Some members are building Hexbeams out of the cable access kits to be found at Aldi this month. Knowing that the Thornbury Aldi only had 6 packs left I went to the Bradley Stoke store to find they have approx. 30 left. So anyone wanting them get yourself down to Bradley Stoke.
Paul
M0ZMB
Friday 29th April saw the start of the TSGARC big Field Weekend. OK, not quite the same as its BBC Radio 1 namesake but just as much fun 🙂 Setup took place on the Friday and was finished by late afternoon – much quicker and more smoothly than last year. The event ran over the following Saturday, Sunday and everything was dismantled and removed by mid-Monday afternoon.
So a big thanks to those that came and who helped setup and/or remove everything. An event like this was only possible thanks to some accommodating friends of John, M6EQQ who allowed us to use their field. As a thank you the club bought them a bouquet of flowers and some beer. I will let you work out who received what! Like preceding days, the Monday was a relaxed start and the dismantle job only started late morning. Unfortunately, as some people know only too well it started raining just after lunch which incentivised speedy work. But some of us got a little damp – Rex 😉
Over the whole weekend there where two radio tents, the first used the FT-897 loaned to the club by Derek. This allowed HF and VHF (6m) operation using a G3TXQ Hexbeam from MW0JZE (top image). VHF (2m) operation was possible using a 9-element Yagi from Tonna. The FT-897 PA provided 100w on HF and 50w on 2m. The highlight of the first day was a solid 17m contact into Japan by Derek using SSB. But there where also lots of other contacts across the European and American continents. The hexbeam was observed to have useful directivity mounted at 12m atop the trailer tower.
The second tent used a home-brew HF (20m) Bobtail – orientated to provide East/West lobes – and a 3-element Yagi for 2m, both courtesy of John M0HFH. This tent used the clubs FT-450 both for SSB and CW plus an FT-857 and FT-817 provided by John and Rex. The tent also showed rebellious tendencies, opting at times, to use some rather exotic batteries which no-one wanted to be anywhere near!! Thanks John!
There, was of course, another tent, a very important tent and one where people congregated. The ‘brew tent’ was where we had the stove, tea, coffee and what seemed like an endless supply of bacon – thanks Jane – plus copious amounts of biscuits 🙂 The weather was mostly dry but a little on the chilly side so this was indeed a popular tent.
In total we had two big (6m x 4m) tents, the rebellious tent (2.5m sq) plus a small day tent to keep the generator dry. These provided ample space and shelter for the weekend. The final accommodation to mention was the chemical toilet, arguably the most important item to making the field weekend possible.
Everyone who went had a good time and all the equipment worked well. Simultaneous operation of two HF stations was not really possible, or expected, due to the proximity of the antenna’s so perhaps a project for next time is to make band-pass filters. It was a surprise to find that even HF low power transmissions broke through on the other tents VHF (2m) activity.
With only two radio’s in operation at any time it was common to find people in the ‘Brew tent’ or contributing to activities in the field. In the above image John, M0HFH is being helped to connect an ATU to the feed point of the HF (20m) Bobtail.
There was also some genuine help. Many hands made light work of jobs including raising the tents and preparing the operating positions. Unpacking, assembling and raising the hex beam was made easy with great support. Thanks also to Ron, who stuck it out in the rain on Monday to methodically dismantle the hextbeam such that it can be easily reassembled next time.
Personally, I’m already looking forward to another event next year. But we may move the date back to the late May Bank holiday weekend as the weather should be a little warmer 🙂
Andrew
G0RVM
Hi Andrew (G0RVM) here… I really enjoy working HF portable due to a home that’s in a noisy urban conurbation and the joy of being out in the country, often with seriously impressive scenery all-around. This post is about my recent purchase, a MW0JZE constructed G3TXQ Hexbeam antenna.
Up to now I’ve been using simple wire antenna’s such as monoband dipoles and delta loops strung over or between portable fibreglass telescopic masts when operating portable. Due to the exceptionally low noise floors found at portable sites I can hear just about anything if its there, but its difficult to get heard due to the negligible gain of simple antenna’s. Enter the hexbeam, a 2-element Yagi for 6m, 10m, 12m, 15m, 17m and 20m giving useful forward gain (approx. 3 to 3.5dBd), a good front to back ratio and deep side nulls that should help during crowded band conditions. For example, a few years ago I planted a multi band vertical on the beach of a Scottish island. Yes, the antenna worked well, but it was just impossible because of very strong signals from all directions. Having some directivity and more importantly some useful nulls should greatly help.
Of course antenna beam pattern is not everything when operating portable; other significant considerations are the collapsed size, weight & portability, the erected size and finally ease of assembly/disassembly. The hexbeam scores highly on all these characteristics. Conscious that the Thornbury and South Gloucestershire Amateur Radio Club (TSGARC), my club, had a field weekend during May I decided to take the plunge and get a hexbeam in time for the event. The TSGARC as a 12m trailer tower so supporting the hex would not be a problem.
The hexbeam is not a complicated antenna and quite frankly I could make one myself, however, I wanted more than a prototype antenna, I wanted something that would cope with the vagaries of the English climate and was robust. i.e. it would stay dry in a wet English climate and would withstand multiple rounds of assembly/disassembly. Importantly, I wanted something which when arriving at a portable location was dependable. There are a few manufacturers of commercial hex beams and each seems to do a fixed and a portable variant. The portable versions are lighter and designed to fold. As my primary use was to be portable, a portable version seemed the right choice… However, I wanted something that was also robust and which could be erected full-time if I ever got a property where that should be possible. So I went for a fixed version!
After some Internet research I opted for one constructed by Anthony (MW0JZE) partly because of his good website, partly because of the excellent Youtube construction video’s but also because when we spoke he was very helpful and had experience of portable operations.
His antenna arrived in a cardboard box, inside everything was wrapped, even double and triple wrapped in news paper. Not quite what I expected and a real nuisance to unpack, but hey, you only unpack it once, the packing worked well and its eco-friendly – none of that plastic packing which is such a nightmare to dispose off 🙂 At home there is nowhere to assemble the antenna but I checked that the major components were present and just hoped the smaller bits and pieces (cable clips, nuts etc) were all present as I’d only find out for sure at the field event.
I need not have worried as everything was present, Anthony had even included some extra ‘wing-nuts’ as he knew my intention was to use it portable. So it was a warm, sunny Saturday when I constructed the antenna in a large field with plenty of space. From the outset I had a good feeling about the antenna as the build quality of the parts I’d seen at home was high. The fiberglass spreader arms fitted together perfectly, the arms into the baseplate and the radius and diameter cords just dropped into place. Anthony had obviously taken great care in its design and build.
As mentioned before, assembly was done in a field so it was a little disappointing that there were no hardcopy assembly instructions. Fortunately I had good Internet access via a TSGARC members cellphone and thus I could watch the assembly YouTube instructions. What would be really nice is if Anthony could supply the videos on a CD or include some instructions. Had Internet access not been possible, I’m confident I’d have worked it out, but having the reassurance was nice.
The antenna has a sexy blue engraved baseplate with ‘G3TXQ’ and a diagram of a hexbeam. It also has a large arrow with no associated text… I constructed the antenna as per the video’s (which didn’t show the arrow) but in haste I assumed the arrow indicated the forward direction of the antenna and thus mounted it to the tower so that the arrow pointed North. Wrong. If constructed as in the video’s the arrow points towards the back of the antenna 😉 Anyway, it was terribly easy to fix. Just a 180 degree rotation of the stub mast that fixed the rotor to the tower. This change took about 5 mins and that included lowering and raising the tower!
I purchased the toroidal choke balun with the antenna and this fixed to the centre post with a plastic clamp. There was a minor misalignment of its fixing holes but nothing a very slight enlargement of the fixing holes didn’t sort. On air, the antenna performed as expected; it demonstrated reasonable f/b ratio and good nulls to the sides. It was fed with around 400w and we received good reports from countries such as Japan, Argentina, Aruba, the USA, St. Helena Is to mention a few. So it worked and better than a wire dipole would have done I’m sure 😉 Perhaps next time I’ll do some side-by-side tests.
I pondered for some time the best way to dismantle the antenna at the end of the field event. I didn’t want to completely dismantle the antenna but only dismantle sufficiently to allow it to be packed and transported. It was actually a simpler problem than I had first thought. The element wires were disconnected from the centre post; the radius and diameter cords were disconnected; the spreader arms were disconnected from the base plate, the spreader arms were disconnected from each other and placed next to each other then finally all spreader arm parts were brought together in a neat pile. Finally the mass of spreader arms and element wires were dropped into a bag. The baseplate was left attached to the centre post. Next time it should be just a matter of getting it out the bag and reversing the process described above… Time will tell. 🙂
A good strong bag, something about 170cm long and 60cm in diameter with carry handles and compression straps would be an excellent addition 🙂
Thanks for the antenna Anthony, I’m really looking forward to using it again and perhaps performing a more scientific comparison with another antennas.
Andrew
G0RVM