SteppIR Element Length Study
My friends know that as soon as I get something, I have to rip it apart and find out how it works, or how I might be able to make it better. With the ability to individually adjust the physical element lengths, the SteppIR may be an antenna experimenter's dream come true...or nightmare (only kidding).
That being said, I have built and present here four EZNEC studies for the 3 element SteppIR for 17 meters. These studies are:
I have also made available a link to download each EZNEC file for each study. Models are models, but contacts are contacts. I encourage all SteppIR users to experiment with these files and their own antennas and let me know their impressions. Over the next few weeks I will do the same and update these pages. BTW, all measurements are shown in inches. The default settings are taken from the controller setup/default screens.
download EZNEC file for this study: 17m1 factory default
update: 8/20/2004: this model works great in the real world. I have reports that this design is about 1 s-unit better on transmit, and 1.5 s units better on receive from my location.
update:2/24/2005: I have now worked with the improved model several months and I can definitely tell you it is hotter on transmit/receive and consistently shows a lower swr. If you look at the difference between the two settings, notice that the driven element length DOES NOT CHANGE! It stays at 304 inches for both antennas. The pattern and impediance of the antenna are affected through changing the lengths of the director and reflector and NOT the driven element. Twice the front to back and a bit more forward.
download EZNEC file for this study: 17m1 improved
download EZNEC file for this study: 17m1 factory 180 mode
download EZNEC file for this study: 17m1 improved 180 mode
There is a lot of confusion regarding the 6 meter performance of the antenna. I have the 6 meter passive element installed. Over the past year, Fluidmotion has reversed the placing of the 6 meter passive element. They used to put it between the driven and reflector elements and the main lobe was in the opposite direction. Now, they want it between the driven and director elements and it is directional in the normal way. The default settings in my controller were set to placing between the driven and reflector elements, so I had no way of knowing what the correct lengths were. Through a couple of hours of trial and error, and some input from a few owners, I have managed to figure out an improved model. Beware of trying to adjust the SWR on 6 meters by changing the length of the driven element. Sure, you can bring it way down, but you will also reduce by almost one half the forward gain of the antenna. If you have a question on this, email me and I will send you the files to show this. Just take my word for it as you know I am a genius in these things...hi hi....
Here is the model for 6 meters: 6 meter improved.ez. You will notice that when you try to load this file, eznec will give you an error message about the passive element. Since we cannot change its length, we have to stick with what we have.
I encourage users to send me their comments via email at k6sgh @ cox.net (i have purposely not put a link here for the email because of the spammers that seem able to get such email addresses.)