SteppIR Performance From Two Wires

If you spend any time on the bands these days, it won't be long before you hear the term "SteppIR" being used by enthusiastic aficionados of big, rather costly to buy antennas.

SteppIR antennas are indeed very nice antennas, and extremely popular in the more affluent parts of society.  They are also, of course, not the only 3-element yagis available, just, perhaps, the best.

A SteppIR 3-element yagi.

But can SteppIR-like performance be attained for a lot less than the current (March 2013) manufacturer's list price of $1826 (product number 00203)?  The answer is, surprisingly, an emphatic yes!

Now, I am not comparing like with like, obviously, so the comparison only holds for the 20m band for the moment.  SteppIR give their gain figure for the 3 element yagi as 7.4dBi at the 20m band.

But, what happens if I add a reflector element to my existing delta loop antenna?   The question is important because my delta consists of a sub-£100 system comprised of wire, a fishing pole and a 4:1 balun.  The second element costs less, because it's just a loop held up by another fishing pole with no need for any balun or cable to connect anything.  What's more, the base of the antenna is only at 2m above ground.

The modelled answer is a gain almost exactly the same as the 3-element SteppIR - I kid you not.  I ran WSPR tests to see how the as-yet imperfect set-up I have does really deliver.

Yours for very little money: a 2 -element delta, peak gain about 7.4dBi.

 
And it does!  The signal received stateside (direction of fire) increased by a mean of 5.5dB for that limited test, which you must remember is just adding another piece of wire that's a little longer than the driven element but not tuned yet, and a spacing that is only roughly worked out on normal formulae, and not optimised for peak gain yet.  A fair wind also led to some variation in performance due to a swaying fishing pole.

On limited SSB tests, a station in Tennessee was pushing a very respectable 54 using two elements, but was down to a miserly 3/1 on just one element.  Noise is dramatically down with two elements as well, indicating a respectable F/B ratio (probably about 10dB.)  I also had a nice session on 10m PSK into Latin America using the double delta.

So, whilst we are not quite at SteppIR-busting gain, we're pretty darned close without any optimisation at all.  For a few pounds/dollars, we've got a 20m beam that is easy to put up (and down!), doesn't need a tower and gives us about an extra 'S' point on the signal.  What you do need is a fairly reasonably-sized garden to accommodate the two elements for this band.  You will also need a means of moving things around if you want to change the direction of fire, in which case, the image above shows what must be by far the easiest way of doing it, though suspension from a decent tree is also possible if you have one tall enough.

Unfortunately for me on a wild hillside, I will now need to make a double delta, single support antenna that can also be easily retracted, redeployed and rotated - quite a tall order!