Are we past sunspot maximum?

Just two days ago I published a podcast that looked at current solar activity and suggested that we are heading for a double-peaked solar maximum.

Two days later Tad Cook K7RA posted this for the ARRL:

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Much talk lately has centered around a possible dual peak in the current solar cycle. This would follow a pattern established in recent solar cycles. If this is so, the first peak probably occurred in the Fall of 2011. Now it appears that perhaps the second peak was in Spring 2013.

We are just a day away from the end of the month, so we won't see the actual averages until next week, but we can get a pretty close reading knowing the actual numbers for 29 of the 31 days in August.

The average daily sunspot number for the first 29 days of August was 92.2. This is above the levels for June and July, 80.2 and 86.2, but lower than April and May. This also pegs the 3-month average of daily sunspot numbers (centered on July) around 86.1, based on data from 90 of the 92 days in that period. This is above all of the three-month moving averages centered on September 2012 through March 2013, but lower than the previous three periods centered on April and May (106.4) and 97.5 for June.

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While working out when solar maximum is has always been an historical activity - you don't know you are there until some months later - this may not bode well for this Autumn. So start praying to the Sun Gods for more sunspots as an SFI of 100 is nothing to get too excited about.

But as I said in the podcast, conditions will improve naturally as we head towards late September due to a change in the ionosphere's molecular/atomic ratio (and therefore recombination rate) due to seasonal changes anyway. If you are looking for decent trans-Atlantic HF propagation it will be coming along soon. But we may have already seen the best of the decent 10m worldwide propagation - at least for another 10 years or so. Ho hum!

Podcast: HF Propagation, Autumn 2013

In this month's podcast I look at the current solar conditions and how the peak of cycle 24 may have already passed. I then look at what we can expect on the HF bands this Autumn and why conditions are likely to be better than they have been this summer.

Click on the headline to listen to the programme online or if you prefer to listen to it on your iPod search for G0KYA on iTunes.

Eliminating EMC problems

I gave a talk to my local club on eliminating EMC or RFI problems in the shack. This looked at how you can stop causing interference to yourself and to others.

It also looked at how electrical items around the house can also interfere with you (although I haven't included the videos in the attached PDF document).

These included everything from the washing machine (wipes out 30m) to the shaver charger (puts a noise out across the whole of HF).

Nevertheless, you are welcome to download the presentation handouts.

The “Kaz” directional MW antenna

The Kaz gives a deep null in one direction.

I have always had a soft spot for Medium Wave and a couple of years ago I decided to take MW DXing a little more seriously. The goal was to hear some North American stations – it couldn't be that hard could it? Well, yes it seems it could!

The first season saw me using my Icom 756 Pro 3 and my usual 80m dipole antenna, but nothing of any significance was heard.

It seems the 756 Pro 3 is deliberately deaf on MW and you can't use the pre-amp. I also listened on a portable MW receiver but that was no better, even with a small 12-inch Tecsun passive loop. The next season I used an RF Space SDR-IQ, but the pickings were thin.

So last year I upgraded to a Perseus SDR and a Wellbrook ALA1530S loop so that I could record the whole of Medium Wave two minutes before the hour to two minutes past to aid with stations IDs. Now we were getting somewhere, with WBBR 1130 kHz (New York) and NBC 1510 kHz (Boston) being heard regularly, although I wasn't hearing anything like the DX other MW enthusiasts in the UK were reporting.

 I actually monitored WBBR every hour, every night for two months to compare reception alongside the daily DsT index, but I can't say I saw a correlation. Anyway, this coming winter I'm determined to try harder and so I need an antenna that will null or attenuate signals from the continent. I ended up choosing a passive design called a “Kaz”, named after its designer Neil Kazaross.

Very simply, the antenna is part of the Flag/Pennant terminated loop family. It is an isosceles triangle with a base of 40ft and the apex at 10ft. One corner (FB) is fed with an impedance transformer and the other corner (TB) is terminated with a resistor between the two legs.

It actually turned out to be really good.

Read the full review of the Kaz antenna.

The secret of the Hately Cross Field Loop antenna revealed

Now it can be told – how were they built and what was Maurice working on before he died?

Maurice Hately G3HAT (SK)

It was with regret that I learned that Maurice Hately GM3HAT (and latterly G3HAT) had passed away. It appears that he actually died in the spring of 2012, but there was no mention of it in the radio press.

My interest in Maurice's work stems from my enthusiasm for small and stealthy HF antennas. As one of the pioneers of the very controversial crossed field antenna (CFA) theory, Maurice used to make and sell small loops for everything from Top Band to 6m.

His adverts regularly appeared in RadCom and I was lucky enough back in 2002 to review some of them for the RSGB.

BUT! This was on the strict understanding that I didn't reveal how he had configured the matching circuitry. I even had to promise not to break the seals on the boxes.

This I duly did and the review was written and published.

But now that Maurice has died I feel I should reveal how the antenna was constructed and also release details of what he had been working on before his death -  a new form of crossed field antenna that used two loops.

All this information may be too important to be lost and it is presented here so that amateurs can continue experimenting with his ideas. Was he on to something? Did his antennas work as as he said and can we continue developing them?

Steve G0KYA
June 2013

Download a PDF with the details of how the CFLs were built and also Maurice's last secret antenna design.

Practical Wireless 2m QRP contest

The 2m Moxon (arrowed as it is very small)

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I don't have a permanent 2m horizontal antenna installed, but when I was first licenced back in the 80s I did spend hours using 2.5W from a Yaesu FT-290R into a 4-element quad in the loft.

I used to work around the UK, as far as Norway, the South of France. Germany and Switzerland. Ah - good old days!

So for the Practical Wireless 2m QRP contest in June I thought I would have a bit of fun. I put up my 2-element home-made Moxon beam at about 8m on a fishing pole and used a Yaesu FT-817 running 2.5W from my Norfolk QTH.

I took part for a couple of hours and managed to work as far as Holland, France, Sheffield and Ditchling Beacon near the south coast. Also worked a few locals and into Cambridgeshire and Lincolnshire. Heard another guy near Cheshire, but he went QRT before I could get him.

Considering the size of the antenna I was amazed to work anything. Conditions were reasonable at first - I could even hear the GB3VHF beacon on a vertical dipole, but the band seemed to get worse by lunchtime.

All good fun though and happy to give away a few points. Nice to hear 2m SSB being used.

NEW! The multiband trapped EFHW HF antenna

The 20-17-15m trapped EFHW

Ever since I first published the details of the original monoband EFHW people have been asking me can you design a multi-band version? My stock answer has always been "no" – I couldn't see how I could.

Anyway, this had been bugging me for some time. I tried modelling a version that could use parallel-fed half-wave radiators, but it didn't work.

I had always dismissed traps as these are used on quarter-wave radiators so they wouldn't work on a half-wave design – or would they? Turns out they do. I started modelling an antenna in MMANA-GAL and found that you could make a 20-15-10m EFHW using traps for 10m and 15m. But you would need a variable capacitor to bring the EFHW tuning unit to resonance.

This actually makes sense as the end of an EFHW is at the same impedance as the end of a quarter-wave vertical, so a trap does the same thing on a half-wave design. All you have to control is the feedpoint impedance.

Doh! – why didn't I think of that earlier?

The result is my first working prototype of a 20-17-15m multiband trapped EFHW, which seems to work well. I have updated the PDF to show how this was done. Development work has continued and one can now be built with a single matching box that doesn't need a variable capacitor at all, just the original coax capacitor.

Download the PDF with the complete EFHW story.