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Re: [TowerTalk] SteppIR

To: <john@kk9a.com>, <TOWERTALK@contesting.com>
Subject: Re: [TowerTalk] SteppIR
From: "Joe Subich, W4TV" <w4tv@subich.com>
Date: Fri, 29 Jun 2007 20:15:05 -0400
List-post: <mailto:towertalk@contesting.com>
> It would be interesting to compare the 4el SteppIR and a 5 
> element 10m beam with the same boom length.  I think you 
> would see a bigger difference on 10m, especially with  F/B.

Yes, you will see a significant difference in F/R ... the five 
element, 32 foot boom will provide 20 to 25 dB across 28.00 to 
28.80.  However the gain difference will be less than .3 dB. 

73, 

   ... Joe, W4TV 
  


> -----Original Message-----
> From: towertalk-bounces@contesting.com 
> [mailto:towertalk-bounces@contesting.com] On Behalf Of john@kk9a.com
> Sent: Friday, June 29, 2007 4:43 PM
> To: TOWERTALK@contesting.com
> Cc: wc1m@msn.com
> Subject: Re: [TowerTalk] SteppIR
> 
> 
> It would be interesting to compare the 4el SteppIR and a 5 
> element 10m beam 
> with the same boom length.  I think you would see a bigger 
> difference on 
> 10m, especially with  F/B.
> 
> John KK9A
> 
> 
> To: "'Bob Maser'" <bmaser@tampabay.rr.com>,"'Joe Subich, W4TV'" 
> <w4tv@subich.com>,"'Carl Smidt'" <xveoneov@primus.ca>, 
> <towertalk@contesting.com>,<SteppIR@yahoogroups.com>
> Subject: Re: [TowerTalk] SteppIR
> From: "Dick Green" <wc1m@msn.com>
> Date: Fri, 29 Jun 2007 13:34:17 -0400
> List-post: <mailto:towertalk@contesting.com>
> 
> 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 
> 
> _______________________________________________
> 
> 
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