CQWW CW contest was round the corner and every year, I try and give up after an hour because without a good antenna, it is often a frustrating experience. You "search and pounce" on a station calling CQ and they would answer someone else. You are never heard. Even if one has a $3000 worth radio, without a good antenna that can get signals in and out efficiently, it is just a piece of junk.

I have a poorly performing dipole for 40m and 20m. The 40m also tunes on 15m quite well. The contest happens on 160/80/40/20/15/10. Leaving the low bands, 10m seem like a viable band because of the current solar conditions and also because 10m antenna can be compact enough to fit into typical small urban Indian lots.

Last year I tried to get a 20m Moxon up, it didn't go up too much and within a day or two came down in the wind damaging some PVC water pipes in the terrace. This year, I had a better mast in the garage, donated by a fellow ham friend Siddhu VU2YYF, an avid contester. So, I had been dreaming about a 10m Moxon.

Shopping list

Last year's 20m Moxon was built with Decathlon fiberglass fishing rods. These when fully stretched out, provides up to 5m length, but the last 2 meters are thinner rods and are very flimsy and unsuitable. For 10m, each spreader length (None of calculators on the web gives this length, but for a constructor, knowing this length is important, so has to be calculated using the Pythagoras theorem) would be around 1.98m. I used my Moxon spreadsheet to calculate the length.

Apart from that, there is the center plate. I used the same old center plate that I had last year. One of the rods had broken, so a section of spare CPVC tube was cut and glued to that part before the U-clamps were fixed.

center plate with one of the spreaders installed

Another friend Vijesh VU3CAU came home on Friday evening and we made a trip to the local hardware shop and got some large diameter hose clamps to fix the mast. Unfortunately, we could not get stainless steel ones, which means, I still have a pending job to paint the MS ones we got. We bought some PVC pipes etc as well.

So the list is:

  • 6mm Aluminum Center plate
  • 4 Decathlon fishing rods with only the stronger two sections (enough for 1.98m length)
  • hose clamps for fixing the mast to any other supporting section. I had another iron structure in the terrace garden to which the mast could be attached.
  • 18/19 AWG multistrand teflon wires.
  • BU-50 Balun.
  • RF Cable (I used an existing RG-58U cable)
  • some lengths of PVC tubes to attach to the top of the mast to tie the four spreader arms. This purchase turned out to be of wrong dimensions, so was not used.
  • Some lengths of rope (I used a garden rope that was rated for use outdoors). The nylon ones would turn brittle after a few months of use.
  • nanoVNA or some other SWR measuring device.

The build

It was around 5.30pm already when we returned back home from the shop. We quickly put the basic antenna structure.

moxon with all the spreads fixed to the plate lying on the floor

The mast was in my garage and I carried it upstairs. However, it was already dark. But we persisted and tied the hose clamps and erected the mast and got the center plate also installed on it. I made some rough calculations on a piece of paper and cut the wires I had for 20m moxon to make it for 10m. We will come back to this later.

moxon with basic structure up, photo taken in the morning

By then it was already dark and we could not work on the terrace and decided to call it a day. Saturday morning would be the CQWW contest, but then it is just fun, so nothing is going to happen if we take a few hours off from contest to built the antenna.

Vijesh and I along with my wife and daughter had our dinner together. Vijesh left for the day. I went back upstairs to the shack and setup N1MM etc to get ready for the contest.

Next day, early morning, the contest began. I started with 40m. Vijesh came at around 10.30am. We started from where we left off. I had a large piece of plywood sheet and it came handy. It was damn heavy to carry it upstairs. But we could put it on top of the structure in the garden so that one could stand up on it. The structure is about 7 foot tall. We pushed the sheet up into it and got a 5 foot ladder that I had into the terrace. The metallic structure painted white (without the plywood on top of it) can be seen on the pictures.

I quickly took another look at the wires that I cut the previous day and once again did the calculations. I found that one of the wires (the reflector wire) was short by 3/4 of a meter or so. Luckily the wire that was cut the previous day was soldered in with heat shrinks to protect it.

Now the antenna is ready. antenna partly up. It was time to measure the SWR and at 28.000 MHz we saw an SWR of about 1.5 and it went down further as frequency went up. Good enuf! At least for the contest. We pushed the mast up a bit more. It is at about 12' height now. antenna at its final position


The 10m Moxon is nothing short of amazing! I made over 100 CW contacts on 10m with the limited time I spent in the contest with about 65W. I heard signals as far away as Brazil. I made contacts all over Europe, US, New Zealland, Australia, Japan and many more.. It was great fun.

cqwwcw scoreboard


I would like to thank Vijesh VU3CAU for helping get the antenna up. Without his help, it would have been a difficult task for me alone to get things done. Late Cebik's moxon articles were the ones that got me started on this antenna. A week before the contest, I watched a talk by John W6NBC. I wrote an email to John who kindly sent me the article he wrote for the ARRL "On the air" magazine. The measurements used the web based calculator on which has an error in its program, however the error is not big and the Cebik equations do not take care of velocity factor of the wires. Also NEC-2 and NEC-4 model for Moxon differs quite a bit (NEC-4 models are more accurate). Accounting for all that, the values output by tippete calculator is more or less the same as Cebik's calculator (+ VF of wire). My spreadsheet calculator gives a few CMs of difference in lengths. One has to experiment a bit. The length of the spacer (the piece of insulator that ties the folded parts of the driven element and the reflector) is important and the rest can be adjusted by elongating/shrinking the telescopic spreaders. I thank John for his kind email and timely help. Finally, I thank Siddhu VU2YYF for donating a spare mast which turned out to be solid. It is a military surplus mast and built well. I would also like to thank Saju VU3GNL for making the center plate in his workshop with a 6mm thick aluminum sheet.