The initial experience of Innovantennas, a company with which I have never dealt previously (and of whom I am entirely independent), has been extremely good in all aspects. In particular, I was very impressed with Innovantennas' polite treatment of customers, even for a relatively inexpensive mono beam like this. Far too many other suppliers seem to take customers as some kind of hobby-mad idiots who'll part with their money, no matter what. So 10/10 for realising good service means continued purchases!
The antenna arrives (provided the couriers get their acts together between them!) in a very sturdy cardboard tube of about 2m long, which fitted in my family hatchback quite comfortably for the final leg home.
Out of the tube come several sections of aluminium alloy, some clamps and bolts. Instructions are sent by e-mail as soon as the antenna leaves the factory, and simply referring to the very clear, labelled diagram of the completed antenna was sufficient instruction. I had my antenna retapered to a slightly stronger tubing, and at no extra charge (which may not be available for all purchases!)
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| The 24MHz LFA yagi by Innovantennas pointing to the Far East. |
Fitting the antenna together is really very simple indeed - once you've sorted out all the bits. Each is accurately labelled with a marker pen, negating the need to measure, at least initially. But I would have saved a bit of time had each been colour coded. But this is just nit-picking.
Feedline connection is a direct 50 Ohm coax using loop connectors onto the shortest possible tails, with a coax common mode choke wound onto a piece of 4" drainage pipe (6 turns), according to the ARRL Antenna Book recommendations (the antenna instructions advise a much smaller diameter.)
One potential issue I identified straight away is the element-to-boom plates. Some manufacturers use clamps for this, and to be honest, I think that's a better solution than Innovantennas' couple of bolts through the plate and boom, though clamps do add significant weight.
Because the two plate bolts are drilled directly in line with one another, and have a significant degree of side-to-side movement when loose, this may give rise to skewed elements after years of buffeting in the wind. Time will tell. I did wonder whether staggering the location of the bolt holes would help, if they are to stick with this method of fixing the plates. Or maybe just tighter-fitting bolts? Indeed, after putting up the beam, there was a slight skew in the reflector plate which, though easily rectified, did necessitate some more tower luffing - never a welcome task!
I asked Justin, of Innovantennas, about all this, and his response was that the through-drilling makes for an easier build, free of measuring errors for the customer. It's a fair point, so I guess it could be a solution to retain this admittedly error-free system whilst perhaps having a guide - even if it's just a shallow recess milled into the plate - to help stop any skewedness. Justin says that "wide washers" are supplied to help secure the load, but the ones I had with the antenna were barely larger than the nuts, with the result that some very minor deformation of the boom was evident. Only the split-boom securing bolts had wide washers. The next time I luff the tower, it will probably be worth fitting some wider washers under the element-to-boom plates.
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| Not bad for a first QSO! Wales to UA0FA, Sakhalin Island (3700 miles) on 15W PSK-63 |
One thing to look out for when assembling is not to stick everything together to see what it looks like first! In my case, I bent one of the split ends of a tube whilst moving the partially-assembled loop onto a stand, which could have led (but didn't) to a failed or fatigued element tube, although they are easy to replace. Set out to assemble the antenna on a fine day, with everything you need to hand and do everything nice and sequentially! You will need a whole summer's day if you take it easy.
Also make sure that, before you start assembling, you have a clear route to the tower, and for mounting it! It's really not funny when you suddenly tangle a big yagi in a stray wire antenna whilst trying to walk through hedges to the tower!
I decided to add some conductive aluminium grease (from Innovantennas), as heavily salt-laden air will corrode the antenna quite quickly, so it's sensible to give myself the best chance of removing an element easily, should anything break or I sell the unit later on.
Don't, as I did, add the grease until you've assembled the antenna and tuned it up properly. If you add it at the start, you'll end up with a horrendously gloopy, metallic grease all over your tools, hands, clothes and kids! Get everything working and tuned on the ground, then grease it up!
The standard loop connectors for attaching to the coax tails were too big for the job in my view. Being of significantly wider diameter than the bolts that run through them, they had too much potential to start working loose around the bolt. I replaced them with the correct diameter loop connectors which, though smaller, are no less sturdy. A small point, but we all know how 'unlikely' things become almost inevitable, once they are put up at height and inconveniently difficult to reach places!
Tuning was potentially a challenge for me, because the QTH is rather full of antennas, with a 15m loop being particularly close to the tower when that is lowered. I decided to stand the antenna on its end (it's fairly easy to move solo), and tune it in the 'pointing at sky' fashion, resting against a timber shed. This showed a near-flat SWR of 1:1 or less across the band - just like the marketing material claimed - though it did require a shortening of the driven element by a few percent - a total of 40mm altogether in my case.
I wonder about the robustness of the hose clamp fittings. These are punched-through thread types, which I know from experience can be significantly weaker than stamped/impressed threads. That is not to say they will prove to be inadequate, and if they do, they cost mere pennies to replace.
I got the antenna up on the tower and the SWR remained the same as it had whilst pointing at the sky on the ground. As any ham will tell you, an easily-tuned antenna really is a bit of a welcome relief, and should not be underestimated as to its value in avoided tower climbing or luffing, especially when working alone as is often the case.
Performance? Inevitably, I was up early the following morning and immediately and strongly (red waterfall line) receiving PSK-63 from UA0FO on Shakhalin Island on the Russian far east coast, followed by a much weaker RN0CD at a similar distance. The following morning, JA8EOT was thundering in, again 'red lining' it on the PSK-31 waterfall.
Later in the day, I'm now busy working the US well into darkness on 12m. A Florida op was laughing with surprise that I had "such a great signal", even though the beam was aiming considerably north of him!
All this with the tower merely at its fully lowered, 5m height!
One other major tests to pass at this QTH is high wind tolerance. We can experience winds up to 80mph at any time of the year, but winters now bring up to 110mph in gusts, which are usually the most damaging aspect of gales. Already, the LFA has flown in gusts of around 55mph, and does nothing other than gently ripple; no sign of excessive vortex shedding or other such nasties at all. Obviously, if you can luff your tower before winds are likely to be particularly bad, it's probably best that you do so, especially if your location receives turbulent winds, which are more damaging than a strong, steady flow.
So, whilst there's plenty of on-air testing to be - and will be - done over the coming weeks, the responsive, polite customer service, ease of build, ease of tuning and overall quality get a big thumbs up in favour of Innovantennas. Just maybe have a think about those element plates-to-boom fixtures...
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