Paul McMahon VK3DIP

News and Releases

What is YagiCAD




Installing and Removing YagiCAD


Genetic Optimisation In YagiCAD

YagiCAD Tips, Tricks, and Examples




YagiCAD News


Interim Bug Fix 6.3.2 May 2022, thanks to Arturas LY5FOX for pointing out

that 6.3.1 had reintroduced a problem with regions where the decimal separator

was other than a “.”, and testing out this bugfix.

Until I can do a full release for it a new version 6.3.2 which plays nicer with

other decimal separators can be downloaded from here: www.yagicad.com/YagiCad632.zip

just extract and or copy the new exe over the top of the existing 6.3.1

 Yagicad.exe, feedback as always welcome.

New - Adding a custom element type to Yagicad here

New YagiCAD6.3.1

Changes 6.3.0 to 6.3.1 February 2022

1.       New options on Genetic Optimiser to select which elements and which aspects of the elements to evolve. Also some internal changes to the genetic

          algorithms to make them less likely to go cancerous/ produce bad yagis.

2.       Four new element types; a rounded end folded dipole, an octagonal loop, a bent X (think old J Beam multi element), and a variable bow tie that can go

from a classic skeleton slot, to a dual quad, to the aformentioned bow tie. New examples in examples directory to illustrate these including;

the classic RSGB 6 over 6 skeleton slot fed array, a shortened homage to the JBeam MDM series, a short loop yagi, and a classic DL6WU 20 element

          yagi with rounded folded dipole and dual reflector.

3.       Bug fixes to the scaler routines to make them more consistent with the more complex elements, option added to allow extra params to be treated as

          either lengths or spacings.

4.       Added an Element Type Browser under the help menu, a pdf version for all elements is saved in the executable directory.

Changes 6.2.7 to 6.3.0 December 2021

1.       Major under the covers change, Element models now generated from data file ElemLib.ycl loaded at start up.

          Also added new models for bent dipole Up, Down, Forward, Back, plus split Multi type into 3.

          It will be much easier to add new element prototypes in the future, only editing of ElemLib file will be required no actual coding.

          ElemLib is actually just a text file and has comments on how to add/change element cells, but very little error checking in this

          version, and any changes to order etc. will cause problems with Yagi files saved in previous YagiCAD versions. Use caution if you play with this.

          The current version should be backwards compatible. I will add further new element models etc. as I get comments/suggestions/input from users.

          Many areas rewritten to utilize ElemLib, so there may be bugs I haven't yet found, please report any you find.

2.       Added three new example files illustrating the use of a bent element, Original K6STI 5 element FM Broadcast band with bent back(V) driver,

          UA9TC 11 element with bent forward reflector, and DB7YBN GTV70-11W using a bent back driver with a larger inner section. With these bent

          dipole elements     the length is the distance between the two end tips, the first parameter is the distance the ends are bent back, forwards,

          up, down, and the second parameter is the length of the inner section of the element. Display headings on grid now dynamically changed to suit

          the highlighted element. Take care with bent elements especially if doing genetic optimising it is possible for elements with sharp angles etc.

          to be generated and the genetic algorithm does not do AGT etc. to validate each model before breeding.

3.       Bug fixes to some of the multi units(mm, M, ", wavelength etc.) support to make it more consistent.

4.       Genetic routine rebuilt so now runs work in true background so fore ground operation is smoother etc., but may be a bit slower.

5.       Changes to options to reflect element library changes, plus support new nec engine options including the previous nec2++,

          a new (supplied in this distro) MiniNec Command line exe , and NEC4 command line (exe not supplied, must be sourced elsewhere).

          The different engines have different areas of strengths and weaknesses, Mininec handles some geometries better, nec2++ is faster,

          Nec4(if you have paid LLNL for it, and copied the command line exe into the exe folder) is more powerful than nec2++ but is slightly slower.

6.       Changes to some of the graphs to make them more readable eg. expanded VSWR scale, and extended Convergence/Average Gain which by the way is

          also now supported in the mininec command line engine. With the new element lib it is even more important to do these model tests and

          understand what they are saying, as it is actually easier to now produce a sub optimal model if you are not careful. Remember there is

          no such thing as a free lunch, and if the results look too good to be true then they probably from a bad model.

7.       Changes to the TANT style temperature calculations to add a more accurate integration engine (same as used in NEC2), but note this still uses

          both some somewhat arbitrary assumptions, and if you want to compare results with other TANT's, you need to set the same assumptions.

          Also don't forget this is ultimately limited by the precision available in the (only a couple of decimal places in a

          rounded/truncated logarithmic number) pseudo printed text output from the NEC engines, rounding etc. errors do take place.

          If we wanted higher accuracy than this it would have to be done in the NEC engines itselves, or at least get full precision/pre-log

          results for powers etc. direct from the engine not via a limited textual interface.

8.       Tested with Win11 all seems OK though some minor visual bleedthrough effects in grid display.


Changes 6.2.6 to 6.2.7 August 2019
1.     Beta version of multi band optimization in OWA Genetic tool, please report any problems.
2.     Bug fixes to fix occasional crashes due to even numbers of segments.
3.     Corrected problem with reference yagi gain, now shows in same units as main gain.

Bugfix YagiCAD 6.2.6

November 2018 6.2.6 Bugfix.

1.       Fixed bug with options not saving/loading correctly. replacement 6.2.61 exe (zipped) Here

Changes 6.2.5 to 6.2.6 August 2017.

1.       Added mm (MilliMetres) as a units option.

2.       Some minor changes to limits in antenna temperature figure of merit calculations. 

3.       Added limited export to EZNec format file. Thanks to Roy Lewallen for his permission and for the file details. Only the very basics are exported to try and limit problems. Please report any issues to me.

4.      Redo of boom correction support, can now edit in either length or length+bcf columns, now need to use options menu to vary custom BCF.

5.       Updated version of Nec-Tie included, fixed some bugs with loads support in MiniNec, also added import from EZNec format files. Thanks again Roy. See NEC-TIE page for more info.

6.       A number of minor cosmetic changes.


YagiCAD 6.2.5

Changes 6.2.0 to 6.2.5 catchup release August 2015.

1.       Updated TEE match calculations to be in line with equations in latest version of "Playing with Matches"


2.       Changed Antenna temperature tool nomenclature to be as per Rainer Bertelsmeier's Effective Noise Temperatures of 4-Yagi-Arrays for 432 MHz EME in DUBUS 4/87. 

3.       Added a number of other possible element material types such as 6063-T832, and 6061-T6 Aluminium alloys as per common usage.

4.      Added Antenna notes window, via Tools menu, for multiline/longer notes on a design.

5.       Included stand-alone NEC-TIE app in main YagiCAD directory, also available from Tools menu, that can import NEC(most nec2 and 4nec2 nec), YW(.yw), YO(.yag), MN and AO (.ant) style files and amongst other  things convert them (if they are Yagi's) to a monotaper yagi and save in YagiCAD (YC6) format. Getting all those designs from the ARRL antenna book etc. should now be easy. Also includes native double precision mininec, and antenna viewer. Version 1.0 of NEC-TIE comments/bugs welcomed. See NEC-TIE page for more info.

6.       A number of minor cosmetic changes.


April 2014

1.       Changed internally and for export to have Yagi boom along X axis to align with common usage.

2.       Added antenna temperature tool to toolbox which does a basic noise calculation based on the DUBUS article by Rainer Bertelsmeier, DJ9BV “Effective Noise Temperature of 4- Yagi-Arrays for 432 Mhz EME”. This produces similar results to the TANT program by YT1NT.

3.       To validate the antenna temperature figures, or for other post processing uses there is now also an export option for a far field table in an appropriate format for TANT.

4.      Added the ability to have two more folded dipole element variants, these are similar to the existing folded dipole however they are in the plane of the boom rather than perpendicular to it. One variant is laid down forward ie. Drive is closer to the reflector, while the other variant is laid backwards, ie. The driven side is closest to the first director. These configurations are sometimes known as LFA. See the included example model 13e23cmLFA.YC6 as an example of what can be achieved with this configuration.


5.       Added option on tools option form to select calling a NEC engine via a command (or BAT) file or directly (default.). The default direct call to nec2++.exe is faster and automatically handles whatever the number of segments. The command file option however allows the use of other standard nec executables if you have a favorite. Examples for some of these are included in the necrun.cmd file in the root install directory. (Unused ones should be prefaced by a REM). I have not tested this with NEC4 (as I don't have access to it) but it should work. Please let me know if anyone finds any problems with this.

6.       A few other mostly cosmetic tweaks.


November 2013

1.       Added ASCII text export of model for codes that don't read nec files.

2.       Bug fixes around boom correction factors, now entry of custom BCF is always a number less than 1. Also clarified for the built in correction factors that one is for the element insulated from the boom case (Ins), and one is for the element connected to the boom (Con) case.

3.       Rejig of the Gamma, Tee, Omega etc. matches to align with the ARRL and other interpretation of how these       matches work. In particular now based on the full driven element impedance rather than half as specified in Balanis textbook. My local tests with NEC2 models of Gamma agree that, while no simple model is particularly close to what you get from the more complex NEC2 model, those with full element impedance are closest. Also at least now YagiCAD should give the same answers as ARRL GAMMA program.

4.       Changes inside the genetic algorithm to try to detect and kill "cancerous" yagi's where gain is unreasonably high which can mask real improvements in rest of gene pool. Unreasonable high gain usually due to, elements with too close spacings, and other known model limitations within NEC2.

4.       A few other mostly cosmetic tweeks.



New Version 6.1.8

April 2011

1.       Added 4NEC2 specific export support under file/export menu. 4NEC2.nec file will contain symbolic variable   extensions as supported by 4NEC2 to assist with easily changing Yagi variables like antenna height.


New Version 6.1.7

February 2011

1. Added limits concepts into Genetic Optimisation.Can set a hard, soft, or no limit for each Target value. Hard = reject designs that better this target Soft = keep but limit score, None = do not limit score.

2. Added Boom length as a parameter in Genetic Optimisation. eg setting Boom Length Limit to a particular length, with a hard limit type will force only designs with Boom Length less than this value to be considered.

3. Changed default install directory to be not program files to avoid problems with Windows Vista and 7 and admin rights.

4. Minor bug fixes with units in matching sections.

5. Released companion XLS spreadsheet for tapered elements.LeesonTaper.xls in main install directory.


Version 6.1.6

January 2011

Bug fix release.

1. Fixed a bug that had got into the Genetics bits that was causing unpredicatble results.

2. Added config file for frequency band edges. If found "banddata.txt" in main directory is used rather than default Australian ones. see example file for format.

Version 6.1.5

March 2010

Changes 6.1.5

  1. Replaced Fortran based NEC2SX/DX engine with Open Source C++ version of NEC2.(Compiled using free MS C++ 2008 Express)
  2. Added new element models of folded dipole and multi-element
  3. A few minor bug fixes.

Added YagiCAD Tips Tricks and Examples Page Here

Minor release 6.0.2

December 2009 


·        Added support for country specific decimal point value, and in particular "," in stead of "." Thanks to Noel ON5 Ui

·        Minimum of VSWR graph in Overall now 1 rather than 0.Thanks to Scott VK2AET

·        A couple of minor bugs fixed.

·        Install package which registers file types and creates shortcuts etc.


New Version 6.0 with Quads and Quagy’s

December 2009 


·       Re-written using the free development package Microsoft VB.NET Express 2008.  More Windows standard interface, now requires MS.Net runtime 2.0 (for pre Win XP) or 3.5 (for post Win XP) rather than VB5 runtime as per YagiCAD5.x

·        Removed YagiCAD classic engine, now only NEC2 available but choice of SX (single precision as in YagiCAD5) or new DX Double precision.

·        NEC2 engines recompiled with larger limits now allowing up to 40 elements, 2000 segments, or 100 non-ideal wires, whichever limit is reached first.

·        Still only a single driven element, but it can now be in any position in antenna from first to last. Ie antennas of a single driven element are now possible, eg dipole, as well as ones with multiple reflectors.

·        Elements can now be either a simple dipole, or a square quad shape. Elements can be set individually to each type allowing for various combinations giving standard Yagi’s, Quad’s, or Quagies

·        Dimensions used for display and editing can now be set to be in Metres, Inches, or Wavelengths. All internal calculations and saving of data is done in Metres.

·        New file extension “.YC6” used to save antennas with new features,   YagiCAD can still open/read “.YAG” files but not save them as other than “.YC6”.

·        The YagiCAD6 exe now accepts a filename as a command line parameter enabling “.YC6” and “.YAG” files to be associated in windows with the exe for double clicking on a file and opening in YagiCAD.

·        New Yagi Viewer menu to give 3D view of antenna model under design.

·        Simplified and expanded genetic Optimization subsystem. Configuration of options now done by selecting options on a page rather than editing a text file. New options include improved weighting process with optional reference/normalization to either the ancestor antenna or some idealized target.

·        Improved Model tests with segment convergence now graphed within the application to show effects of increasing segments, and in addition inclusion of the standard Average Gain Test.

·        A number of other visual tweaks, oh and yes it’s still free, however it is a .0 release after a major rewrite so there may well be bugs etc. I haven’t yet found so take some care to make backups etc.


New Version 5.2 with Genetic wideband optimisation

December 2007

New in version 5.2

·        Genetic wideband multi parameter optimisation.

·        Some new OWA base models.

·        A number of minor fixes and tweaks.


Updated Version 5.1   

September 2006

New in version 5.1

·        More Match Options.- Hairpin, Omega, Capacitive.

·        Many minor fixes and tweaks.


Initial Windows Release Version 5.0     

November 2003

Version 5.0

·        Native 32 bit Windows full Graphical interface.

·        Optional use of included NEC2 for calculations.

·        Copy and paste to other Windows applications.

·        Export models and data to Nec 2, and CSV.



Re-Release of Version 4.2 on the internet.  

July 2003


Initial Release of Version 4.2   

April 1991

·        Directivity as well as Gain/FB/Sidelobe etc. optimization now available.

·        Initial entry of data proceedure reworked to be easier to use including new clear option if you really want to start from scratch, plus defaults for all entries.

·        ESC key now exits/aborts most processing and returns you to the menu. No more waiting if you just asked for the analysis of the wrong thing.

·        Improved Error handling/reporting. Instead of errors flashing past on line 25, a pop up box will tell you what is going on, and you will have to hit a key to continue.

·        Several bug fixes.



What is YagiCAD.


Yagicad is a fully integrated analysis and design package primarily intended for VHF yagi aerials.


With Yagicad it is possible to enter a base design from scratch or use one of a number of saved well known designs. This design can then be optimised or scaled to suit particular requirements. Once this has been done a matching unit can be estimated and overall performance characteristics can be calculated and displayed graphically. Also available are radiation patterns and hardcopy print-out of results. Allowances in an analysis can also be made for element cross sections other than simple circular ones, as well as boom mounting techniques.

















Unlike earlier versions of YAGICAD which were released under a shareware banner (not that I ever made any money out of them) this latter version 5.0 and on are presented free. I offer it to the worldwide community of antenna experimenters in part repayment for the advice and invaluable input I have received from them over the years. It is my hope that it will be useful to them and also help to introduce new people (and especially radio amateurs) to the joys of antenna experimentation. I do however retain the copyright, and if someone wanted to include this program in some book or software collection I would appreciate being at least asked first. I can be contacted at the address below. Similarly if you have any comments or feedback please feel free to email me. I can't guarantee a speedy reply but I probably will get there eventually



 Its a small(strange) world.

 Back in 1987 I wrote the first version of YagiCAD based on some earlier programs I had done for one of the pre IBM PC machines called a Microbee.. As this was pre-internet days I released YagiCAD via the medium that was available at the time which was Compuserve. There were several versions, up to the last one I did in 1991 which was YagiCAD version 4.2 (yes not 4.1). Up to version 4.2.  these early versions used the wonderful tool from Microsoft called Quick Basic that I had purchased during a trip to America, this was initially version 3 but for later versions I updated to 4.5.

To be honest I then pretty much forgot about it because:

 1/. The motivation for the program was to fill a gap between cookbook style programs and the more full blown (mini)NEC style ones that, at the time, needed much more machine grunt than I had access to, a 386 was a powerful machine in those days. This lack of machine grunt very quickly went away, and NEC style programs became much more practical, even if still not very friendly.

2/. I obtained very little feedback and there seemed to be a large number of competing offerings.

3/. I got distracted with Work and Family etc.

 So I was very surprised in June 2003 to come across, while looking for something else on the Web, a file called YagiCAD, which sure enough was my program, but strangely it was version 4.1, a quick search with Google etc. yielded several sites which mentioned the program but again all were version 4.1.

Anyway, after some effort to find a machine with a 5.25 inch disk drive on it to read some old backups, I confirmed that indeed the latest version that I did back in 1991 was version 4.2.  As far as I can figure someone back then must have got version 4.1 off Compuserve, and subsequently not got the 4.2 version, perhaps the 1st of April build date put them off, but anyway at some stage that 4.1 file was loaded onto the internet and it has gone on from there.

 Anyway I tried to contact some of the sites to let them know about the later version but had variable success.

 Having got the idea that some people obviously liked the program, I got enthused about YagiCAD again and subsequently produced a windows version released in late 2003. This version 5.0 release as well as being windows based also took advantage of the drastic increases in machine performance to add a version of the full NEC2 calculation engine as an option.  The program retains the original very much simpler original YagiCAD engine for backwards compatibility, but unless you have a very slow machine it is best to use the NEC2 one. For comparison the original engine used only one segment per element, the NEC2 one runs fine on most current machines with more than 30 segments per element.


Installation and Removal


Automatic Install – Setup.exe

If you use the version with the Setup program then there is nothing to do other than run the setup exe, and answer the questions. This will do all the items indicated below for the manual setup except for the installation of the dot net framework if required. There will be a menu item on the start menu to uninstall if required or the control panel add remove programs process can be used. Note when installing to Vista you may need to be logged on as an administrator.


Manual Install. – YC60dist.zip

Save all the files of the distribution in a suitable directory. The EXE’s, OPT, GEN, and RTF file/s should all be in this directory. The saved antenna models can be in the same directory or elsewhere if more convenient.


If you don’t already have the MS DotNet framework installed this can be downloaded from the Microsoft.com website and installed as per instructions. For PC’s with operating systems prior to Windows XP the file you are looking for is Dot Net Framework 2.0 Redistributable, for those with Windows XP or better the 3.5 version is the way to go.


You can create an icon on your desktop to run YagiCAD by right clicking and dragging the exe to the Desktop and selecting create shortcut here.


You can also in a file view window select tools/folder options/file types and associate the “.YAG”, and “.YC6” extensions with YagiCAD.exe.  Or alternately simply double click on a “.YAG” or “.YC6” file and select program to open with as being YagiCAD.exe.


Manual Uninstall,

YagiCAD makes no changes to the registry (other than associating .Yag/.Yrc files), nor (apart from the DotNet runtime mentioned) are there any files installed outside the original directory created. So just delete the directory created for the install if you don’t want it anymore.


From version 5.0 on YagiCAD is now a windows application and should work on all 32 bit windows versions 98 and up. There are some limitations with the dot net framework, as mentioned earlier dotNet 2 is the latest version stated as usable on 98/NT/ME etc, dotNet 3 comes preinstalled on Vista.


Screenshots of Version 6.














Download Link

YagiCAD 4.2


YagiCAD 5.1


YagiCAD 5.2


YagiCAD 6.02 Just the files


YagiCAD 6.02 Setup Program


YagiCAD 6.1.5 Just the files


YagiCAD 6.1.5 Setup Program


YagiCAD 6.1.6 Setup Program


YagiCAD 6.1.6 Just the file


YagiCAD 6.1.7 Setup Program


YagiCAD 6.1.7 Just the files


YagiCAD 6.1.8 Setup Program


YagiCAD 6.1.8 Just the files


YagiCAD 6.1.9 Setup Program


YagiCAD 6.1.9 Just the files


YagiCAD 6.2.0 Setup Program


YagiCAD 6.2.0 Just the files


YagiCAD 6.2.5 Setup Program


YagiCAD 6.2.5 Just the files


YagiCAD 6.2.6 Setup Program


YagiCAD 6.2.6 Just the files


YagiCAD 6.2.7 Setup Program


YagiCAD 6.2.7 Just the files


YagiCAD 6.3.0 Setup Program


YagiCAD 6.3.0 Just the files


YagiCAD 6.3.1 Setup Program


YagiCAD 6.3.1 Just the files




If you have any feedback on YagiCAD please send me a message at mailto:Ihatespam@yagicad.com

Please note you need to replace “Ihatespam” with my callsign to get my actual email address.