Monday 26 March 2012

Hawaii Emergency Radio Club End-Fed Antenna

What on Earth does Hawaii have to do with Wales?  Well, as far as supplying excellent, simple - and above all - cheap antennas is concerned, actually quite a lot.

Given the simplicity of the first random wire I used, and its success in getting to VK land on just 50W one morning, I was reluctant to give up on end-fed wires altogether.  What was needed was one that didn't radiate in the shack and occasionally cook my PTT finger!


An idle search on the internet turned up the Hawaii Emergency Radio Club 40-6m end-fed wire, which has a simple 9:1 transformer, helping keep the antenna under good control.  The club makes these as finished items, but they also provide clear instructions on how to make one if you prefer.  I just paid the money on ebay!

A few weeks later, slowed down by the pre-Christmas post, the wire arrived.  I strung it up in minutes as a sloper, but it didn't seem to be as effective as I'd hoped, even though it could comfortably handle 100W as opposed to the 50W my 'wild-fire' end-fed could work.

One day, I struck on the idea of stringing the wire up a fishing pole to make an end-fed vertical.  I had no idea whether or how well it would work.  Did I need radials?  To hell with it!  I fired-up on 10W and no radials - no problem.  Then 50W - still no problems.  Then 100W.  Again, no problems.  It tuned beautifully and easily on all bands to less than 1.3:1.  It pulled in stations from across Europe and out to Asiatic Russia quite readily.


Then, around sunset, I heard a ZS calling CQ North America on 20m.  I'd ordinarily have respected his wishes, but somehow felt the signal would make it, and at the time, ZS wasn't being heard that much.  I called him anyway, and he was good enough to respond very politely.  The $40 Hawaii vertical on a $30 fishing pole pulled in a 58 to South Africa.  I was very pleased with that! 

'Simple' verticals give you low radiation (depedent on band and environment) - something not to be sniffed at.


Soon after, and to my considerable amazement, I got through a pile-up with this bit of wire to Japan - a 57 was reported!  I have since tried it with radials, but I haven't done any robust tests yet.  It probably improves the efficiency a bit, but so far, I can't see any apparent difference.

At some point, I found this excellent video which, like me, gives you a 'real world' feel for what the antenna can do, as opposed to moaning about its performance relative to a big yagi.  Unlike this video, though, my assessment is based on 'phone working:



Oh, one evening, on 40m, which isn't a band I'm otherwise equipped for (the 20m delta will work, but not very efficiently), well-known seafarer Ginel - YO4RYU/MM - kept in touch on his way across the Atlantic, near Bermuda, by my using this antenna.  The signal was much better both ways on the vertical than the delta.  Again, it might not be a cubical quad, but it allowed a good contact to be made.

Keeping in touch with Atlantic-crossing /MM, thanks to the Hawaii vertical.
And then, during an early-morning session in February, my old mate ZL3OZ responded to a CQ call on 15m!  I was only about a 41, but even so, keep in mind how simple this antenna is, that it has no radials, and cost a pittance.  When I switched to my 15m delta loop, the signal jumped to a 557.  Again, that antenna was put together for peanuts.

A photon emitted by a simple vertical antenna in Anglesey arrives in New Zealand.  Pretty amazing!

Yep, I agree entirely with those of you who will say a 41 on this vertical, or a 57 on the delta, is not a very blistering performance.  But you see, those people miss the point that for a new amateur operator - and some not-so-new ones, making the contact is the amazing thing.  When it's done with so little money compared to a commercial product, then it's even more rewarding.


And do keep in mind that the propagation has an awful lot more to do with whether - and how well - you are heard than many - especially those who spend a lot on the hobby - seem to want to accept.

Indeed, what I've come to realise is that it is the skill and timing of operation that is the crucial thing.  Don't get me wrong - my delta loops have bust pretty big pile-ups quite often - they are certainly not in any sense a useless antenna.  But if you avoid the shoutiest of pile-ups, operate during quieter weekday mornings as opposed to contest-ridden bands during the weekends, then you will soon start to realise that even the 'simplest' antennae can very easily make global trips and allow long, meaningful QSOs to be held.

The Hawaii end-fed - up a fishing pole in Wales - and out to the world!

Sadly, the remorseless advertising, materialistic approach and the macho need to build ever-bigger stations with ever-more power is, in the end, simply taking amateur radio backwards, not forwards.  There is little to be proud of when 1500W through your 7x7x7 yagi array at 50m is causing splatter across a huge swathe of the band half way across the world.  That's just daft - and unnecessary.

And, inevitably, when someone like me sends a positive report of the Hawaii antenna to eham, someone else then finds it was useless.  That's the internet for you; lots of opinion, no consensus!  My tuppence-worth?  I think you can afford to have a go, see what it might do at your QTH.

UPDATE: (4 years later!)

Armed with a SARK-110 analyser, this is how a full HF sweep looks for the end-fed, attached to about 8m of simple hook-up wire, mounted vertically:

A reasonably high SWR across most of HF means good quality coax is recommended to limit feedline losses.

Monday 19 March 2012

Plotting My Progress

A break from antennas for this post!

It's pretty trendy in magazine reviews today to try and convey an antenna's performance by plotting contacts on a world map.

It's not a bad idea, but it does tend to perhaps exaggerate an antenna's performance, because reviews usually include a bit of CW operating, which is always going to be more capable than voice ('phone) communication.

I'm not a CW aficionado, and really only do 'phone work - I like some kind of idea of what the other operator is like, which CW isn't very good at doing.

But anyway, here's my plot of the areas covered (it only shows a tiny fraction of all QSOs to give an impression of 'how far' these wires can get), using 50-100W, and nothing more than a long wire initially, then a delta loop cut for 20m, and a loop for 15m (also operating on 10m), and a $40 Hawaii Emergency Club end-fed (vertical on a $30 fishing pole, no radials) for 40-10m operation.  One of those ZL contacts was initiated with the vertical; it was continued, with much stronger signals both ways, on the delta.  Long, reliable VK and ZL QSOs are commonplace.



Now, if you saw this map next to a £300 (or more!) antenna, you'd probably not hesitate to conclude, as the magazine reviews seem to hope you will, that it was a 'good' antenna and rush out with your credit card to buy one. 

But remember that my deltas cost no more than about £60, the 4:1 (which you can do without if you use a quarter wave 75 Ohm coax matching line) making up about £40 of this.  Once you're into radio, you will have these things to hand and will cost you almost nothing.

And magazines do, of course, always have to keep advertising income in mind when reviewing products.  As someone who's written a large number of expensive equipment reviews myself (not for amateur radio), I know that if a product is truly rubbish, a review simply won't appear.  There is always pressure with the rest to say as much of the positive and play down the negatives.  So objectivity is always something you have to keep in mind when reading any product review.  A magazine is nothing without its advertising, remember.

So, why not put away your credit card and just try something simple?  I suggest a delta loop is a very good place to start indeed if want to experience some 'real' DX.  You will not be disappointed, I can guarantee you!

Thursday 8 March 2012

Reduce, Reuse, Recycle.

If you ever find yourself with an antenna that's done fairly well, you're always a bit reluctant to pull it down, even if it's not the most sophisticated pile-up busting wire ever.

So it was just before Christmas with me.  I had my new copper tube creation, which was doing rather well on 10m, and which could be pressed into service on a couple of other bands at a push.

But the long wire, connected directly to the ATU and fed against earth, was simply too RF-hot in the shack, and far too wild to tune in a hurry.

You can see the delta - just - at sunset.  The next antenna can also be seen, but more about that later...

So down the wire came.  All 25-odd metres of it.  It was due to rain later in the day, so I decided I'd make a delta loop out of the old wire.  I took the measurements off some other person's web site, and attached the loop at its lower corner to a G-Whip 4:1 balun, perhaps the most robust and professionally-made baluns you'll ever find.  I tied it to a lashing wire on the chimney already, and connected the short length of coax.

The result?  Amazing!  Now DX was much, much easier, and I could even get into some pretty lively pile-ups, not that I particularly like those kinds of events - much too undisciplined for me.  Remember, this was with a triangular loop of wire and a 4:1 balun, with the apex at no more than about 7m, and no more than 100W output.  You also get much quieter reception than a dipole as a much-appreciated added bonus.

And, very importantly for this QTH, the delta is effectively immune to the effects of the regular 120km/h winds we experience.  It rarely gets into anything more than a gentle, low amplitude sway.

Soon, I was talking across the US, into the Caribbean, most of Latin America, even into New Zealand and Japan on long path.  Without doubt, this was the most unacknowledged, cheap,  top-performing DX antenna you could hope for, especially without the need for ridiculous mounting heights.

What's more, with a bit of help from the trusty ATU,  the loop can easily operate on 10m - as a solid 59 into Mauritius proved.  It will also try and work on 17 and 12, although with somewhat reduced performance.  The important bit is that, at a push, you can switch to most bands with this loop and make a contact - it's better than just sitting there, listening and unable to at least try and make a contact.

If you think deltas are just simple wire loops and of little better gain than a dipole, well, technically, you'd be right.  But if you think they are of no use, you'd be very wrong.  True, I'm helped to the tune of many dB - anything between 6 and 12dB - by the nature of the surrounding landscape.  But deltas perform very well in most situations and, being very slight (you can use very thin wire with deltas if you wish), very neighbour-invisible.

So go try a delta today!