50,000 lines of source code, not counting comments. I wrote every line, and it took about two years of essentially full time work to develop the Windows version. The calculating engine is a modified version of the public domain NEC-2 program. It's written in Fortran, and incorporated as a separate executable file.

Where can I get more EZNEC models?

The CD included with the 20th and later editions of the ARRL Antenna Book has several hundred EZNEC models of a wide variety of antennas. While specially created to work with the EZNEC ARRL program which also comes with the Antenna Book, they're also standard EZNEC files which work normally with EZNEC 3.0. Even without the EZNEC files, the ARRL Antenna Book is a bargain, but the files make it even more so. Also, check http://www.cebik.com for models and other good information.

Upgrading to v. 6.0

All users who purchased an earlier version of EZNEC are entitled to a substantial discount from the full price when upgrading. To upgrade via the web, you'll need your Customer ID number which was sent by email or mail shortly after v. 6.0 introduction. If you want to upgrade and don't have your Customer ID number, email w7el@eznec.com to request it. Please don't purchase a new program at full price and request a refund.

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