Spiderbeam Pole Clips

A long time ago, I discovered that silicone rubber, from old egg microwaving cups, lying beneath a jubilee clip was a very good way to stop fishing pole sections from slipping.

So good is this system, in fact, that a pole will snap in heavy winds before the pole sections ever slip (and that's from experience!)

But the problem with my egg-cup silicone clip system was that you had to remove and relay them every time the pole went back up again.  That means you become lazy and avoid pulling it down, for not wanting to go to the hassle of doing the work all over again the following day.  Sometimes, laziness leads to broken poles!

If you use the recommended length of shrink tubing, it always creases-up hard like this.

So, I decided to buy some good-looking clips from Spiderbeam in Germany.  Price reasoanable, but it does mount with postage costs on top.  The kit of clips I selected was the one for the 12m Spiderbeam pole.  As I haven't got a Spiderbeam pole, but just a normal cheap fishing pole, a couple of the kit clips are thus redundant.

A few days later, much to the credit of Spiderbeam and the postal systems, the clips arrived.  What are they like?


Well, the clips are nice quality stainless steel for starters.  Important for a pole which in my case gets covered in salt-laden air every time it blows a gale (even though we're a few miles from the sea!)  Unlike shop-bought stainless steel clips you tend to get in DIY stores, these clips are not too thick and hard, so they are quite easy to bend.  But you can find identical, quality stainless clips on E-bay...

As for the rubber padding, this was a bit of a disappointment. You have to cut the rubber strip into the correct lengths yourself, for which a table of measurements and admittedly very clear instructions is provided, should you somehow be unable to just do it by eye.  Then you are told to slip a slightly shorter length of shrink tubing over the rubber and clip, so that this keeps it all together.

It occurred to me that shrink tubing isn't particularly designed for external use, where it will be exposed to strong sunshine for a number of years.  I looked this up on the 3M site, which seems to say, in a rather convoluted manner, that black shrink tubing only has limited UV resistance.  The saving grace is that it's very easy and very cheap to replace it if it does crack after a while.   In practice, I'd just replace it with PVC tape.

The simple solution to avoid creases is using a series of shorter lengths!

Don't get me wrong - this is a system that is perfectly fine, and works a treat and the clips grip that pole much better than my egg-cup silicone system.

I found the instructions to cover almost all the rubber with shrink tubing to be problematic in that once you fasten the clip, the tubing inevitably wrinkles up as the circumference reduces, leading to quite stiff creases on the inside face of the clip.  Whilst these probably won't damage your pole, they are very unwelcome and partly undo the benefits of using soft rubber padding.  Spiderbeam does say in the instructions that creasing may happen, but that applying some more heat will "easily" remove them.  In reality, added heating makes very little difference once hard creases have formed, and then they just stay put.

Voila!  No more creases!

The solution to this is as simple as it is odd that Spiderbeam seem not to have cottoned-on to it.  Instead of using a long length of tubing, just cut up three shorter sections of about an inch or so.  This entirely avoids the creasing problem whilst still allowing the rubber to be held very securely in place (shrink tubing is pretty strong stuff!)

In summary, the Spiderbeam kit is not an unreasonable one, and contains all you need to make good fasteners for your pole.  The clips have a very well-formed running thread but aren't cut through like cheaper clips, which fail quite easily, having been weakened. 

But you can get the same clips for about 75p each (E-bay, etc), soft rubber costs next-to-nothing or can be found around the house, and electrical tape is just as good to keep the rubber in place.  So, you could save yourself maybe £15 or more on the Spiderbeam kit if you make your own.

Normal recommendations are to place the clips on the bottom of each section, butted up against the top of the one below it.  This is what I have always done, and it works fine.  But it has set me thinking, because poles almost always split from the top of a section as a result of over-stressing in strong winds.  I do wonder whether an additional set of rubberised clips might add a little strength to the pole.  Until the pole breaks, I'm making-do with a well-wrapped preemptive layer of Duck Tape around the top of each section.  Using this tape to repair an already badly split 10m pole has kept it in service for about a year already, so don't throw your snapped poles away too quickly!

RadCom - February 2014

RadCom, February 2014 edition just landed.

Will it be another case of impenetrable writing on an equally impenetrable topic, or will there be signs of improvement?

Well, fair play, this edition has a lot of good writing.  Top of the pile is certainly the expansive section on moonbounce by, the magazine gives, G4ZTR and G4SWX.  A very successful blend of basic concepts and moving on to cover in sufficient detail the type of equipment and results that can be expected.  Not that setting-up for moonbounce is particularly affordable, but that's another story.

The Moonbounce article style is what RadCom should strive to attain.  It will, however, find this very difficult unless it abandons the rather lazy idea of waiting around for hams to send them print-ready articles.  It needs to develop a 'house style' that is consistent and appeals to a wide and not just highly-niche readership.  This probably means paying people to write, so that those that can write do so, whilst those who glory in thinking they're a successful author when they are anything but are dropped.

Now, the good news keeps coming with a nice little article on ARDF by G3ORY.  I chuckled at the very enthusiastic face of a schoolboy, whilst a girl slightly in the background (unfortunate), looks as if she's saying "what's the point of this, I can't hear anything anyway.  Again, unfortunate.  But the text makes ARDF appealing to everyone, which is what we want to see.

Neither this month nor last could I see much point in printing a talk given by some bigwig, whose credentials take up three quarters the width of a page (does Prof. Cochrane think we are impressed?), about "One Future" for amateur radio.  Sounding a bit like a Labour Party catchphrase, the article is really dull, and entirely unrealistically, fails to make any mention of the catastrophic drop off in numbers the hobby is almost inevitably about to suffer in the coming few years.  It's very old boy RadCom, I'm afraid, Prof.

Next we come across a much-needed article on small loop antennas.  Covering this in detail could occupy RadCom editions for months to come.  But it's good to see a nice and well-written introduction by G3LDO.

The 'Data' section keeps providing sometimes esoteric but invariably interesting articles.

Then we move to making a loop antenna out of aluminium foil by G3PKW.  Great, user-friendly article, which shows you don't have to spend hundreds of pounds/dollars to get yourself an antenna that works very well (I'm a regular user of loops, so I should know!)

The rest is pretty usual stuff, but I continue to be very disappointed by the 'GHz' section, which seems to be steadfastly unwilling to start at the beginning and show a total novice how to get practically involved in those bands.  Again, with a bunch of men turning their back on showing newcomers the ropes, said men - and society - can only expect participants to dwindle rapidly as the years roll by.  That's a shame, more especially as it's this part of the amateur allocations that industry most wants to get its hands on.

Reviews of equipment made by regular advertising income providers to RadCom are as you would expect - not too much criticism and generally supportive of the idea you should buy said (expensive) product.

But in all, this month's RadCom shows real promise.  But can they keep it up? 

Being a 'Critical Friend' (Again)

Being a critical friend is often put forward as the right thing to be when governing a school or similar.  It's a good idea.

In that respect, I am what you could call a critical friend of the RSGB: I support it's existence and aims, but, quite often, not the way it goes about things.

No, not quite like that...

So, this evening, I had a look at the RSGB web site.  I looked under the "First Steps" heading.  There's been a bit of thought and change to appearing to look interested in newcomers, which is the first thing to note and congratulate the RSGB for.

But it's a bit of an uphill struggle from thereon in. I was surprised to read this:

"If you are reading this the chances are that you have just joined the Radio Society of Great Britain. You may now have your first amateur radio licence, or be thinking about studying for it, and are wondering what to do next.

In this section we look at your first steps into the hobby – working other local hams on 2m FM; how 2m SSB can get you contacts from further afield, and a brief introduction to some of the main HF bands and what you are likely to hear and when."

Hmm.  Apart from being rather odd in limiting matters to 2m working, why assume that people become RSGB members first, and then become operators?  Just about everyone I know did it completely the other way around. 

This is a very serious error indeed, because it makes people believe (is it intended to?) that you can only become a ham, or that you are only likely to become a ham, if you first join the RSGB.  This tits-about-face approach is plain stupid.

The RSGB web site needs to forget vested interests within the society.  It needs to squarely focus on grabbing the attention of 'drive-by' interest in the hobby for a few seconds more.  It's during those few seconds that a "maybe I'll look into this more" sets in.  We don't want to put 'oh, but first fill in this form to join a bunch of people with licences, even though you don't have one' in their way.  It doesn't work.  Wake up!

So, what I think we have ended-up with is radio second, RSGB first.  You can see the problem, can't you?  No radio, no RSGB.  That's why nurturing an interest in radio, and not in RSGB membership, must be the overriding aim.  The RSGB must have confidence that, once there is interest, once there is a licence test pass, most will, in the end, join the society - provided it caters for their interests.  And there's another thing...

Extension Speaker - Homebrewing Ol' Ned.

Ol' Ned, the speaker(s)

Listening to amateur radio signals with tin cans (headphones) is not always very pleasant, especially over long periods of time.  Tin cans also isolate you from other important duties, such as attending to matters when the XYL shouts for a coffee!  The result of not hearing can be disastrous.

So, for a while, I've been using these two speakers from a binned CRT television set, just hanging around on the desk loosely. Hooked up together, they form a nice 8 Ohm match to the output of the rig.

I've also been looking at the price of extension speakers.  They are not cheap!  A small desktop unit can cost well over $200, a classic example of "you will pay lots for any simple stuff because you are stupid, rich ham operator."

So, time to tidy up the speakers over the weekend, when I cut-up some old plywood and laminate kitchen flooring to come up with a cabinet for the two speakers that looks, in the end, rather neat.

I've named the unit  Ol' Ned.  Why?  Because it is internally damped with a large amount of horse hair - an excellent material for the job.  This was, of course, left over from lime rendering and plastering!

Total cost of Ol' Ned?  Zilch.  Result?  Brilliant, rich sound with much-attenuated high frequency hiss. The experience is much more like a landscape in front of you, rather than just plain sound.  Much better reproduction than even my best headphones, and doesn't hurt your head.  Unless you try to wear Ol' Ned around your ear.  In which case, it will hurt.  A lot.

UPDATE: I am listening to AP2MB, a long, all-terrestrial path to Pakistan on 12m just after my breakfast.  He is very weak, but readability 4 whilst listening on Ol' Ned.  I quickly switched to my best Sony headphones and...he is undetectable!  The difference between copy and no copy.  That's the power of Ol' Ned!

UK QSL Bureau: The Next RSGB Crisis?

The RSGB's QSL card bureau is, like all the others operated voluntarily across the world, a very valuable service with a long history.

But is there trouble brewing within the bureau?  Recent experience suggests there may be.

QSL Cards: Think before you send.

One bureau manager seemed, from the content of his e-mails, to be under quite a lot of stress.  He offered apologies when all operators were doing was asking for a general idea of when the next lot of cards would come through.  Whilst annoying to a busy manager, the ops certainly weren't complaining; offering an apology simply wasn't necessary.  Whilst a link between one thing and another is not known, a few weeks later, after the RSGB's duty of care to its helpers was pointed out to its officers, that manager is ending his hard work of very many years.

Now, the RSGB may well be doing 'health checks' on its QSL managers on a regular basis for all I know.  But I don't get that impression from those few managers I have been in contact with nor, it has to be said, from limited exchanges with the RSGB central bureau management.

In another example, a manager asked me if I really needed all the cards sent to my by one particular operator.  I was happy to to receive only one of the cards from the same operator if it helped some poor sod have a quieter Christmas. 

And then, just a few days later, I had a series of e-mails from a manager who was again exhibiting clear signs of stress in his wording.  I later learned he was disabled.  He complained that he should only be getting a couple of thousand cards a month, but was receiving five times that volume.  He, too, is now giving it all up.  One can hardly blame him.

So, whilst we all gleefully fill QSL cards by their hundreds, someone, somewhere has to sort them all out.  Whilst we may 'know' this, we operators don't seem to spare a moment to think about the welfare of those QSL managers.  I'm worried that the RSGB may also need to spend more time on its QSL managers.

It seems from recent experience that a lot of these people are, by necessity, very meticulous and methodical people, who may well be predisposed to worrying more about any inability to keep up with the volume of work.  That makes them vulnerable.  It means someone should, from time to time, be asking if they are coping.  Do they need help?  Do they, indeed, want to hang up their postman's cap?

There is no shame in being unable to cope with an unreasonable amount of work.  Especially when it's done voluntarily.  QSL cards are, in the end, only postcards that someone puts in a bin when you've finally gone SK.  It's worth remembering that sober fact, rather than assigning too much importance onto bits of cardboard.

If there is indeed a crisis out there amongst the various QSL managers, they would do themselves and the bureau some good if they all said "enough."  It will force a new way of doing things

Vacuum Capacitor - From Russia (Via Ukraine) With Love

For a long time, I've been looking out for a decent vacuum capacitor to reliably tune my 20m magnetic loop antenna.

At long last, and just before Christmas, I 'won' an ebay auction for an 'new old stock' vacuum capacitor, sold by stas3105, based in Kiev, Ukraine.

Now, you may feel a bit nervous dealing with Ukraine.  Happily, I can reassure you in that I've only ever had very good service from several Ukrainian sellers.  There seem to more ham operators in Ukraine than any other country on Earth!

Wow!  These Russian capacitors are huge!  They have a very good reputation for quality, according to fellow hams across the EU.

The capacitor, far from being some dodgy second-hand unit, really is in brand-new condition, liberally covered in protective grease and oil.  According to the accompanying leaflet,  it was made in 1990. It set me back a very modest £69, including the necessarily hefty carriage bill, the item being rather delicate.  I obviously managed to get a good price by buying just days before Christmas, when there was less interest than usual in this stuff.  It only took about a week to get here.

I happened to have a lot of tinned copper braid in the junk box, so this was ideal to make the connections, using jubilee clips to secure the braid to the capacitor tips.  It took a few minutes to find the correct tuning for the loop. 

WSPRing across the globe - 5W, 75cm off the ground in the kitchen!

Once tuned-up, the loop ran on WSPR for a few hours at 5W.  Unfortunately, the internet was on the blink most of the time, so only those stations hearing me are recorded for the most part.  Spectacularly, and again it was missed by broadband outage, I heard a signal from ZK1DRP in the Pacific Cook Islands.  That's pretty good going for a tiny magloop working indoors!

Magnetic Loop Antennas - Why You Should Have One.

Magnetic loops are quite well known in the ham world.  It's just that they aren't all that well-used.

This is very odd, because over the past couple of winters, I've been playing with my own homebrew version, and the results are spectacular.  I would also refer you to the WSPR results of my colleague, Ken Franklin G3JKF, who has some of the most carefully-made loops producing amongst the best signals in the EU on several bands.

Thanks to this nice image by M0UKD, you can see how simple, beautiful and practical a magloop really is. Once you start trying to make one, you will realise they are not as demanding or difficult to tune as many make out.

By 'spectacular', I don't mean 'it will beat the pants off a yagi at 120 feet'.  That's just a silly comparison.

But, if you have ever put up a dipole and been a bit disappointed with the performance and noise levels, then the magnetic loop should be next on your 'to do' list.  Note: not on your 'to buy' list!

The reasons I say a magloop is worthwhile are as follows:

• Physically small - about 1.25m per side for a 20m version, which you can also tune to the higher bands with a suitably rated capacitor.  

• Does not need height for proper operation.  A metre or so is enough.

•  Because of the size, is a (perhaps the only) solution in very high wind areas (like mine!)

• Won't be recognised as an antenna by most, giving you far less likelihood of neighbour and planning problems (loops for 20m are generally within planning rules, if you live in such an intolerant area.)

• Magloops can be used very successfully indoors.   Mine gets across the world on 5W WSPR beacon mode, at 0.5m off the kitchen floor.  The difference in signal between a quarter wave vertical with elevated radials out in the wild weather and the loop indoors can be undetectable (WSPR tests.)

• Magloops are essentially immune from household mains and local noise, allowing effective use in proximity to such sources. 

• Built from 22mm copper tube, are very cheap to build for the 20m and higher bands.  Even at 80m, with a perimeter of 15m and made of wide 42mm copper tube, the price is hundreds of dollars lower than a commercial loop.

• Capacitors can be found second hand, homebrewed, or bought.  If you are good with heavy duty soldering and electronics, a comb-type capacitor can be made and the loop tuned by opening and closing the two halves of the loop (which does, admittedly, demand high insulation and construction standards.)  Vacuum capacitors are to be preferred, as they are very reliable and predictable in tuning.

• Performance is often said to be similar to a dipole, but without the height.  I think this is a fair comparison, though allow for much lower noise and QRM levels from the loop.  I find a horizontal dipole is rubbish next to a magloop (or, in fact, much of any other antenna type.)

There's a lot of stuff written about loops that tends to put people off.  Chief amongst these is talk of very high voltages across the tuning capacitor.  This is really silly, because, whilst it is true there is a high voltage present, this is not something that should scare off those comfortable with basic radio and electronics.

The main thing to contend with is very sharp tuning.  So you need good quality, stable and weatherproof means of installing and adjusting your capacitor.

A loop is, purely and simply, a fairly short perimeter of copper tube - make it as wide as resources and the cost-benefit analysis allows- with either a direct feed using various matching legs, or via a Faraday loop, which is an even shorter bit of wire made into a loop and connected to the coax feed.

Somewhere in the loop, usually the top, you must install a capacitor - either a high voltage butterfly air spaced type, or a vacuum type.  Vacuums are available on e-bay from eastern European or Russian sellers regularly, at prices well below $100.  I've never yet had a problem with sellers from those regions.

The only care you need to take is in making very good connections to the loop and capacitor.  A rush job won't do.  Use wide copper braid or heavy duty cable, and don't mix metals by using stainless steel clamps bonded to copper, which can lead to much lowered efficiency.

Having used all sorts of wire antennas, the magloop is the one that stands out as being a very good performer, immune from heavy winds, can be used indoors with little performance reduction, and can be practically scaled with only modest cost impacts to 80m (or lower!)