Re StepIR antennas:
Many good points made in this thread about F/B and gain but it seems to me a
couple of additional points still need to be made.
In 42 years of hamming, I've never owned a beam (or run high power) so my
comments need to be taken in that context. Only used verticals, dipoles,
Zepps, etc. However, if I do decide to get a beam, based solely on my
reading of many months of emails on this reflector, the last thing I would
want to consider is an antenna that utilizes TRAPs, stubs and other gizmos
to achieve resonance and whose metal radiators are exposed to the elements
while also presenting a relatively larger wind resistance and thus
requiring a relatively stronger/larger tower structure.
Recently, I did get a close up look at the StepIR demo unit. It was very
interesting seeing how the element length is adjusted by physically moving
within the fiberglass case. Frankly, it didn't take me long to conclude
StepIR is likely to be more reliable mechanically than all the metal, traps
and other gizmos used in most competing approaches. I'm not saying StepIR
will never need maintenance. But am saying that it doesn't make sense to me
to speculate that StepIR would be less reliable than the well known
unreliability of metal corrosion, traps and other gizmos.
For instance, quite a few recent threads on this reflector have addressed
things like radiator corrosion in recent months. Wonder how much corrosion
StepIR radiators will have since they are housed within fiberglass tubes?
Seems to me, the StepIR mechanical approach is probably more reliable and
will require less maintenance than all the traps and exposed metal many/most
ham antennas depend upon today. Why, even the traps on my vertical need
attention every few years. So, now that StepIR has announced a 34 ft tall
40-10M vertical (2 octaves!) using a single element whose length is adjusted
mechanically within a fiberglass tube, I am very interested. Bet that
vertical will be more reliable than competing, exposed metal, multiband
verticals that use traps, stubs and other techniques.
Another point I don't recall seeing mentioned so far in this thread is that
the StepIR competes not only with a traditional beam, it also competes with
log periodic designs. It doesn't just cover only the ham bands between 14
MHz and 54 MHz, it covers ALL frequencies in between! Seems like a real
breakthrough when compared to all the metal a log periodic requires to cover
the same frequencies and probably still not achieve the same gain and/or
BOTTOM LINE: A strong case can be made that StepIR is likely to be MORE
mechanically reliable than designs which use traps and other loading gizmos
combined with directly exposing metal radiators to the elements. In
addition, I suspect most log periodic advocates will eventually 'pack it in'
and switch to the StepIR. Log periodics may well end up in history
alongside crystal receivers, regenerative receivers, crystal controlled
transmitters, amplitude modulation, etc. But, the users of those old
technologies, at the end of the era in which it was dominant, were real
skeptical about what eventually killed their favorite technology. (Remember
all the bashing of SSB - duck talk - when it first came out?) So, am not
surprised there are skeptics who currently use antennas made of traps and
other loading gizmos while also exposing lots of metal to the elements and
requiring real sturdy tower.
StepIR's mechanical adjustment of element length within a fiberglass
tube certainly seems to me to be a strong contender for replacing many
current designs, especially when compared to the log periodic. That,
combined with its smaller weight & wind load, smaller footprint, lack of
metal exposed to the elements, no TRAPS etc will make it a powerful option
for all of us. (Isn't competition great?)
Thanks for the other points that have been made thus far. I really enjoyed
them and found them helpful.
73 de Jim WA6PXU@ARRL.net