[TowerTalk] Xm240 to moon - Link to W6NL_Moxon104.pdf

[marsh at ka5m.net]

Thank you Dave.

73,
Marsh KA5M


-----Original Message-----
From: Leeson <leeson at earthlink.net> 
Sent: Saturday, May 20, 2023 6:03 PM
To: marsh at ka5m.net; 'BRUCE FORD' <ks9u at aol.com>; towertalk at contesting.com
Subject: Re: [TowerTalk] Xm240 to moon - Link to W6NL_Moxon104.pdf

 From W6NL: The history of this antenna begins with my 2003 antenna with 
27-foot boom, designed for our 125 mi/h (200 km/h) winds. See 
https://www.kkn.net/dayton2004/dayton-2004-antenna-forum.html This 
antenna is still in use here. Copies were built by K5MR, K6KR, KZ1W and 
others. The K5MR antenna is now at N4BAA.

In 2007, K3LR asked me to modify the design for less wind load than we 
have here, for convenience to be built with available parts of the 
Cushcraft XM240. See http://www.kkn.net/dayton2007/w6nl_ant.pdf and 
http://www.k3lr.com/engineering/ The first try 
www.k3lr.com/engineering/moxon/W6NL_Moxon104.pdf was not quite strong 
enough for the winds there, so a modified design was made in 2010 as 
www.k3lr.com/engineering/moxon/W6NL_Mox_100.pdf In 2012, W2SC asked me 
to provide an updated design to use at 8P5A, see 
www.k3lr.com/engineering/moxon/W6NL_Mox_Tube_100.pdf For a discussion of 
modeling this type of antenna, see 
www.k3lr.com/engineering/moxon/W6NLMoxonModeling.pdf

These have been built by W1UJ and K1KP in a project of the Yankee 
Clipper Contest Club, for their own use and for W2SC/8P5A. See 
https://w1uj.net/Moxon/ Here you will find many files describing their 
work to build these antennas. See particularly K1KP's Dayton talk 
https://www.kkn.net/dayton2012/DaytonAntennaPaper05102012.pdf and
https://www.yccc.org/Scuttlebutt/2011/butt2011_10.pdf Also see 
https://w1uj.net/Moxon/K1KP/readme.html

In 2014 I was asked by WE9V to update the design to account for some 
minor errors he found in the wind calculations. Also, he wanted to make 
his antenna from 6-foot (2-meter) lengths of tubing. The antenna was 
finished in 2015, see https://www.we9v.com/antennas.htm The element 
dimensions for this antenna are in WE9V Moxon 100 mi.pdf and Visio-Moxon 
Cushcraft XM240 40M.pdf The dimensions from WE9V are here, from an email 
from me to him near the end of his project:

"So in summary, an antenna making good use of XM-240, especially the 
expensive bigger sections, has 99 mi/h survival and should have the same 
electrical performance as the other W6NL-Moxons. The elements, all with 
0.058" wall, are as follows for the reflector, which is the more 
stressed element:

1-1/2"x72"   EH and EA used as reinforcement, add new 1-1/4"x24" inside
1-3/8"x72"   42" exposed, with reinforcement inner 24"
1-1/4"x48"   45" exposed, EB
1-1/8"x48"   44" exposed, EC
1"x16"       13" exposed, half ED
7/8"x18"     14" exposed, new part
3/4"x6"      Reinforced, new, to mount cross element
1/2"x48"     39" exposed , EF (could be more or less)
3/8"x36"     13.25" exposed, half EJ, for proper tip length

For the driven element:

1-1/2"x72"   EH and EA used as reinforcement, add new 1-1/4"x18" inside
1-3/8"x72"   42" exposed, with reinforcement inner 15"
1-1/4"x48"   45" exposed, EB
1-1/8"x48"   44" exposed, EC
1"x16"       2" exposed, half ED
7/8"x18"     2" exposed, new part
3/4"x6"      Reinforced, new, to mount cross element
1/2"x48"     39" exposed , EF (could be more or less)
3/8"x36"     32.5" exposed, EG, for proper tip length

I hope this is what you were looking for. My grandkids always tell me "TMI."

There are also commercial versions of my design, such as W3JK's JK402T 
https://jkantennas.com/jk402t.html, see also 
https://ac0c.com/main/page_acc_towersantennas_40m_stack.html The JK402T 
has several clever mechanical features, such as the mounting bracket for 
the cross elements. But it is expensive, so many hams prefer to build 
from scratch. DX Engineering has been rumored to be considering offering 
a kit based on my design, but nothing concrete at the moment.

73 de Dave, W6NL/HC8L/P40Q

On 5/20/23 1:33 PM, marsh at ka5m.net wrote:
> The attachment didn't work, so here's the link:
> 
> http://www.k3lr.com/engineering/moxon/W6NL_Moxon104.pdf
> 
> Hope this helps.
> 
> Marsh KA5M
> 
> 
> 
> 
> -----Original Message-----
> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of BRUCE FORD via TowerTalk
> Sent: Saturday, May 20, 2023 2:54 PM
> To: TowerTalk at contesting.com
> Subject: [TowerTalk] Xm240 to moon
> 
> I know I am late (always) to this but downsizing and replacing the 160 ft rotating tower with a nice 3el 40 with a 70ft Tristao and a XM240. The band width is not so great and have been reading about this upgrade. I can find no actual pictures of the Moxon element fully constructed so I have to assume looking at tubing lengths each element is about 18ft in total or 9 a side from the boom. Sorry so stupid…just getting old I guess.If anyone has picture of element end constructed and mounted that would be great.
> 
> Thanks for any help
> 
> Bruce K9RO
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