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.

International Marconi Day, April 20 2013

Saturday 20th April 2013 is International Marconi Day when stations around the world celebrate the birthday of Guglielmo Marconi.

It is also a good opportunity for you to gain a very nice certificate. All you have to do is work the requisite number of award stations and send in a log extract - you don't need QSL cards.

I am giving a talk to Kings Lynn Amateur Radio Club about the best way to win the award and you can download the presentation in PDF format (14Mb). It is aimed at UK operators.

I shall be helping to run GB0CMS again this year at Caister Lifeboat. There is short video that looks at the equipment the club used to make 165 contacts in 24 countries on Saturday 30 April 2011. And another for the 2012 event when we made more than 500 contacts.

See http://www.youtube.com/watch?v=Z41FLKaT7eY and http://www.youtube.com/watch?v=C8ZRW0q6SyI

You can also view my propagation predictions online.

You can find out more at: http://www.gb4imd.org.uk/

Origins of the term "CQ"

Have you ever wondered where some of our radio terms come from?

Some say that SOS stands for "Save our Souls" - which it doesn't. The Morse phrase ... --- ... was chosen as it was very distinctive and unlikely to be misread. It doesn't stand for anything.

So what about CQ? I've heard it described as "Come Quick" but that doesn't make sense.

But a chance conversation with someone while working in the US has cleared this up. He is multi-lingual (unlike me) and although he is not a radio ham, knew immediately what it could stand for.

CQ is Cherche Quelqu'un - literally the French for “looking for someone”

This makes sense as a lot of radio terms have French origins - the Coastguard still says "securite" for important information.

So there you have it - the origins of CQ. Or is it?

Pol G3HAL sent me an update. According to Wikipedia:
Land telegraphs had traditionally used "CQ" ("sécu," from the French word sécurité^[1]) to identify alert or precautionary messages of interest to all stations along a telegraph line, and CQ had also been adopted as a "general call" for maritime radio use. However, in landline usage there was no general emergency signal, so the Marconi company added a "D" ("distress") to CQ in order to create its distress call. Thus, "CQD" is understood by wireless operators to mean, "All stations: distress." Contrary to popular belief, CQD does not stand for "Come Quick, Danger", "Come Quickly: Distress", or "Come Quick — Drowning!"; these are backronyms.

This sounds more likely.

The Morse Crusade

I had an email today from Ian G4XFC, founder of the Morse Crusade. This concentrates on the Koch method of teaching Morse. The Crusade has been running since September 2011 and is starting a new campaign this year to promote the learning and use of good readable Morse.

Any site that promotes the use of Morse code is good in my eyes - I use Morse a heck of a lot and it is my favoured mode for working DX, although I struggle with my speed increasing and decreasing as I either use it more or let it drop for a month.

I've worked some choice DX that I would never have been able to work with SSB, using up to 100W CW and an assortment of compromise antennas at this surburban QTH. This is what prompted my "Stealth Antenna" book.

Anyway, you can find out more at www.themorsecrusade.g5fz.co.uk