N2EA wrote:
> There are situations where the steppIR is inappropriate. If I wanted
> a stack, for example, I would go with fixed monobanders and optimized
s> pacing. In a large multi-multi station, the amount of control wiring
> could become a maintenance problem; plus, the variable length antenna
> is unnecessary when you have multiple antennas on multiple towers.
Right, and multiple SteppIRs on multiple towers would be far more expensive
than multiple monobanders on multiple towers. Makes no sense. However, for a
single-tower SO2R or M/S/2 contest station, a stack of SteppIRs is a
reasonable choice (at least, it was for me.) If a second large tower can't
be built, there simply isn't room for 3 separate stacks of monobanders on
one tower. A stack of SteppIRs is a reasonable alternative to a stack of
tribanders in such a case, though the theoretical perfomance edge of the
"monoband" SteppIR design versus one of the modern optimized multiband
designs is certainly debatable and may not have meanigful impact on contest
scores.
It's not a simple comparison. A SteppIR stack will probably offer somwhat
better performance over a wider bandwidth, particularly on 20m, and
certainly better SWR matching. Element spacing on the 4-el SteppIR is
perhaps a bit more of a compromise than it is on some of the tribander
designs, especially on 10m, where the SteppIR's F/R isn't great (the boom is
too long.) The tribander has a significant advantage in terms of simplicity
and instant tuning (no waiting to change bands), and I can tell you that
sharing three SteppIRs between two radios is a very complex task (I'm in the
process of writing software to do it.) A stack of high-quality tribanders
will be somewhat less expensive than a 3-stack of SteppIRs. In the end,
though, I figured there would be less susceptibility to interstation
interference with the SteppIR stack. I've had some interference issues with
tribanders in my SO2R station, and have been able to reduce the interference
by using monobanders. I felt the SteppIR design would be the better choice
in that important category.
So, a lot depends on what you plan to do with the antennas...
73, Dick WC1M
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