CORRECTION: My spacings are for 80m, not 40m,
but the process is the same ... start with
33' x 33' for 40m and away you go.
73/bc/NU
-----Original Message-----
>From: Billy Cox <aa4nu@ix.netcom.com>
>Sent: Feb 18, 2009 1:24 PM
>To: antennaware@contesting.com
>Subject: Re: [Antennaware] Antennaware Digest
>
>Paul, lets talk about the modeling first, and then
>when the focus in more on the hardware side, that
>would be a good time to transfer the discussion to
>another forum perhaps.
>
>Back to the modeling now ... reflect on what others
>have shared with you as to their experiences ...
>
>Here's mine ... I had a 4x 80m array around my 80'
>tower with the "tie off point" for the full size
>wire elements being at 70', just below my 40m yagi
>which was on a TIC Ring Rotor at the time.
>
>Rather than having the 4 vertical bases spaced out
>at about 65' for the typical 4 x setup, I ended up
>using mine at 105' ... why you ask? Good question!
>
>When you "lean the elements tops in" using ground
>mounted or elevated feedpoints, the average spacing
>between the elements is decreased.
>
>So instead of having 4 elements, spaced at 0.25, we
>end up with <depending on the slope> 4 elements at
>a spacing of less than 0.25, and more like 0.125w,
>which then causes challenges as to the proper way
>to phase and match the array.
>
><And I believe this is why we have mixed results
>reported with some of the K8UR type setups ...>
>
>Time spent with EZNEC confirmed the need to move
>the bases out ... so I offer that as a suggestion
>to try there with your situation.
>
>I would build up the 4x model, elements 100% vertical,
>and the 66' x 66' spacing noting the gain/F-B/SWR/etc.
>
>Next add in the 68' support and then tilt the verticals
>toward that ... note the changes in gain/F-B/SWR/etc.
>
>Now, moving all the bases outward by equal amounts, see
>what you can do to restore the gain/F-B/SWR/etc back to
>the values you noted in the typical 4x vertical setup.
>
>That help?
>
>73 de Billy, AA4NU
>
>-----Original Message-----
>>From: kg7hf@comcast.net
>>I must be subscribed to the wrong list. I didn't know this was only for
>>antenna models, what a surprise, but then again, I've only been subscribed
>>for about 2 years now, and seen maybe 10 messages go by the entire time.
>>
>>If it's for modeling, why not make a model then talk about it?
>>
>>How about this to get it started (and I am not so good of a model maker).
>>Basically, a 40m 4sq, sitting on the ground but using the ~70ft mast to hold
>>it, they slope a littel inward. I'm sure it could be tweaked to make it
>>much better. I can send the entire model if desired.
>>
>>Paul, kg7hf
>>
>> EZNEC Demo ver. 5.0
>>
>>Offset Fed Yagi -Uda for QEX 2/18/2009 12:56:36 PM
>>
>> --------------- WIRES ---------------
>>
>>No. End 1 Coord. (ft) End 2 Coord. (ft) Dia
>>(in) Segs Insulation
>> Conn. X Y Z Conn. X Y Z
>> Diel C Thk(in)
>>1 GND 0, 0, 0 0, 0, 70
>>#14 1 1 0
>>2 GND 15, 0, 0 7.7, 0, 33
>>#14 5 1 0
>>3 GND -15, 0, 0 -7.7, 0, 33
>>#14 5 1 0
>>4 GND 0, 15, 0 0, 7.7, 33
>>#14 5 1 0
>>5 GND 0, -15, 0 0, -7.7, 33
>>#14 4 1 0
>>
>>
>>
>>
>>Sources:
>>
>>Wire # % from E1 Phase
>>
>>2 0 0
>>
>>3 0 -90
>>
>>4 0 -90
>>
>>5 0 180
>
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