Friday 29 August 2014

0% Compliance for USB Chargers.

During ongoing discussions within the radio community about EMC issues arising from the flood of Chinese USB chargers, my attention was drawn to this important article.

Given that most of us have several of these damned things around the house, this is certainly worth a read:

http://www.electricalsafetyfirst.org.uk/electrical-professionals/product-safety-unit/plug-in-chargers/

Suprisingly Useful Tip of the Day

The other day, I accidentally soldered a PL259 to the free end of a roll of RG-8X.  This proves to be surprisingly useful, because I'm always chasing a brainwave when I am connecting-up coax, usually a brainwave in bad weather, or when there are other things to do as well!


By making sure I always have a PL259 nicely finished off at the end of the reel, I can just cut the right length needed for the job, connect-up at the antenna, and pass the other end through the wall for some comfortable indoor soldering to finish the job!

Thursday 28 August 2014

SIM 31 Mode

No sooner had you managed to twiddle all your settings than another digital mode arrives!

Yes, folks, SIM-31 is here.



Fair play, it's a good new take on PSK, seemingly much more robust in the face of poor conditions than plain PSK-31.  There aren't many using it as yet, but it's very early days.

What SIM-31 doesn't have is charisma!  Whilst it has a chat mode, its set macro offerings are very 'Spanglish' in nature, and the whole package feels just a bit sterile.

That is pushed even further in that SIM-31 includes a fully automated setting that can initiate and complete a QSO without any operator input whatsoever.  I mused on that type of 'amateur radio' in yesterday's post, and the distinct feeling you get when you see an automated 'CQ' call is one that highlights the pointlessness of 'conversing' with a machine with no human at all on the other end.

I'm not sure if SIM-31 will take off in the community.  For my money, I much prefer the quirky but very robust ROS mode for when conditions are poor (ROS was developed for this purpose.)  Despite the powerful benefits of ROS, very few use it.  I suspect SIM-31 will discover the same ground.

You can download SIM-31 from this site

Wednesday 27 August 2014

Philosophy of Radio

Oh dear!  It's serious when it comes to philosophical matters!

The prompt for this post is the discovery that my FT-450, a lovely acquisition from a famous internet auction site, allows the recording of 10-second messages - typically 'CQ' calls - for later playback.

Now, I've often developed sore throats from calling 'CQ', so this facility is really useful.  But, it does beg the question: if we can automate 'CQ' calls, and automate most of a QSO via the various digital modes, are we as operators simply reduced to button-pressers at the appropriate moments?

The point being that, whilst most modes need us to click a mouse or press a button, that's only from kindness of a sort; it's pretty obvious from modes like WSPR that the whole experience of radio can be fully automated, with no need for an operator, other than being the licence holder for the transmitter, at all.

Now, I love WSPR.  It's a phenomenally useful mode.  It's also fully automated.  You can even exchange valid QSLs based upon it.  So, is full automation a future for radio?  Yes.  But not the full future.  Automation where it's appropriate and useful.

Otherwise, it's clear that real humans love real involvement in the sending and receiving of transmissions, and I see little evidence that what we have today is going to be much different from what we will have tomorrow.  You only need to spend a couple of days on faceless digital modes to realise the truth of this!


Friday 22 August 2014

Ten.

Ten.  That's the global total of operators, including me, that are currently active on 60m WSPR.

Admittedly, I only just came to 60m this week.  But really, only a handful of stations across the globe?

This is a real shame, and rather contrary to the spirit of allowing access to 60m, which is meant to be largely for the purposes of experimentation.  Surely, figuring out the propagation system using the invaluable resource of WSPR is a lynchpin of such work?

Come on, guys and gals!  Get active on WSPR.  If it weren't for the couple of ZS stations active on 60m WSPR, there would be no stations outside the EU. 

This really is a sorry state of affairs, dear ops!

Thursday 21 August 2014

Fitting PL259 Plugs to RG8-X

Like many operators, I'm a regular user of the relatively low-loss RG8-X coax.  It's a lot nicer than using the very bulky, stiff RG-213, which has much the same loss characteristics.

It's always a bit of a question as to how best to connect coax to a plug.  Soldering to the braid through the plug holes is always prone to heat-damaging the inner insulator - damage that you can't assess because it's largely out of sight.

An old, dismantled RG8-X plug to coax connection.  The screw thread provides very good physical and RF coupling.
 
But it's very easy with RG8-X.  First, I use coarse aluminium oxide sandpaper (or a metal file/rotary tool head) to rub away a key to the base metal all the way round the outside of the bit that attaches to the outer sheath of the coax.  I then carefully heat the plug and add a thin layer of solder all the way around.  If you melt a blob of solder onto the tip of the iron and simultaneously let it touch the plug, this is a very good way to quickly transfer heat to the plug.

After the fairly long time it takes the plug to cool down, I strip the coax as usual.  I pull the outer braid back over itself, so that it faces away from the plug.  You can then screw the plug directly onto the braid and PVC sheath, which fits very snugly, without the need for excessive force.  This makes a very stable, secure and sound RF connection with the plug, as you can see from the years-old example recently disconnected.

To make doubly-sure of a good connection, I then wrap the remaining short length of braid around the tube of the PL259 that fits over the braid/sheath, and then apply solder, which attaches itself very easily to the plug due to the earlier pre-soldering.  Once it's cooled, add a layer or two of self-amalgamating tape to add some mechanical strength and weather tightness (if needed.)

You now have a bomb-proof RF connection to the plug!  I'll add some more photos of the process when I get a chance...






When ATU Bypass Isn't Necessarily So.

A long time ago, when I was even more ignorant of ham radio set-ups than today, I tried to create a well-matched delta loop by using an ATU's SWR meter, with the matchbox set on 'bypass'.  I remember trudging backwards and forwards so much in that exercise that I'd worn a very muddy path in the garden!

Beware stray currents - and false SWR readings - on ATU 'bypass'.


I never did achieve a low SWR with the ATU meter, and wondered why that was.  The answer, it seemed, was that, even when switched to 'bypass', there is some kind of interaction between the RF and the ATU circuitry, leading to strange and usually meaningless SWR meter readings. 

This phenomenon made itself known again the other day, when I switched over to an extremely reliable 2-ele quad for 6m that has a 1:1.05 SWR at worst.  It went via a coax switch to the ATU on 'bypass', and then to the rig.  I keyed-up to check the antenna, and the rig SWR meter was reading 1:1.5!  I scratched my head a bit and thought about what had changed recently.

It turned out that the changed item was the position of the inductor switch on the ATU.  I'd been using an inverted-L on 60m, this antenna design necessitating the use of a matchbox.  I turned the switch back to its earlier position, and the problem 'high' SWR on the 6m quad vanished.  I connected to the quad directly via a separate SWR meter, and that also reported the expected, 1:1 SWR.   It was the same with the delta loop; only by using a standalone SWR meter and direct connection to the rig, rather than via an ATU on bypass, was I able to cut the right wire length with ease.

Some ATUs might be OK in this regard.  But seeing as many of us use relatively cheap units by the well-known producers, it's a salutary point to note next time you want to check what your antenna is doing!

Update: Someone pointed out to me that the ATU I was using is only rated up to 30MHz which, they opined, was also true even when set to bypass.  They're doubtless correct in this, but I think most people, perhaps naively, expect 'bypass' to mean 'completely bypass, whatever the frequency', which isn't the case.


Friday 15 August 2014

RSGB Engages a PR Manager

I have to say I was relieved this afternoon to learn from Graham Coomber at the RSGB that the society has employed a PR manager to raise its profile.


Say it loud, say it clear. 

Neither the society nor the hobby of amateur radio is often in the general news.  I've been searching online from time to time for any hint of the hobby, and apart from the odd news item from the US, there really is nothing out there. 

Coomber says the Board have been aware for some time of the need to get better and wider publicity.  Whilst it costs the society money, I think it will prove to be money well spent.  After all, politicians, lobbyists and organisations typically issue several press releases to journalists each and every day, vying for column inches in the papers, online, and on TV news. 

According to Coomber, the society is already learning a lot from the PR manager, who has no previous experience of amateur radio.  Like Coomber, I'm very sure that's a good thing, because years of doing things 'our way' have not been successful by any measure.

Without PR, we are invisible and non-existent to the wider public.  That is a very bad thing indeed, especially as there are plenty of really interesting stories that might change perceptions.

So, well done RSGB Board for seeing the light, and doing something about PR.  Now it's a case of effective deployment.  We're watching...


Thursday 14 August 2014

The Future of Amateur Radio - The 'Youngsters' Debate.

In response to a thought-provoking and well-presented discussion on attracting youngsters to the great hobby of ham radio, I submitted the following response to the RSGB this morning:


Youth Proposals.

I was very impressed with Graham Muchie's missive on how best to revive the hobby, which prompts numerous questions to be asked.

I doubt I would ever have taken an interest in amateur radio were it not for CB in the early and mid-80s.  Now, stop and think about your reaction to the term 'CB'.  In most people, it's negative.  An undisciplined free-for-all using silly and needless jargonese.

Yes, CB was all those things, but only after you had learned how to put up an antenna, select the right coax, use an SWR meter and solder a PL259 plug.  And there you are: the essential basics of knowing how to put an amateur station together.  Whilst we might want it to be more technical and mysterious than that, it really doesn't need to be.  Radio is not, as it used and arguably still is seen by some, a club of exclusivity. 

OK, the fraction of CBers taking more of an interest in the technical side was probably fairly low.  But all of them had to know something about how to 'connect up', and all of them got to realise the benefits and limitations of radio transceivers in the home.  Those going illegal and operating 'linear'-assisted AM CB even saw the benefits of different modes and output powers.  Illegal, but they were learning.

In other words, some seeds of interest were sown amongst a fairly large proportion of the population.  More of those seeds would have germinated had there been no rabid antagonism surrounding whether or not you were Morse-literate, and a protectionist campaign to keep HF to the 'old-timers', aided by the option only of doing the full (and thereafter largely useless) electronic theory course, with no entry level at all.

How do we get kids to climb the amateur radio ladder?  Image: mine.

So, coming back to your suggestions, I would say that a simple, basic licence that focuses on the basic essentials of reasonably disciplined operating and gets youngsters onto 2m or even 6m and upwards should urgently be put in place.  My daughter of eight tried the Foundation Licence, but failed.  Because she hadn't learned?  No, because the exam wording, for a kid, was too convoluted for her to grasp what she was being asked about.   When I asked her the questions in a simple way, she would invariably know the answers.

As to demonstrating, I think this will always tend to attract people who want to show off what they, rather than someone else new to the hobby can do.  You nod at this in your article, and rightly so.  Only a selected group of people operating a well-aimed outreach campaign in large county shows, exhibitions and so on, who are known to be capable educators and motivators, can succeed with demonstrations.  The bloke who sits at home on 40m talking to his ageing mates up the road isn't going to cut it - and hasn't!

Let's combine the two foregoing and say that we need a much more simple first licence that abandons the dated approach and terminology of testing, where we can show youngsters that very high frequency doesn't mean very limited frequencies.  Do they know that two £35, 5W Chinese FM handies and two stick-and-wire quads can get them talking through a satellite every 90 minutes?  Do they know that they can bounce signals off shooting stars?  Do they know they can work the network of repeaters across the UK, and access distant ones with just 2W?  There is plenty more that they can do that not even I know about.


Much maligned by hams, but CB gave the radio bug to many in the 80s and 90s.
 
I don't think that kids entering the hobby, or even many already within it, want to focus on building transceivers, and I don't think this is the best thing to include in a basic licence syllabus.  How many of the total ham population really do build a transceiver?  I guess very few.  It should be part of the wider, career-long learning of an operator, but I think the debate about homebrew transceivers is really just an indication of the age of those involved in the debate, rather than what youngsters want to get involved in. 

And finally, moving on from that last point, I wonder what place in all this debate a proper understanding of what real young people feel about radio, and what takes their interest?  There is a certain feeling that it's middle-aged radio operators musing about what they found interesting as youngsters, not what today's youngsters find interesting.  Has the RSGB commissioned a proper, scientific survey?  It may wish to consider doing so.

Tuesday 12 August 2014

Meteor Scatter on 6m.

For a long time, I've been trying to get some sense on how best to operate on 6m meteor scatter.

Of course, if you've just a wee bit of experience, MS is easy-peasy.

Plenty of pinging opportunity - if you can get some help to start off with!  Image: Wikicommons/Edmund Weiß

And there's the rub: I've not operated MS before, so which frequency?  Nobody seems to want to agree, with essentially all online resources being US-based.  In the EU, things are different, so I had to keep looking; 'PingJockey' is no good for me! 

I asked a few operators, who seemed to want to keep the MS activity to themselves by not recommending any frequency or mode.  The sole helpful and relatively up-to-date site I came across was this one by G0ISW - big thanks to him!  This site also pointed me to the EU-centric MS forum site maintained by ON4KST - again, big thanks are due there.

And which mode is best?  JT6M is ubiquitous in online resources.  This is not the latest MS mode, WSJT9 not even offering it as an option (it has reappeared in WSJT10 beta.)

The band plan for Region 1 is meant to have nudged MS operations from around 50.230 to 50.320, but operators seem to have other ideas, with only a very few having moved as IARU wishes.

Listening in at 50.230 just ahead of the Perseids, I could hear plenty of signals but no decodes.  This was my failing to appreciate just how stuck to JT6M everybody seems to be.  You have ISCAT A and B, JTMS, FSK441 but, no, all activity seems to be JT6M-based.  Then I got the decodes.

I'll see what the prospects of making some QSOs with a simple 2 ele quad and about 35W during the narrow peak of the Perseids might be later today.  For now, I'm glad I cut through all the dated and/or wrong internet advice, and once more, found out for myself, rather than through any help from experienced operators, how to cut it on 6m MS.

UPDATE:

A few hours after writing this, a lunchtime session produced my first MS contact with SP7QJF at a distance of 1147 miles (1847km) - not bad at all, and approaching the maximum expected distance for a MS QSO, given the simple antenna and low power of 35W out.  Later, I managed to bag three more QSOs.  It's a propagation mode that needs patience, but you can do it with simple equipment, at least on 6m. 

Friday 8 August 2014

Back to Basics: Global DX from the kitchen.

It's time this blog got back to its roots and promoted cheap, uncomplicated amateur radio.

Not for the first time, I'm going to extol the virtues of a magnetic loop antenna.  These are, to put it mildly, superb antennas that anyone can make for pocket money.

What do you need?  A basic loop covering at least the 30 and 20m bands, the mainstay of DX operations you might say, is just 1.2m on a side.  With increasingly sharp tuning and lower efficiency, it is here, and ought to be elsewhere, tunable down to 80m.  On a single wooden prop to lift the loop about 0.8m off the floor, this is still small enough to comfortably fit through a doorway, and can be stored behind a wardrobe.

So, 15mm or, better, 22mm copper pipe.  You need 4 x 1.2m altogether, plus four 90 degree 'elbow' bends, either presoldered or unsoldered, and some plumber's solder and flux; make sure you clean the joints with wire wool to immaculate dry shines, or they won't solder properly!  You can even use compression fittings, especially if going portable, such that the loop can be disassembled.  The primary (small) loop to which you connect the coax can be made from thick electrical wire or microbore copper tube.

A trick with the primary loop is to make it an oval, rather than a circle.  It also helps matching considerably if you allow some of the loop to hang across and slightly below the lower part of the secondary loop.  A lot of loop experts have noted this.

The only other thing you need to scavenge for is a decent wide spaced capacitor with a value of 0-200pf as a starting point.  You can use vacuum caps, but these are a little expensive and very heavy, really only usable for permanent loops.  They are also much harder to tune remotely, needing relatively high-torque motors.  An air-spaced cap is easily rotated with a cheap low-torque, low speed motor, or just by hand and ear; a magloop has very sharp tuning, so it's pretty obvious to the ear when you've hit the sweet spot.

An hour or so of 20m WSPRing at 5W into a kitchen-based magloop.  Note the three VKs hearing me!


But does such an unlikely - and very small - antenna actually work?  It absolutely does!  At 14MHz, the magloop just described is about 86% efficient, or about 1dB down on a 100% efficient antenna.  In other words, it's bloody efficient!  This is confirmed when running on the WSPR beacon mode, which shows a 5W input easily traversing all corners of the globe.  Switch to JT65 or similar, and you're QSOing with the best of them!

So, if you live in an apartment, or have no garden, or are wondering which antenna to buy, think seriously about a magloop.  So long as you get the right capacitor (check regularly on ebay), then building one is easy.  You can sometimes get a cap for a few pennies, but they are often much sought-after!  Soldering doesn't need to be perfect, nor does the whole thing need to look pretty.  

So, go build a magloop today! This site will help with the numbers.



A Tale of Two Societies

Every month or so, a colourful, interesting and inspiring society magazine arrives through our letterbox.

Another society magazine - RadCom - also arrives with the same frequency, but isn't a tenth as engaging.

Bill Nye (left) of the Planetary Society, enjoying very successful lobbying in the White House.  What chance this type of influence at the RSGB?


The former society - the Planetary Society - is typically American.  If we tend to think that Americans are too noisy, too enthusiastic, too anything, well, they are certainly good at running societies.

Imagine the RSGB sending a full-time CEO to live in London for part of the year so that he/she could spend as much time lobbying politicians in favour of the society as possible.  It's inconceivable under the present regime.  Yet, that is precisely what the CEO of the Planetary Society is doing, taking an apartment near Capitol Hill - and it's bringing results.

Just like the RSGB, the PS was seeing dwindling membership numbers.  Yet, it has turned the ship around and, for the first time in 10 years, has recently seen memberships increase.

Ed Vaizey was our man of influence at the NRC opening.  He passingly mocked the RSGB for its old-aged male membership, but the comment passed over the heads of attendees, who laughed approvingly!


The RGSB can't even get its priorities straight.   Hit their web homepage, and there's not a word about 'joining us' (which is buried on other pages).  It ought to be the number one most important option on the web page.  Instead, GB2RS 'news' gets the top spot.

Things have improved, but the whole caboodle still smacks of middle-aged restraint.  There is nothing exciting shouted about.  It seems it's all too middle-classed and stiff-upper-lipped for that. 

Above all, the RSGB ought to take note that the Planetary Society now sees twice as many people joining via the web than all other means combined.  

It's time the RSGB took a radical and honest look at itself.  It's no good saying the bad old days have now gone, and money owed by a big-wig recovered.  We have seen promises of turning the society around, but instead, now several years down the line, it simply seems to be sinking.

Take a look at the Planetary Society, which costs just £22 a year to join, and see how the RSGB could learn - a lot - from how it does things.


Wednesday 6 August 2014

Kevlar Antenna Wire: As Good as It Seems?

My first contact with Kevlar-reinforced antenna wire came when I bought one of Geoff Brown's (G-Whip) end-fed units many years ago, where it was said to be "essentially indestructible."

Kevlar-cored wire.  Light and strong, but not indestructible.


For sure, this wire is tough.  You can pull away at it with pliers, probably have a good go at pulling a car with it (not recommended, of course!) and it is relatively easy to work with.  It has a good resistance to forming tangled messes of wire, a definite consideration for any portable working!

Most of all, Kevlar is lightweight - up to three times lighter than PVC-covered Flexweave.  That's a major consideration when you want to prop up an antenna with a fairly simple fishing pole, none of which can carry very much weight.

Using Kevlar wire is a little fiddly in that you have to first strip away the outer plastic as normal, which leaves you with a densely wound layer of very thin copper strands that is much the same as a coax outer braid, and then the Kevlar core fibres.  The fiddly bit is that to solder the wire, you have to pull back the braid, and then cut the Kevlar fibres just ahead of the braid with some very sharp scissors; blunt ones will just make a mess of the wire and fail to cut the tough material.  This leaves a short length of solderable wire with no Kevlar in the way.

Sometimes, the braid gets mixed up with the Kevlar core, which usually means you have to cut that bit off and start again.  The problem with the Kevlar being in the way of any soldering is that it absorbs heat and contaminates the joint to be made, such that you end up with a stubbornly unsolderable joint.

You can of course rely on just compression of the wire to a spade connector or such like, where removing the Kevlar core isn't necessary.  But I always prefer to have some degree of soldering.

Make some strain-relieving loops at connection points.  If you cut a backwards slot in dipole centres and insulators, you make removing and replacing wire infinitely quicker and simpler!

Don't rely on a belief that this wire, often marketed as ''mil-spec" is immune from failure, though.  I've had a delta loop up for four years or so, and after that time, there have been a couple of failures of the conducting braid, generally at corners where there is higher stress.  Some of the strands appear to fail from metal fatigue, which slowly deteriorates to the point of an unstable SWR due to an intermittent continuity.  Arcing is evident in all the failures, which slowly burns away the Kevlar, too.

A badly failed corner of a delta loop, where arcing has burned the strengthening Kevlar core away.  In fairness, it took more than four years and countless gales of wind to reach this point.


So, if you're mounting some wire, make sure you incorporate a couple of loops at the end of the wire that connect to insulators or dipole centres.  This leaves a tail that you then connect to the transmission line, but isn't subject to most of the strain put on the rest of the wire.  If you don't do this, even a Kevlar wire will very soon fail at the point of joining to a spade connector or similar.

To conclude, then, Kevlar is worth buying because of the considerable weight saving and, if you are blighted by heavy winds, less wind-catch area.  In terms of its physical durability, whilst it is very strong, it isn't at all immune from failure.  Properly installed, stress-relieved Flexweave or even drawn copper is likely to last just as long, if not longer, provided you can accommodate the extra weight and/or stiffness of those wire types.





Friday 1 August 2014

From $4999 Per Year*

*PLEASE NOTE: Since this article was first published during 2014, annual rates for Remote Ham Radio have reduced significantly, with pay-as-you-go rates also changing.  Latest pricing here.

At a guess, you're probably scratching your head about the topic of this post.

Well, $4999 per annum is what Remote Ham Radio are asking for their first level of 'PremiumDX' membership, which has limited numbers according to their web site (1/8/2014), to a fully-equipped and very capable ham radio station.

Vision of the future?  (Not a depiction of Remote Ham Radio's products)


There is no doubt at all that what RHR is offering is top-end stuff, giving hams the chance to remotely operate a world-class station on any of the HF bands, including full four squares down to 160m.  Very few of us have room and/or weather conditions suitable for installing one of those!

But $4999 per year?  That's a LOT of money.  The top tier comes in at $9999 per year - a hefty fraction of an average annual wage.  [UPDATE: Basic membership is now just $99 per year, plus per minute usage fees, currently (Sept. 2015) $0.49]

RHR also offers a lower price point of just 15 cents per minute on a 'pay-as-you-go' type of scheme - but it does have a modest $99 one-off set-up fee.  No doubt that would be more than worth subscribing to, remembering that the bills, like internet broadband of old, will inevitably soon mount up.

Questions about the 'feel' and 'authenticity' of this kind of ham radio are bound to resurface.  I've never operated remotely, nor would I particularly want to on anything other than a 'let's see' basis.  [Update: At $99 per year, I am tempted to experiment.  But the $0.49 per minute usage fee could lead to very big bills indeed!] 

Even though RHR say operators can use "their own callsign" when using their remote stations, it would appear that to operate in accordance with law, we would all need to be W2/Something (for example), which is a bit odd and perhaps less-than-ideal from a DX entity-chasing perspective, at least for the person using, rather than contacting the remote station.  You can read a good review of the recent legal and DXCC position in relation to TF4M here.

I now see RHR seem to suggest that operators use a station callsign, in that their transmission sites have their own callsigns, which you use.  In their own words (Sept. 2015): "Its [sic] important to remember that the other station does NOT care where you are sitting, they only care where the TRANSMITTER is."  Which means that a moderately interesting station like mine in MW land becomes one of tens of thousands of east-coast US stations that holds very little interest at all to the rest of the world.

More concerning to me is the vision of amateur radio that's being pushed: limited membership, very high prices.  This, despite the fact that the rich and retired are a dying breed, likely to last no more than another 20-odd years before the much poorer victims of the Great Financial Crash replace them. 

I personally wish Remote Ham Radio well with their venture; it is a significant investment in a complex hardware and software service that carries risk, but I'm sure will be popular.

But I also hope they and others will try to point out to newcomers and the poor alike that ham radio doesn't need to cost 15c per minute, nor $99 per year (plus steep usage fees).  It can be a lot cheaper than any of this, and a lot more rewarding too.