https://consumer.steppir.com/product-category/horizontal-antennas/4-element-antenna-products
https://www.eham.net/reviews/view-product?id=1833
Thoughts on the SteppIR 4 Element Yagi
Copy source is: http://www.k6if.com/steppir/steppir_4el.html
A Contester’s View
By Dan Levin, K6IF and Marty Levin, W6BDN – April 12, 2004
The Antenna
The 2 element SteppIR is a short boom, driven plus director, design. Two element yagi’s with a driven element and a director, rather than the more traditional driven element and reflector, deliver higher gain but much narrower bandwidth. L.B. Cebik produced a wonderful piece on this topic, which you can see here. The executive summary is that if you are willing to live with very narrow bandwidth (for example, a driven director yagi with a 0.08 wavelength long boom on 10 meters might have a 2:1 SWR operating bandwidth of 250 kHz and gain within .5 db of its peak over less than 500 kHz), you can get quite a bit more gain from a two element array (peak gain of 7.29 dbi vs. peak gain of 6.25 dbi for “traditional” designs). In the case of the SteppIR, since the antenna can be tuned at will (and even automatically), bandwidth is pretty much irrelevant. That makes a driven-director 2 element configuration reasonable, and thus allows a very high gain antenna on a short boom. Hence Fluid Motion’s claims that their two element yagi delivers performance similar to that of traditional three element antennae.
| C-31XR Gain | SteppIR Gain | C-31XR F/B | SteppIR F/B | |
| 10 Meters | 7.4 | 8.14 | 21 | 8 |
| 15 Meters | 6.3 | 7.98 | 22 | 20 |
| 20 Meters | 6.0 | 6.88 | 20 | 21 |
In summary, the SteppIR uses more boom than the C-31 on each band, despite the fact that their total boom lengths are the same. That longer boom delivers more gain, as you might expect. Interestingly, on 10 and 20 meters, the SteppIR’s advantage is only about .7-.9 db. On 15 meters, for reasons that aren’t completely clear to us, the SteppIR delivers a healthy 1.7 db more gain. The C-31 delivers about the same gain on 15 and 20 (.3 db difference). The SteppIR delivers about the same gain on 15 and 10 (.15 db difference).
Conclusions
Our goal in this exercise was to inform our own decision about what antennas to install at our single tower contest station. We have limited space, and hope for the best possible performance given our constraints… We currently use Force 12 yagi’s, including a C-31XR as our main high band antenna. We were very interested to know how this new fangled antenna would compare to our tried and true C-31XR.
Our conclusion is that, mechanical issues aside, the SteppIR 4 element yagi is a serious contender. It offers gain about equal to that of a five to six element long boom mono-bander on 10 and 15 meters, and does quite well on 20 too. Front to back, especially on 10 meters, is quite a bit less than any of the antennas that we compared it to.
There are serious questions in our mind about the mechanical reliability of an antenna with motors. These antennas are also quite expensive, a fair bit more than their direct competitors. But those issues aside, the SteppIR is clearly worth a hard look.
