>
>Several have mentioned potential failure points for the SteppIR
antennas. I
>haven't heard about many failures. In fact, I can't think of any. There
are a
>fair number in us by now. How often are failures encountered?
>
>Kim N5OP
About 7 years ago, a good friend lent us his early-model 3-element
20-10m SteppIR for the winter season, to see how it would fare in this
extremely windy QTH. It worked fine, with no problems, so MM0WNW and I
broke both our piggy-banks to buy a new one for ourselves.
The SteppIR that arrived was almost a different antenna! SteppIR had
made many improvements in the 15 years since production began, and many
of the problems with earlier models would not apply to an antenna bought
new today. Among the major, obvious improvements were:
1. Fiberglass tubes: thicker, stronger, more accurately made, more
weather-resistant surface finish, smoother internal finish, and more
permanently assembled using glue-lined heatshrink sleeves.
2. New moldings for the motor/element housings.
3. Completely new controller (SDA100) with improved firmware and
lightning protection.
That was 5 yours ago, and our later-model SteppIR has performed well and
reliably since then. We couldn't have put up a larger antenna anyhow,
and a multi-monobander on the same boom length would have had a much
greater wind loading. In short, the SteppIR concept delivers the best
available performance at this particular QTH, and gives us six bands.
It still isn't perfect, though. At the time we purchased the new
antenna, the documentation was failing to keep up with the production
changes, though hopefully that too has changed by now. Another major
failing is the tacky method of connecting the 13 drive wires for the
stepper motors - a 10-cent screw terminal block inside a short length of
plastic pipe. This summer's job is to install a waterproof plastic box
with a waterproof multipole connector, and I would recommend new owners
to do that on Day 1.
With hindsight, would we buy that same 3-element 20-10m SteppIR again?
YES.
Would we buy a different model with longer, trombone elements? Not quite
so sure. We would probably stick with what we do know, that the simple
straight elements for 10-20m work well and reliably.
And finally, 6m. Although SteppIR do offer an extra director for 6m, I
found the performance was quite poor, and was also badly affected by
rainwater on the fiberglass tubes. Both of these problems were due to
the SteppIR reflector being way too far behind the driven element. Being
firmly committed to using our 3-element SteppIR on 6m, I developed a
new, re-optimized design which now includes a dedicated 6m reflector:
http://files.qrz.com/k/gm3sek/DSC_0008.JPG This new version is
nothing extraordinary; it simply works as a good 4-element Yagi
should... which was something I could never feel about SteppIR's own 6m
design. Forward gain according to NEC is about the same as SteppIR were
claiming, but the radiation pattern is now much cleaner and performance
on 6m is no longer sensitive to rainwater. Claims based on stations
worked are always anecdotal, but anecdotes in large enough numbers do
begin to gather some force: in its short lifetime this modified antenna
has already worked 100 countries on 6m (with no help from F2) and a few
moonbounce QSOs as well. Full construction details are in the latest
newsletter from the UK Six Metre Group (www.uksmg.org).
73 from Ian GM3SEK
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