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Re: [TowerTalk] C31XR versus SteppIR

To: <>, <>,"'Jim Lux'" <>
Subject: Re: [TowerTalk] C31XR versus SteppIR
From: "Mike Fatchett" <>
Date: Sun, 13 May 2007 16:52:14 -0600
List-post: <>
We are not talking about monobanders built on a specific sized boom.  We are
talking about multiband antennas.  Which the C31 and SteppIR are.

The reason the 10m F/B is much lower is because the driven and the reflector
are so far apart, however you can make up much of the gain loss because you
can vary the lengths of the elements.  This is supported by a number of
antenna experts which I am not.


-----Original Message-----
[] On Behalf Of
Sent: Sunday, May 13, 2007 4:08 PM
To:; Jim Lux
Subject: Re: [TowerTalk] C31XR versus SteppIR

F/B,Gain and SWR are easily measurable.  Obviously, since F/B and Gain don't
both occur with the same element lengths and spacing, there is always a
compromise, however there is an even bigger compromise when trying to use 
the same element spacing over multiple bands.   The most noticeable effect 
will be reduced F/B as the reflector is electrically further away from the
driven element as you go higher in frequency.  Gain is less effected and
apparently the 22 ohm impedance is maintained by the element length
settings.  The SteppIR is an excellent multiband antenna, however I am sure
a properly designed monobander with the same boom length that would have
better F/B and Gain on at least some of the bands that this antenna covers.

----- Original Message -----
From: "Jim Lux" <>
To: <>; <>
Cc: <>
Sent: Sunday, May 13, 2007 1:49 PM
Subject: Re: [TowerTalk] C31XR versus SteppIR

At 10:38 AM 5/13/2007, wrote:

>Joe responded (actually shouted) this statement after I stated the 
>last Friday night when comparing the subject antennas:  "The SteppIR, has 
>element interaction problems because the element lengths are adjustable,
>however the spacing is not adjustable and not optimum",   Since no limits
>were defined, I understood his comment to mean that within the frequency
>range of the SteppIR, the element spacing is irreverent.  If this is
>incorrect, then Joe, W4TV, is actually agreeing with me, that the element
>spacing of the SteppIR is not optimum on all bands.
>John KK9A

What's optimum?
Is the deviation from whatever definition of "optimum" is chosen
actually a significant (or even measureable) difference?


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