YS can be used with any electrical design software. It simply assumes that you have the ability to create the electrical design you desire and can translate that into a tubing taper schedule for the construction of your elements. That element taper description is what YS will analyze. The antenna design process is an iterative one, where you will pass the element dimesions back and forth between YS and your electrical design software a few times to arrive at the final solution.

The following procedure assumes the use of Yagi Optimizer (YO), but will be essentially the same for any other program.


1. Design an antenna that you like with "YO" using the taper schedule that you have. Keep this design intact for reference. You will need the monotaper lengths later. Use the YO "Elements" selection to view these lengths. You will want to record the lengths and the element positions on the boom just in case you get "brain fade" and replace the original "YO" file with the new dimensions you are going to get from YS.
See the Element Design page for an alternate method, where you first create a rough mechanical design with YS.

2. Create a new YS data file using the dimensions you obtained from "YO" and run the element stress analysis. If your "YO" model has a special section to describe the element to boom connection, delete it when creating the YS file. This section is not mechanically accurate. Nor is it critical. Most elements fail in the tubing adjacent to the boom connection or another joint.

3. If the elements are not strong enough (I.E. Safe wind speed too low), then examine the elements to see where the weak point is. The weak point is at the inner end of the element section that shows the highest stress.

To correct the problem you must do the following:

Shorten the section that is weak and lengthen a section that is stronger to remain at the same resonant frequency OR insert a smaller diameter piece into the inner end of the weak section. This will do two things, 1) shorten the weaker section, thus lowering the bending moment (and stress) at the inner end of the singlewall section and 2) increase the wall thickness (double wall) at the original weak point, thus lowering the stress because there is now more material here to carry the load.

To insert a piece inside a section, select the ADD SECTION option. YS will place a section there that has the same diameter and wall as the previous section and a length of 1.0. Press <E> to edit the new section and enter the actual dimensions. After the new section is dimensioned, shorten the outer section length to obtain the original resonant frequency.

Inserting a piece will make the most dramatic improvement, and is preferred because it will maintain or reduce the surface area. The first choice will increase the area if the only stronger sections to lengthen are the larger diameter ones and these types of changes are relatively insignificant as you will see.

You will have to make many compromises that are less than optimum based on the existing lengths of your tubing and the extent of your scrap pile.

 4. Go back and make a new modified "YO" file (use a different name) with the stronger dimensions and run it. When it comes up on the screen, it may not be exactly like the last antenna that you fell in love with, but don't worry, you won't have to design it all over again because you saved the original element positions and monotaper lengths. All you have to do is press "E" and restore the original dimensions. Now you should have the same YO antenna with the new taper schedule. To get this, YO had to adjust the tips, so you'll have to revisit the design in YS to see if YO is trying to break your tips!
If you are using a program to manually alter the electrical design, make your tuning adjustments to the innermost section (nearest the boom). That way the element survival speeds will be least affected.

Repeat this cycle until you run out of beer, or material in your scrap pile or the sun comes up and you have to explain it all to your XYL.


YS users report that the ability to retain element resonant frequencies, while altering the mechanical design is excellent.