26GB82
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Wickes alloy Moxon.
Hopefully I've got a picture of my home brew Moxon above.
As I don't have a local tame supplier of aluminium tube and I didn't want to fly a wire and bamboo antenna long term due to the wobbly looks and durability of materials I bought some 18 mm aluminium angle from Wickes DIY store in nearby Yeovil.
I used the MoxGen software available online but entered 15 mm diameter wire (obviously no allowance for angle)as the parameter for calculating the antenna dimensions which shortened most dimensions due to surface area when compared to a more normal 1.5 mm csa.
The antenna performs pretty much the same as a normal two element yagi so not a massive amount of forward gain and indeed on days when Europe is coming through the vertical will often produce a stronger signal with better high angle reception of the relatively local stations in say Spain and France.However on more distant stuff the Moxon will produce the goods and more importantly as with all beams can focus its attention on the interesting stuff and to some extent turn its back on undesired signals reducing them by up to 6 S points at times even if you're compromising and not beaming directly to the desired station but anxious to lose some local QRN/QRM.
Additional pluses with the Moxon when compared to a standard two element Yagi are its reduced visual footprint at only 3.9 M or just under 13 feet wide with a boom under 1.5 M (5 feet)
and the fact that there's no messing around with matching the coax to the centre feed point of the driven element.Impedance matching is provided by the insulated spacing between the element ends where they are folded towards each other the only precaution neccesary at the feed point is some sort of air cored big ugly balun to cancel the coax outer radiating.....I used a non scientific five 6" diameter turns of the feed coax taped to the boom.
Note the elements are full size and all supporting parts ie. the boom and the element supports have to be non conducting (wood and tyraps in my case)but by folding the driven element and reflector at the prescribed places and ensuring that the gap between the ends is maintained(plastic angle pop rivetted in place) the antenna is similar in size to a full wave wire loop laid flat but sturdier and with a larger capture/surface area.
I won't pretend that the Moxon performs as well as the Quad antenna that it replaced but at least with this antenna the neighbours aren't up in arms unlike the deputation that came bustling round from next door three days after the Quad first flew.
Lovely Quadliness! I did move the mast too on the Moxon build as apparently wherever they looked from their back garden all they could see was my antenna....yes I know they're out of order but as pensioners and in his case a semi retired vicar I figured I wasn't going to win too much sympathy toughing it out and might end up downstairs rather than upstairs come clocking off time!
That's the mast which is 3" aluminium box section with a 2.5" tube inside,sadly the two main parts started out at 6 M long but due to them hanging over the ends of the car considerably I had to chop them down to 5 M each before carting them the 150 miles from the ASC Metals in Northampton to home here in Dorset.The shameless plug for the alloy stockist and the fact that I made the journey was a combination of family visit and family member working there allowing me to wander through the warehouse mixing and matching....a lighter 2" box section plus suitable inner tube would make a great portable setup mounted alongside or on the car/van although again the 6 M length comedy value might be a non starter!
Cheers all,Dave 26 GB 82.
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2/Feb/2009, 1:00 pm
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topbuzzuk
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Re: Wickes alloy Moxon.
excellent post there Dave, although i have those pics already i regularly dribble over the mast, which i hope to copy at my new address as it looks lightweight and simple/ish to construct. Be nice to have some skip to give the moxon a really good try out
--- 
26~FoxtrotBravo~118 |
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2/Feb/2009, 1:17 pm
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26GB82
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Re: Wickes alloy Moxon.
Hi Paddy,the mast was fun to make with plenty of skinned knuckles and nearly filling my pants straining to get the mast+antenna+rotator upright and bolted to the wall brackets.
I worked several 47 stations at 5 and 9 plus two weeks ago today which was my previous Monday off,checking my anorak notepad they were actually:- 161 AT 142 Marin,161 SD 137 Jack,47 DX 117 John,47 DX 054 Leif,47 AT 124 Palle all over a 1 1/2 hour period from 10:40 19th Jan last month.
The skip popped up from an otherwise dead band starting by giving Germany on mid block FM around 27.355 (a good place to listen for openings due to high population of band)and swept up through Poland to close on Denmark. Don't get me wrong mate all stations could have been worked on the vertical too possibly a piece of damp string at its height as it was quite localised and intense.
In an ideal world most stations would listen in all directions with the omni directional vertical antenna then go in for the kill by directing all their energy towards the target station,the Moxon is comparatively small but satisfies that criteria.
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2/Feb/2009, 1:40 pm
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yamanx1
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Re: Wickes alloy Moxon.
Good write up there Dave, I have the same antenna for 6m, although its not used very much atm, in fact I have only ever made one single contact on 6m in over a year!!
The quad looks precarius, but I bet it works well 
I like the mast, I have a flagpole style mast as well, it's not telescopic like yours and I use a winch from a tree to erect it. Bends and sways around all over until its vertical
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2/Feb/2009, 3:25 pm
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Hot Fusion
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Re: Wickes alloy Moxon.
Very nice!
I'll have to educate myself on this Moxon lark - it's a configuration I'm not familiar with.
---
Andy - 26FB107
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2/Feb/2009, 6:40 pm
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TheRealKeyboard
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Re: Wickes alloy Moxon.
Excellent post - I very much enjoyed that. Thanks! 
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4/Feb/2009, 2:30 pm
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Kaosss
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Re: Wickes alloy Moxon.
Nice set up you have there, like the mast-must pay a visit to Wickes and the Alli place near me see what they have. Agree with you on keeping the neibours happy, allways a good idea-if you can, some just dont want to know, hopefully they are the minority as I have good neibours here, at least on one side, the others can be a bit funny!
---
Al -163FB777 - N.Wales, UK
Kenwood TS-480SAT, MC-60A mic, 827-Base + 3 elli beam
K40 when mobile
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4/Feb/2009, 3:08 pm
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26GB82
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Re: Wickes alloy Moxon.
I think the general consensus would be to keep the right side of neighbours even letting them as in my case bully me into taking down the quad,in that case there was dialogue and a compromise reached leading to another directional antenna which is far better than blundering on to the bitter end and leaving an unknown depth of hostility and possible enforcement orders to remove all antennas.
Unless you have the luxury of living on your own mountain there's always going to be a battle between a hobby community like ours where varying amounts of RF power are hurled into the air from unfeasibly large antennas and dare I say normal people!
Enough of that anyway as that battle will run and run if as is normal we all keep adding/changing radios and antennas in the pursuit of DX and bringing new headaches to the table.
The 18mm aluminium angle at your local Wickes is £4 something per 2.4 M length and they do a slightly larger possibly 25 mm angle if you want a slightly increased surface area, although being the same gauge there isn't a great deal of gain in mechanical strength, so no 45 M vertical using just single pieces end to end.
On my Moxon I've used aluminium pop rivets on the corners to maintain electrical conductivity and in the case of the driven element which is a conventional dipole with a small gap at the centre the coax has been split with the shield going to one side and centre conductor to the other and all buried in clear silicon, both connections using 6mm crimp lugs and small screws to fix into the alloy, the element halves being held to the wooden boom end with several sturdy nylon tyraps.
I didn't say but the paddle looking efforts at the ends of the boom that support the aluminium elements are made from 18mm plywood glued into slots cut into the boom ends and then sealed with paint.If like myself you can't cut straight even if your life depended on it you might want to cut the slots slightly over the 18 mm required(I found this dead easy!) and then set the paddle parts in place with body filler which at least gives you 5 minutes to get the elements lying perfectly inline with each other before the stuff sets.....the boom is wood and there's no loosening clamps to pull the elements around the boom options here.
I would say the antenna weighs no more than a normal 1/2" tube Yagi and is only marginally more visible at 18 mm thick looking head on.....the width though at just under 13 feet wide is a definite plus over a conventional 18 foot and means that to the untrained eye it could easily be your new Freeview antenna....right! or should an irate neighbour dare to get a more informed second opinion might confuse as to what band it's actually working, buying you time to flee the country.
Cheers all and to anyone who heard me calling CQ mobile from Dorchester today (thank you Simon FB204) I've just remembered why I wanted a decent home base setup....did I mention snow,slush,cold and no DX?
Dave GB82.
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4/Feb/2009, 5:28 pm
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26fb99
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Re: Wickes alloy Moxon.
sweet as mate.how come the "normals" cant see real beauty?bet your neighbour thinks his freshly waxed mondeo looks the bomb.ha ha.
---
yaesu FT857d,rmkl500,wilson5000,a99 (thats a real satchel of cack)/2element pubical quad(the BBq).split charger aux battery system.170a truck battery,mfj 941 versatune2
100percent mobile station
laters peeps 73s
Brent 26 Fox Bravo 99
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12/Mar/2009, 7:51 pm
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