Adding ground gain was a trick some manufacturers used to inflate the specs
in their ads. That led to QST banning any gain claims for decades.
I prefer the very basic dBi, then you can toss in the extra numbers if it
makes one feel better!
W2PV selected .59 wave booms. These are non resonant which helps the real
world to conform to the model as well as offering less degradation in
multiband stacking than some other designs.
My current interest in contesting is nil. I often need/prefer deep f/b nulls
when chasing a new one as well as reducing pesky line noise.
When KQ2M was operating from here one effective way of clearing a hole was
to swing one of the antennas stateside when running EU. Depending upon
angles it could have been any one of the 4 in the stack. For WPX he often
kept one pair on EU and the other on USA and constantly moved them around as
propagation dictated. Whatever it took.
I remember one CQ WW that I operated only 10M and worked WAZ in that
weekend. The only antenna that could hold a big JA run in the evening was at
25'. Switching in any other combination dropped them 10-20dB. But thats
drifting off subject.
Now I just have to finish the killer 6M array and get it up on the 180'
tower. At least it will be easier than fighting the KLM 4M-40 that used to
fly there.
Carl
KM1H
----- Original Message -----
From: "Dick Green" <wc1m@msn.com>
To: "'jeremy-ca'" <km1h@jeremy.mv.com>; <towertalk@contesting.com>
Sent: Sunday, July 01, 2007 12:38 PM
Subject: Re: [TowerTalk] SteppIR
> 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@jeremy.mv.com]
>> Sent: Friday, June 29, 2007 2:02 PM
>> To: Dick Green; towertalk@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@msn.com>
>> To: "'Bob Maser'" <bmaser@tampabay.rr.com>; "'Joe Subich, W4TV'"
>> <w4tv@subich.com>; "'Carl Smidt'" <xveoneov@primus.ca>;
>> <towertalk@contesting.com>; <SteppIR@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@tampabay.rr.com]
>> >> Sent: Friday, June 29, 2007 12:00 PM
>> >> To: Joe Subich, W4TV; 'Carl Smidt'; towertalk@contesting.com;
>> >> SteppIR@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@subich.com>
>> >> To: "'Bob Maser'" <bmaser@tampabay.rr.com>; "'Carl Smidt'"
>> >> <xveoneov@primus.ca>; <towertalk@contesting.com>;
>> >> <SteppIR@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@contesting.com
>> >> >> [mailto:towertalk-bounces@contesting.com] On Behalf Of Bob Maser
>> >> >> Sent: Friday, June 29, 2007 8:50 AM
>> >> >> To: Carl Smidt; Richard J. Fiero II W5TFW;
>> >> >> towertalk@contesting.com; SteppIR@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
>> >>
>> >
>> >
>> > _______________________________________________
>> >
>> >
>> >
>> > _______________________________________________
>> > TowerTalk mailing list
>> > TowerTalk@contesting.com
>> > http://lists.contesting.com/mailman/listinfo/towertalk
>> >
>
>
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>
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