“A Folding SuperMoxon for 2 metres” from Hugh, M0DSZ

For portable working there seems to be a preference for Yagi aerials, sometimes with a large number of elements. I find that these are easily damaged when attempting SOTA or backpack contests when it is not a straightforward ascent to a summit. Climbing through scrub or woodland and scrambling up rocks could form part of the expedition.

At home even, hoisting a VHF aerial up near a tree usually results in the tree being awkward so I developed a preference for folded aerials such as a Hentenna, Moxon and so on. Initially for field work, though, I used a folded dipole with reflector, folding a dipole also helps to raise the impedance when adding elements rather than fiddling with gamma matches. The folded versions are smaller and more robust than the conventional.

Recently there have been several designs for a “SuperMoxon” which is simply a Moxon to which is added a reflector and 2 directors. Modelling these, I found they did not correspond with anything I made or modelled so, having acquired a NanoVNA, I started on a folding “SuperMoxon” using 13mm and 10mm aluminium tube and I drew up the resulting dimensions which did not match models using MMNA-GAL.



The corners are made with 10mm tubing which fits tightly inside the 13mm tubing. I drilled and tapped the tubing once the dimensions were settled, fitted 2.5 mm stainless screws and left it thus but on a fixed version I used aluminium solder which is not the easiest thing to use, the technique is a little like jointing lead pipes.

Having some bits of fibreglass rod was handy for spacers but, as the device is not being left outside, dowel would be fine, or even old ballpoint pen cases.

Testing with the NanoVNA, I started with a short coax of some 30mm and then confirmed it was OK with 2.5m of coax, using 75 ohm TV cable gave the same results as 50 ohm low-loss.

From the photos, construction is simple, based on a bakelite strip cut with a small hinge added to enable folding. Some care was required to ensure the whole would fold flat.


The driven element ends fit into a small ABS box with lid and a BNC connector, this fitted to the underside. Also on the underside is a hardwood block, drilled to fit a pole and then sawn in two with long screws and butterfly nuts to form a clamp. Try to fit this at the centre of gravity, it makes usage much easier.

To keep the aerial folded up I used a long screw and butterfly nut, the screww is trapped in one section and a hole enables it to pass through the other section.