[Towertalk] Need Antenna Advice!

[Steve Katz]

> There is an optional fixed 6 meter director available for the SteppIR
> that is suppose to greatly improves the F/B ratio:
> 
> http://www.steppir.com/
> 
> Look under the "products" tab for the  "6 meter passive element kit".
> The list price is $79.95, but you could probably make your own easily
> enough (it looks like nothing more than a piece of tubing and a U-bolt).
> Of course assuming this is a director, you probably lose the ability to
> do instant 180 deg switching on 6 meters with this installed.
> 
> 73 de Mike, W4EF....
> 
	Roger that, Mike.  But modeling indicates less than 15 dB F/B as
best achievable on 10m, and about 12 dB on 12m; don't think the extra 6m
element will help those, although possibly it does.  Anybody have any real
data?  -WB2WIK/6  



> .................................................
> 
> ----- Original Message -----
> From: "Steve Katz" <stevek@jmr.com>
> To: "'Mark Beckwith'" <mark@concertart.com>; <towertalk@contesting.com>
> Sent: Friday, September 13, 2002 3:39 PM
> Subject: RE: [Towertalk] Need Antenna Advice!
> 
> 
> >
> >
> >
> > > >The StepIR is an optimized 3L beam AT
> > > >ALL FREQUENCIES.
> > >
> > > That depends on how you define the word "optimized," eh?  I don't call
> > > fixed
> > > element locations on the boom optimized on more than one band.
> > >
> > > Mark, N5OT
> > >
> > [Steve Katz]  Mark, I have to agree.  Unless this antenna defies all
> > the modeling programs, using a 16' boom and fixed element locations
> provided
> > in the SteppIR manual, and modeling using NEC, if I adjust the element
> > lengths in 1" increments indefinitely, to try every combination of
> element
> > lengths there is from 10" to 432" per element using (N+1...) algorithms,
> I
> > cannot come up with any combination that provides more than about 6dB
> F/B
> on
> > six meters, for example.  The original claims for F/B on "all bands" is
> > "20-50 dB, depending on frequency" for the 3L model, but I can't use any
> > modeling integers that indicate that, at any element lengths or any
> height
> > above ground.  If the inventor/manufacturer can provide us with some new
> > data on this matter, I'd love to receive it!   Better still, I'd like to
> > know what the exact element lengths are to provide max F/B on each band,
> > based on the 16' boom length and fixed element spacing.  Then I can
> scale
> it
> > 1:10 and stick the model in our RF anechoic chamber here at the lab, and
> > take actual (empirical) data.  I'll be happy to provide the test report
> in
> > this forum, if I can get the data to make the model. -WB2WIK/6
> >
> >
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>