Vertical antennas perform best in low radiation angle DX, when they are placed on a high conductive soil. For example soil like wet farmland, swampy soil or rich soil with a high concetration minerals. But the best ground would be large silver plate but that would not be very realistic. However, there is a type of ground that is so conductive that if you place a ¼ wave vertical on it, it can compete with a 3 element Yagi at 10m height. That ground is called: Salt Water. But what has that got to do with the Island festival?

WWRO Island Festival is an annual event where operators activate islands. The festival goes along with a kind competition: Work as many activations as possible. Every year I wanted to join the competition, but other obligations always prevented this. But this year I am in, and with a special setup! My country is surrounded by sea, so a great opportunity to operate and test verticals near salt water. There are certain locations where you have salt water 270° around, and such a location will be my portable setup for this year.

Instead of placing a vertical near the shoreline, I am actually going to have a vertical floating out in the sea on a small wooden boat about a wavelength from the shoreline, using the entire North Sea as my counterpoise. At the sametime another vertical will stand on the beach, also about a wavelength from the shoreline. That will give me a nice opportunity to test both setups, and see if floating out on the sea produces even more dB’s gain

I will be out there on 2nd June!

Those who are daily active on the band must have noticed that propagation was relatively good even excellent during the 3^rd and 4^th quarter of 2011. The band was wide open, and I observed long path QSO’s, “around the world trip” echoes daily. In a “normal” cycle you would see months with high and lower sunspot numbers and average solar flux, but with an increasing trend. This cycle does things different, because in the last 5 months solar activity continued to decrease with an anticlimax this week when the background X-ray flux went below B-level, followed by a solar flux below 90. Does this mean that Cycle 24 passed it’s maximum?

Probably a few readers remind I did some precitions on the Solar Cycle 24 maximum on the PSC website. In the last prediction I stated that SC24 maximum should be around mid 2011 and not in 2013 as predicted by NASA and SIDC. That prediction was based on the migration of sunspots from. At the start of a cycle, sunspots pop out at higher latitude on the sun’s surface and as the cycle proceeds sunspots pop out more closer to the sun’s equator. Sunspots tend to move or “migrate” towards the sun’s equator. When sunspots pop up near the equator, the cycle is nearing the end.

Based on the data of past months I believe the chance that Cycle 24 will produce a second peak like in 4^th quarter 2011, is lower than the chance that Cycle 24 continues its descend to a new minimum. But what could that mean for the remainder of this cycle? This negative news is also positive news, because this weak cycle will end much sooner than expected, making way for Cycle 25. Although I do not have the right and compete data, the data I have suggests that Cycle 24 will reach a sunspot minimum in late 2016, early 2017.

But, there is a big BUT. Cycle 24 has surprised as many times before, for example the very steep ascend to the peak in Q4 2011. A new surprise, would not surprise me… let’s hope for it.

Lucky me!!! No better way to test the Moxon then with current conditions. Best propagation since 2003, definitely! I took the chance to do one on one tests, and results are a bit surprising in a positive way. But first of all for the right comparison:

The 2 element copper wire Moxon has horizontal polarization, is mounted at  almost 13m from the ground and is centred at 27.600 MHz. The ¼ wave aluminium vertical with four sloping copper wire radials has vertical polarization, is also centred at 27.600 MHz and the feedpoint stands 11m from the ground. At the centre frequency SWR of both antennas are near 1:1. The Moxon is fed with RG-213 coax and a few meters of RG-58 near the rotor. The vertical is fed by RG-213 coax, which is 4m shorter in length. Both antennas are mounted on top of the roof of a brick house in a dense populated area.

First series of comparisons is gain over different path lengths (e.g. different radiation angles). For the high radiation angles I choose stations in Greece, Bulgaria, Russia, Southern Italy, Southern Spain, Finland and Norway, all path lengths of about 1800-2100km. For the low radiation angles I choose longer single and double hop paths to stations in North America, Africa and Asiatic Russia with typical single hop distance of >3000km. In all cases the Moxon was definitely a winner, with at least 6dB (1 S-point) up to 15dB (2.5 S-point) gain over the vertical. There was no noticeable difference in gain between low and high radiation angle, but interesting was the gain of over 20dB (> 3 S-points) over the vertical on certain paths in northern direction like Pacific and Norway. I do not have a good explanation for this, but it could be due to the fact that in that direction the Moxon is looking out over an area with almost no buildings.

The front/back ratio of the Moxon is average about 20-25dB (3-4 S-points). Remarkable was the front/side ratio which was average 15dB, much lower than I expected and measured before! But the actual “null”  on the sides was not at a 90° and 270° angle from the front but more at a 60-70° and 290–300°angle, suggesting that at 90° and 270° angle from the front there are two small lobes instead of a null. But these side lobes could be caused by the vertical antenna that stands in a 5m radius from the Moxon. What I will probably do is to ground the vertical when I switch over to the Moxon and vice versa, this way none of the antennas should interfere as a parasitic element.

I did a setup with a dipole and the Moxon to compare the both. Unfortunately the antennas were too close, resulting in too much interaction and high SWR. I turned the dipole into a vertical and it looks like both antennas like this setup more. Next weeks we will do some comparison test and will have some interesting results.

It is a long time ago since I heard the North American westcoast on 11m. Well, past few days they have been on the air every evening, and conditions became better by the day. I managed to work some guys from California up to the state of Washington. Have not heard any Alaska yet, but propagation might have been there while I was enjoying dinner.

Something remarkable is that I am beginning to notice that the Moxon is behaving differently after or during rain. Could be that rainwater on the roof is altering the radiation pattern, so that is something interesting to investigate.

I am thinking of taking a day of soon, so I can drive my car to the beach to setup up a vertical array of two 1/4 wave groundplane antennas near the shoreline. Near salt water, that should work even better than an advanced 3 element Yagi. Perhaps after the weekend of 23rd October, as I expect some more solar activity around that time.

Well well, if you want something so badly, you gonna get it. And I mean propagation… Finally some great conditions, and a perfect opportunity to do some more testing on the Moxon. Saturday started with nice paths opening into eastern Asia en Australia, and during the morning conditions seemed to keep improving, even with K-index at 4!

In the afternoon 38/47DX101 came on the air, and  after I worked John, his loud (S9) and low QSB signals turned out to be a very good beacon for testing the Moxon’s F/B ratio in different configurations… Thanks John! I got the Moxon now at about 25dB F/B ratio, but I believe it can be a few dB better. Testing continues.

Next weekend I am going to try digital mode PSK31, and see if I can make some nice contacts.

Since a few weeks the 11m Moxon is up and running. It was quite an easy job assembling and mounting it. I have constructed it in a way that makes it very easy to assemble and disassemble it in case of a severe storm (which happens here frequently). From a mechanical point of view, it’s a relative flexible construction which moves around quite a lot when it’s windy, but this flexibility has a big advantage. Recently we had quite a storm with gusts up to 95km/h (60mph), and the flexibility of the Moxon was the reason it wasn’t blown of the roof. The turning radius is just over 2m (7ft), which is much less than any fullsize Yagi, making it also ideal for limited space situations. Mechanically I’m very happy with the result.

Last few weeks conditions have improved significantly, but busy at work an at home, I did not have very much time to do some extensive testing. But, I have been able to make some nice contacts, and the firsts results are quite impressive. The gain is OK, averaging around 6dB better than my vertical and the F/B (front/back) ratio is somewhere around 15dB. I am still working on the space between the ends of both elements, tuning between 10cm (4″) and 20cm (8″). Getting the right dimension should increase the F/B ratio to 25dB at least. The impedance is 50 Ohm straight on the radiator, which means a matching device like gamma match is not needed, so no electrical losses there. The bandwith is what impresses me most, SWR is under 1.5 from 27.000Mhz to 29.000MHz, covering CB, 11m and 10m band! There are not many directional antennas that cover these three bands without the use of an external antenna tuner.

As we are moving to winter here conditions should improve, so I can do some more testing in the next 6-8 months. I will try to set it up against a dipole to see how it performs exactly. Next year I will extend the Moxon with another 2 elements to make it a 4 element, adding another 3dB extra gain.

I am quite sure now that the Moxon is probably one the most ideal directional antennas.

A detailed view on the spreader mounting to the rotor mast. All done with commercially available materials.

With 6 turns of RG-58 A/U coaxial cable in a 10cm (4″) diameter, this choke balun “chokes” currents running on the coax’ outer shield, preventing nasty interference on electrical home devices. The end of the coax is connected directly to the radiator.

Standing almost 13m (43ft) above the ground, the 2 element Moxon is still a quite low profile antenna.

Well, I got all the materials for the new 2 element Moxon, a more ridged than the previous one that was blown of the roof… This time I am using 20mm PVC tubes as spreaders. I have attached the spreaders to a mast made out of a piece of curtain wood. The spreaders are mounted onto two rectangle pieces of Trespa panel, with hydraulic line mounting clamps. The wooden mast stands on a TV antenna rotor which is mounted onto a 5 meter piece of aluminium tube.

The construction is up but I still have to fix the elements (pieces of old loudspeaker wire) onto the spreaders. Fortunately weather has been very bad, lots of rain, too windy, and the forecast are not very good. So the Moxon antenna will probably be operational next Tuesday or Wednesday when better weather conditions are expected.

As soon as things are working I will post some pictures.

Finally after a few years, I have my own website online. I decided to make a combination of a simple informative website with a blog. Feel free to post any comment on my blog. Happy reading and good DX!