[TowerTalk] 40M Steppir? Long answer coming
n6ta at arrl.net
Thu Mar 4 14:56:18 EST 2004
I copy below my request for info on new yagis and this is what I got back.
Read from the bottom up, if you want it in time order:
Al, Sorry I forgot wind loads. As follows; The approximate wind load for
the 2 element is 7.7 sq feet, the 3 element ( two elements moxon type) 9.5
sq feet, the 4 element (two elements moxon type) 13.5 sq feet, the full
size 4 element (one element 36' three 70') 22 sq feet.
Regards Mike K7IR
Sorry my e-mail wasn't very clear I'm always rushing it when I type because
I'm a hunt and pecker! First it may clear a lot up if I explain the
element operation. Any element we make will goes from zero length to its
full design length. This means the 50' Moxon element works from 6.8mHz -
54mHz (higher actually because it goes to almost zero length - our balun
only makes 70mHz or so, thats the limit and the spacing is wayyy too far
between elements above 6M). This means the 50' elements work perfectly
well on every frequency (yes even between hambands) from 6.8 mHz - 54
mHz. Moxon just means we have bent the full length element in at the end
to give it an L shape the copper tape goes out a full 70' by turning the
corner. Look in the Ham literature to see what a Moxon is - it looks like
a rectangle because you turn the ends of each of the 2 elements of a 2
element beam in towards each other and mechanically connect them for
strength. The advantage is a shortened antenna that outperforms a fullsize
classic Yagi!! This all of these antennas except the 2 el 40M - 15M will
work quite well on 6M just as they are. However by adding 1 or 2 passive
elements (depending on whether its a 3 or 4 el model) it will make an
elephant gun on 6M! The 2 el 40M - 15M will actually keep working at
higher frequencies with gain but diminishing F/R and a rising SWR. The
spacing gets so wide that the impedance rises up to approaching 50 ohms and
our 25 ohm to 50 balun shows a 2:1 SWR, but you still have gain!
The truss goes 32" up from the mast plate. I hope this helps and
sorry for the confusion.
Regards Mike K7IR
At 11:27 AM 2/25/04, you wrote:
>Thank you kindly for the information on your new efforts. Since I am a
>little 'slow' please allow me to summarize what I understood. A couple of
>clarifications would be appreciated to allow me to completely focus and
>the choice. I am referring to the ham bands and understand that they will
>work between as well. 50' elements 6.8MHz to 21.45MHz(or ??) and 36' from
>13.8MHz to 29MHz or so.
>Elements: 2 each 50' long
>Elements per band: 2 on 40-15m, 0 on 12-10m
>Elements: 2 each 50' for 40-15m plus 1 each 36' for 20-10m
>Elements per band: 2 on 40 and 30m, 3 on 20-15m, 1 on 12-10m
>Elements: 2 each 50' for 40-15m plus 2 each 36' for 20-10m
>Elements per band: 2 on 40 and 30m, 4 on 20-15m, 2 on 12-10m
>Elements: 2 each ~67' for 40m plus 1 each 36' for 20-10m
>Elements active per band: 3 on 40m thru 15m or 10m?? and 1 on 20-10m.
>Questions that come to mind:
>1. When adding the optional 36' elements, I assume the 50' elements are
>still covering 15m. You mention "will give 2 el on 6.8 mHz -13.8 MHz...".
>Seems like they should still be active to get the total number on 15m of 3
>2. You mention "either 3 or 4 elements the rest." when referring to adding
>the 1 or 2 additional 36' elements. Do 12 and 10 meters really have 3/4
>total or 1/2 elements? If adding 1/2 elements to the 50'ers, does the 50'
>now work above 15m?
>3. I assume one limitation to range involves how much BeCu tape you want to
>roll up in the center.
>4. Any rough estimate of wind load sq ft for Design 1 with the two added
>elements and for Design 2? This is important relative to my tower and
>I have 50' 45G (guyed at 30' and 50') and a 20' 4130 2" mast.
>5. To work with the wind load, I need to know how much of my mast I can use
>so I need to know how far above the boom the truss is fixed to the mast.
>This also applies to the current 4 element. I cannot find anything on your
>site that tells me where the truss is attached above the boom.
>6. You make no specific mention of 6m so I assume it is a casualty for
>getting the lower frequency coverage.
>Anyway, what is of primary interest to me is getting traditional 4 element
>SteppIR performance on 20-10m with something on 40-30m. Answers to the
>above first two questions will clarify and help me decide if I want to
>Sorry for the minutia but I guess it is my nature. Your comments on the
>are interesting. I will look for some info on how high the antennas are
>mounted on the range.
>Again, thank you very much, Mike.
>From: Mike Mertel [mailto:mikem at steppir.com]
>Sent: Tuesday, February 24, 2004 3:23 PM
>To: Al, N6TA
>Subject: Re: 40M offering status request
>Thanks for you interest in our antennas. We are working on 40M and up
>antennas as we speak. We will have a 2 element moxon configuration with a
>10 foot boom and 50 foot wingspan that will out perform a fullsized regular
>2 element. This antenna will work very well up to the 15M band,
>continuous coverage. On 40M it will have 7.1 dBi freespace and 23 dB F/R
>decreasing as frequency increases to more typical 2 element specs on
>15M. We will offer this antenna with one or two additional 36 foot
>elements that will give 2 el on 6.8 mHz -13.8 mHz and either 3 or 4
>elements the rest. The booms will be 17' and 32' respectively. The
>performance will be almost identical to our 3 el and 4 el on 20M and up,
>which by the way I guarantee the 4 el will significantly outperform a C31XR
>(I know because I own 3 C31XR's and have range tested them against our 4
>el). We will also offer a 32 boom with 3 fullsize 40M elements and one 36
>foot element that will give you 3 el on 6.8 mHz - 13.8 mHz and 4 on the
>rest. The bad news is we won't have them until late summer, hope you can
>wait that long.
>Regards Mike Mertel K7IR
>At 06:29 PM 2/23/04, you wrote:
> >You are likely to get a lot of similar requests (if you haven't already!)
> >about your new design. Here goes mine:
> >I am at a decision point in selection of the new yagis. I have spend a
> >amount of time weighing my wants vs. needs, current offerings, and the
> >chatter about performance of the current antennas out there. I am
> >considering these options:
> >1. 4 element SteppIR and an additional yagi for 30 and 40m. It would be
> >elements on 40, probably.
> >2. Force 12 C31XR and their WARC 7 and nothing for 40m.
> >3. A new SteppIR that includes 40 and 30m.
> >I know about the first two options but not about the new design of yours.
> >would seriously considering waiting for your new offering if I knew a
> >of things about it.
> >1. Is performance of 20-10m likely to be similar to the 4 element
> >i.e. same number of elements on 20-10m?
> >2. Would it be 2 or 3 elements on 40/30m?
> >FYI. I do not care about 6m or 28.5-29MHz. I am not a contester but avid
> >DXer. I want gain where I point and am less concerned about other
> >specs like f/b ratio.
> >If you are not in a position to respond with anything that is reasonable
> >solid, I certainly understand. However, if you can say something at all,
> >would certainly be appreciated. My current inclination is for the Force
> >combination but may delay based on what I can learn from you.
> >Thanks in advance.
> >Regards y 73,
> >Al Toothaker
> >P.S. Maybe you need to write the party line down and send it to all who
> >this question. Could be less time and effort for you! Or post it on the
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com]On Behalf Of Doug Faunt N6TQS
Sent: Thursday, March 04, 2004 11:19
To: gclute at comcast.net
Cc: wtrone at comcast.net; towertalk at contesting.com
Subject: Re: [TowerTalk] 40M Steppir?
Any rumor level information that it might cover 30M as well?
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
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