I'm surely not trying to trash anything or anybody. I was just taking issue
with someone's statement, way back in a thread that started last week, that
the SteppIR was "optimized for all bands," which seems impossible with a
fixed boom length.
"If everything seems under control, you're just not going fast enough." -
> -----Original Message-----
> From: Joe Reisert [SMTP:firstname.lastname@example.org]
> Sent: Thursday, September 19, 2002 12:10 PM
> To: Zivney, Terry L.; email@example.com
> Subject: Re: [Towertalk] SteppIR Performance and misleading
> Terry and Steve (WB2WIK),
> Why are you guys trying to trash Fluid Motion and putting our false data.
> If you notice, Fluid Motion gains are published in QST. Although they are
> in dBi (the typical numbers done with computer modeling), one only had to
> subtract 2.1 for dBd. They aren't trying to pull some fancy testing or
> ground gain etc, like some companies do! The truth of the matter,
> to Mike at Fluid Motion, is that they did send the antenna out to an
> antenna range and had the gain measured. If they hadn't done this and
> didn't have the proper modeling, ARRL would not have accepted their
> advertisements with the gain included.
> As for the Fluid Motion performance claims etc., it is easy to verity on
> YO etc. using 22 Ohm feed impedance. I've done it. The chosen driven
> element resonance impedance for their design is about 22 Ohms so they use
> Sevick type unbalanced to balanced toroid to get a 50 Ohm match. 15 meters
> is near the optimum boom length (about 0.35 WL). However, the shorter boom
> does penalize 20 meters by about .5-.7 dB, a small price to get good
> performance from 10 meters through 20 meters on a 3 element Yagi.
> Furthermore, if you don't like the settings they provide (several
> frequencies for 10, 15 and 20 and one for 12 and 17 meters), you can set
> you own and go for maximum gain with poorer F/B, not a bad choice for
> not needing high F/B like us on the coasts.
> Joe, W1JR
> At 08:54 PM 9/18/2002 -0500, Zivney, Terry L. wrote:
> >Page 154, October 2002 QST:
> >"performs as predicted by YO and EZNEC within .25-.50 dB"
> >is patently unverifiable. I have no problem with the ad
> >included a chart based on computer modeling but they have
> >no way of proving that their actual physical HF antenna
> >is within .25-.50 dB of the computer models, especially
> >since they give free space gains and I am quite certain
> >the manufacturer does NOT have a free space antenna
> >Similarly, I am quite sure they have no way to confirm
> >that the actual conductor losses are .17 dB; rather the
> >model predicts losses of .17dB
> >Again, to summarize, the table is ok - but the
> >claimed accuracy puts them in the Gotham category
> >when it comes to accuracy in advertising.
> >Terry Zivney, N4TZ/9
> >Self Supporting Towers, Wireless Weather Stations, see web site:
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> Self Supporting Towers, Wireless Weather Stations, see web site:
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