[TowerTalk] SteppIR

Sun Jul 1 12:38:30 EDT 2007

Yeah, I think there's something wrong with the F/B in my models. I'm looking
into it.

The figures I posted included ground gain. The forward gain of 14.36 for
SteppIR and 14.29 for Force12 are about right, and match the figures
published by SteppIR and Force12. SteppIR publishes free-space gain of 9.5
dBi, which a little higher than I get when I run my models with free-space
gain (8.74 dBi.) My models are closer to the theoretical difference of 5.9
dB between free-space gain and gain over average ground. Force12's published
gain for the EF-420 at 74' over average ground is 14.5 dBi, which is very
close to my model's 14.29 dBi (96' over EZNEC's REAL/MININEC ground.)

As for F/B, SteppIR publishes 21 dBi and Force12 publishes 22 dBi. My models
are showing about 3 dB less, so there could be something wrong with them.
It's odd that I have the same error on the Force12 model, which is more
standard than the SteppIR model (the latter requires some tricks to model.)
Again, I'm looking into it.

As for F/B, it's true that it helps in certain contest situations,
especially in CQWW and ARRL DX. There are other contests, like CQ WPX, where
a little less F/B actually helps. In the big DX contests, these days the
problem is less about interference from loud adjacent US stations than from
loud adjacent EU stations. F/B doesn't do anything to help in that
situation. In fact, a little less F/B can help keep your frequency clear of
close US stations. That's the effect I get from my 40-2CD, which has
terrible F/B. But of course there are times when I want deep F/B. It all
depends on the situation.

73, Dick WC1M

> -----Original Message-----
> From: jeremy-ca [mailto:km1h at jeremy.mv.com]
> Sent: Friday, June 29, 2007 2:02 PM
> To: Dick Green; towertalk at contesting.com
> Subject: Re: [TowerTalk] SteppIR
> 
> Something is VERY wrong with those gain figures Dick. Are you adding
> ground
> gain?
> 
> And if the F/B is real Im not at all impressed with either. I could
> demonstrate at least 20dB F/B and 30-35 dB over 200 kHz with my 20M 4el
> PV.
> Those tests were run many times when N6BV lived a few miles away in
> Windham.
> We also ran similar tests on my 15 & 10M versions. Id much prefer deep
> F/B
> nulls in DX pileups and not worry about perfect VSWR or losing a few
> tenths
> of a dB in gain.
> 
> Carl
> KM1H
> 
> 
> ----- Original Message -----
> From: "Dick Green" <wc1m at msn.com>
> To: "'Bob Maser'" <bmaser at tampabay.rr.com>; "'Joe Subich, W4TV'"
> <w4tv at subich.com>; "'Carl Smidt'" <xveoneov at primus.ca>;
> <towertalk at contesting.com>; <SteppIR at yahoogroups.com>
> Sent: Friday, June 29, 2007 1:34 PM
> Subject: Re: [TowerTalk] SteppIR
> 
> 
> >I don't want to get in the middle of this, but I just ran EZNEC models
> > comparing the 4-el SteppIR and Force-12 EF-420 on 20m at 96'. The
> SteppIR
> > boom is 32'; the EF-420 boom is 30' (and presumably optimized.)
> Results:
> >
> > 4-el SteppIR Force-12 EF420
> >
> > Elevation at max gain: 10 degrees 10 degrees
> > Forward gain: 14.36 dBi 14.29 dBi
> > Front/Back: 18.12 dBi 17.35 dBi
> > Front/Side: 18.12 dBi 17.35 dBi
> > Beamwidth: 60 degrees 60 degrees
> >
> > It would be hard to tell the difference between these two antennas. I
> have
> > both installed, but the EF-420 is only at 72' on a tower that doesn't
> have
> > as good terrain as the tower on which the SteppIR is mounted. The
> SteppIR
> > consistently outperforms the EF-420, usually by as much as 5 dB. I
> > attribute
> > that entirely to the difference in height and terrain.
> >
> > I have not done models for 15m and 10m because I don't have data for
> any
> > 4-el antennas for those bands. But I have compared the 4-el SteppIR
> with a
> > Force-12 515 (5-el on 15m, 24' boom) and a Force-12 616 (6-el on 10m,
> 24'
> > boom.) The gain figures are nearly identical, but the F/B on the
> SteppIRs
> > is
> > lower, especially on 10m (a well-known characteristic of the SteppIR
> > design,
> > resulting from inability to place the elements optimally on all three
> > bands.) The gain being comparable suggests that optimized 4-el
> monobanders
> > for 15m and 10m would outperform the SteppIR. But I don't know by how
> > much.
> >
> > 73, Dick WC1M
> >
> >> -----Original Message-----
> >> From: Bob Maser [mailto:bmaser at tampabay.rr.com]
> >> Sent: Friday, June 29, 2007 12:00 PM
> >> To: Joe Subich, W4TV; 'Carl Smidt'; towertalk at contesting.com;
> >> SteppIR at yahoogroups.com
> >> Subject: Re: [TowerTalk] SteppIR
> >>
> >> Joe, have you been smoking weed again?  It's affecting your brain.
> >> Your
> >> logic makes no sense at all. A 4 element on a 34 foot boom at the
> same
> >> height and optimized with YO or some other optimization program will
> >> outperform the SteppIR if both antennas are reasonably close by.
> You
> >> sound
> >> like someone trying to justify spending all that money.  Better you
> >> should
> >> light some candles and pray that the element drive motors stand up.
> >>
> >> Bob W6TR
> >> ----- Original Message -----
> >> From: "Joe Subich, W4TV" <w4tv at subich.com>
> >> To: "'Bob Maser'" <bmaser at tampabay.rr.com>; "'Carl Smidt'"
> >> <xveoneov at primus.ca>; <towertalk at contesting.com>;
> >> <SteppIR at yahoogroups.com>
> >> Sent: Friday, June 29, 2007 10:30 AM
> >> Subject: RE: [TowerTalk] SteppIR
> >>
> >>
> >> >
> >> > Bob,
> >> >
> >> >> For any specific band most monoband antennas will stomp a
> SteppIR,
> >> >> assuming that the boom length is the same or longer than the
> >> SteppIR.
> >> >
> >> > That's complete nonsense unless you are comparing something like a
> >> > 60 foot boom monobander.  YO shows a 1 dB advantage for the 4
> element
> >> > over the 205CA because the 205CA gives up gain to maintain usable
> SWR
> >> > across the entire band.  The N6BV optimized design (BV205) is
> about
> >> .5 dB
> >> > below the SteppIR.
> >> >
> >> > It takes a much larger monobander (6 el 60 foot on 20, 6 el 48
> foot
> >> > on 15 and 7 el 48 foot on 10) to achieve at least 1 dB more gain
> than
> >> > the SteppIR.  Sure, one could put up a set of WA3FET (K3LR) OWA
> >> antennas
> >> > for each band but not on one tower.
> >> >
> >> > 73,
> >> >
> >> >   ... Joe, W4TV
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >> -----Original Message-----
> >> >> From: towertalk-bounces at contesting.com
> >> >> [mailto:towertalk-bounces at contesting.com] On Behalf Of Bob Maser
> >> >> Sent: Friday, June 29, 2007 8:50 AM
> >> >> To: Carl Smidt; Richard J. Fiero II W5TFW;
> >> >> towertalk at contesting.com; SteppIR at yahoogroups.com
> >> >> Subject: Re: [TowerTalk] SteppIR
> >> >>
> >> >>
> >> >> Carl, your bragging doesn't make any sense at all.  For any
> >> >> specific band
> >> >> most monoband antennas will stomp a SteppIR, assuming that
> >> >> the boom length
> >> >> is the same or longer than the SteppIR.  For band hopping
> >> >> convenience, I
> >> >> would agree with you  that the SteppIR antenna is better than
> most
> >> >> tribanders.  All of this bickering back and forth has become
> >> >> tedious at
> >> >> best.
> >> >>
> >> >> Bob  W6TR
> >>
> >
> >
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