How To Build A 6m Moxon Antenna For The Magic Band

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During the 2005 sunspot maximum, global 6-metre propagation reached extraordinary levels, rivaling—and in some cases surpassing—the performance of HF frequencies in certain locations. This remarkable behaviour, where the VHF 6-metre band exhibited propagation characteristics typically associated with HF, earned it the nickname “magic band” among amateur radio enthusiasts.

I have always been an enthusiast for VHF and UHF. This stems from the days when I first obtained a “B” class licence in the UK in the late 60s. In those days, you had only two options open to you. You could take the RAE and the morse test to get an A licence , or, if you didn’t take the morse test you could only apply for a B licence.

The difference was that an A licence allowed the use of all HF and VHF bands at 150 Watts (the odd band had lower maximum outputs), or with a B licence – same RAE – you were restricted to UHF only. Nothing lower than 430 mHz.

I was working for companies in my day job who used only VHF and UHF so this was my main interest. I could not be bothered trying to build big antennas.

Times Change And Bands Change

The B licensees were later offered the 2 metre band and this made big changes to our equipment and antennas. Later 4m and 6m were added to the B licence.

Further down the line, the authorities recognised that CW use was falling off and that B licensees were just as capable technically, having taken the same exam as A licensees and the B licence was finished. All original B licensees became A licensees. We now had the full gamut of frequencies.

I became interested in 6m when a little portable 6m Yaesu FT-690 RII came my way in a part exchange deal at my RIG DOCTOR radio business. With a only a 2 element antenna I began working European stations on only 5 Watts. This band was MAGIC.

In the northern hemisphere, activity peaks from May through early August, when regular sporadic E propagation enables long-distance contacts spanning up to 2,500 kilometres (1,600 mi) for single-hop propagation. Multiple-hop sporadic E propagation allows intercontinental communications at distances of up to 10,000 kilometres (6,200 mi). In the southern hemisphere, sporadic E propagation is most common from November through early February.

I have been a fan of 6m ever since and quickly acquired an FT-736R which covers 6m, 2m and 70cm.

I moved to a new QTH several years ago but no longer had an antenna for 6m so when the bug bit me again, I looked around for something to make a 6m antenna from. I quickly made up a half wave vertical just to see how the band was. I had a contact over about 1000 km in the first hour of switching on.

DIY Materials For A 6M Moxon Antenna

That was enough. I was into 6m again. I needed a decent Moxon antenna. My local DIY yielded little of interest with which to build an antenna until I found the yellow gas pipe used for connecting from the gas main to the house. This is fairly rigid and relatively cheap. It also has a stainless steel lining so is effectively metal tubing. I deal for a 6m Moxon antenna.

The outside diameter of this pipe is about 14/15mm but the stainless steel pipe inside is about 12 mm si I used the dimensions for the steel rather than the outside plastic coating. These dimensions worked out beautifully in practise.

The Moxon antenna is a full wavelength antenna so six metres of this would make a Moxon for the 6m band.

The gas pipe is three layers. Yellow plastic, stainless steel and black plastic.

The Moxon antenna requires two side insulators and I found that the 15mm yellow gas pipe is a tight fit into WHITE PVC pipe used for water. The GREY PVC pipe has a different internal diameter and the yellow gas pipe will not fit into it.

I cut the three pieces of gas pipe I needed, bent it to shape as per the chart and fitted the two side insulators. I left a gap for coax connection of only 10mm and pushed the termination points into the third piece of water pipe (All dimensions are below).

Calculator For 6metre Moxon Antenna

Insulators For The 6M Moxon Antenna

Insulators consist simply of pieces of white plastic water pipe. Check before using anything other than the white one. The internal diameter of the grey plastic pipe is not the same as the white one which is large enough to take the yellow gas pipe. The grey one is too small internally.

Feeder cable connection dimensions

Moxon side insulator mountings

The Moxon antenna was screwed to a T shaped construction of 30mm plastic water pipe and checked for basic frequency settings with the MFJ antenna analyser. Surprisingly the SWR and impedance was fairly near the spot I wanted at 51 mHz although the antenna was laid on a wooden garden table , and I would have to check it properly in the air.

Mounting the Moxon antenna at about 8 mtrs from the ground, I connected the coax to the FT-736R via a decent SWR meter and pressed transmit on FM.

No output ! …. Why not?

A quick recheck of everything showed me the SWR meter was on reflected power. Switching to forward and full power, I found that the antenna was showing 1:1 SWR. WOW!!!

The analyser showed me that over 50 to 52 mHz the SWR is excellent at 1:1 throughout and slowly rising as I went up to 53 then 54 mHz.

As everything was from the local DIY store, who had never heard of 50 Ohm coaxial cable, I used 75 Ohm satellite cable to connect this Moxon antenna to the radio. I have no regrets. Everything worked out beautifully.

Yellow Gas Piping

I must investigate this gas piping further. I have a short length of 22mm O.D. yellow pipe marked HEATING MAX 95C which is extremely light, has the stainless steel inside and is so strong that I cannot bend it. I think this may become my 10m self supporting Moxon antenna if I can find the source.