Other SOTA sites: SOTAwatch | SOTA Home | Database | Video | Photos | Shop | Mapping | FAQs | Facebook | Contact SOTA

Home brew 2m Moxon (fairly lightweight)

Here is a rough guide to my home brew 2m Moxon (According to some old kitchen scales it weighed in at around 160g, my luggage ‘scales’ said .2kg, but it only shows up .1kg units :slight_smile: )

I built it to take to ZL and VK, so the dimensions were for frequencies a little higher than the UK, although it seems to work fine here! It was made to be fairly easily changed from vertical to horizontal. (Although I do have to pull the mast down to do so)

To build it I needed:
A small plastic chopping board (From a pound shop) (For centre)
4 x 36cm lengths of 7mm plastic tube (For spreaders)
4 x 6cm lengths of 10mm plastic tube (to attach spreaders to the centre)
2 x15mm Plastic Pipe Clip - Saddle Band (To facilitate vertical mounting)
8 x tie wraps (To attach the 10mm tube and pipe clips to the centre)
1 x BNC bulkhead connector (female/female)
1 x BNC plug (suitable for RG174 coax)
1 x 4 way choc block
4 x short pieces of heat shrink tubing (to ensure a snug fit between the 6mm and 10mm tubes)
a short piece of RG174 coax
some wire (for the antenna!)
2 x short pieces of shock cord (to join the elements)
1 x CD (as a template for the centre!)

The CD was used as a template for marking out the circular centre for the antenna, which was then cut out with a jigsaw, and tidied up with a file. The centre hole was drilled out and tidied with a file as well (this fitted well half way down one of the sections of my travel pole, but seems to rest on the top of one of the sections of my ‘normal’ 8m pole, it could do with being enlarged slightly so that it a snug fit on a section rather than balancing on the top of one…)

Using one of the on-line Moxon calculators, the dimensions were calculated, the difficult part was trying to remember all about sines and cosines :stuck_out_tongue: and the centre lines drawn for the 4 x 6cm 10mm tubes to be attached for the spreaders. followed my lines at 5mm either side.

4 holes were drilled for each 10mm tube, 2 at 2cm from the centre and 2 at 5.5cm from the centre.

A hole was drilled through each of the 6cm long 10mm tubes, 1cm from the end, large enough to be able to fit a tie wrap through. This serves 2 purposes… To attach the 10mm tube to the centre, and to act as a ‘stop’ for the spreaders when they are inserted.
The 4 x 10mm tubes were then tie wrapped to the centre. the tie wraps on the outside were also passed through the screw holes for the pipe clips, fastening those to the centre too.
Note: the tie wraps in the centre have the ‘lock’ part away from the centre line so that they don’t foul the pole when used in the vertical position

note the tie wraps through the middle of the tubes nearest the centre

The BNC bulkhead connector can now be added too…

Spreader with notch in one end and heat shrink on the other

The 4 spreaders each had a notch cut at one end to enable the wire to be held in place.
on the opposite end to the notch, I added 4cm of heat shrink tubing to prevent the thinner tube falling out of the wider one when putting the wire on… (Truth be told, I actually squashed the end of the 7mm tube slightly to make it tighter (don’t tell anyone :wink: ))

The slightly squashed (don’t tell anyone…) and heat shrink covered spreaders insitu

Once that was done, it was a case of cutting (and folding back the excess) of the antenna wires, and joining the ends with short pieces of shock cord, joining the short length of RG174 and the driven element in the chock block, and threading the wires through the slots on the end of the spreaders. I actually used quite heavy stranded wire so that I could bend it to 90 degrees at the corners, so at least it looked nice :slight_smile:

the completed antenna

It takes a couple of minutes (at most), to build on site, I’ve used it with a short length of RG174 to the rig with the travel pole, not ideal, but weight was paramount for travel.

Vertical polarisation on a travel pole and short RG174 cable - Mt Ainslie

Also used it with a longer run of RG58, wound around the 8m pole, very close to the top!

With RG58 high on the 8m pole - Callow Hill

I did try it yesterday on Brown Clee Hill, when it was very windy… I had to drop the pole down one section otherwise it did sway around quite a bit.

All in all, I’m quite pleased with it!
No doubt it could be improved, made lighter by cutting bits out of the centre and maybe dropping the BNC bulkhead, but for less than 200G I’m not bothering!

Don
m0hcu

16 Likes

Like it :sunglasses: well smart

Broken down ready to bag up

Here’s photos of my 6m Moxon Portable .

Believe its about 500g very simple to make drill hole in board so its slides down pole and rests above the support triangle. But picture does not show latest modification of removing the metal M6 40mm bolts and wing nuts for plastic ones. thus reducing the metal work in center of the beam and lightening the load by a few grams.

Must get around to setting up and see how its tuned in as not used it yet.

Don’t you just love a good build for Portable

Karl


1 Like

Nice antenna Karl.

I put the 10mm tubes in the centre and made the spreaders ‘pluggable’ so that, at some point in the future, I could possibly use it as the basis of a 4m antenna as well. A 6m one may be a little too large for the 7mm plastic tubes, they may sag too much, unless I used fibreglass spreaders.

Don
m0hcu

Good idea that:sunglasses:

Funny you should say that I can take my extenders out and add the shorter ones and have a 2m moxon or like you say a 4m moxon as well, just need extra wires made up. Mind is 20mm conduit piping the harder one of the two. But again keeping it light weight. and the center bit is an old chopping board

Good what you have done and thanks for sharing.

karl

I opted for the ready to go solution which tie wraps onto my backpack. I don’t recall anyone asking about it, so I suppose it is easily recognised as an antenna. At 262g it weighs in at 100g more than yours, but I guess I can live with that. :slight_smile:

73, Gerald G4OIG

6 Likes

Very neat idea, Gerald.

I went with the ‘spreaders’ simply because it was going to be used on my travels, They fit very nicely into the same plastic bag that the travel pole fits inside. and the centre just gets packed in with all the other rubbish in the case :slight_smile:

1 Like