Saturday 30 April 2016

Poor DAB Digital Radio Signal - Fixed!

Over the past weeks, DAB digital radio here in the UK has been updating its list of channels, requiring a re-tune to update radio receivers.

I did this easily enough, although I am no fan of DAB, given its 'all or nothing' reception characteristics and, if many stories are to be believed, the increasing trend towards mono-only broadcasting.  Some stations have stopped broadcasting nationally owing to the high cost of the system.

But once I had retuned, I found the signal was very poor to the extent that I couldn't listen to most of those I'd been listening to for a couple of years.

So, out came some wire to try and build a simple external antenna.  This was easy for a ham radio operator to accomplish, but I found it didn't work! 

On disconnecting the external antenna to investigate, I found all the stations were now at good strength, with no digital dropouts.  The problem seems to have been a poor contact between the shield of the receiver antenna input and a strip of metal - effectively the missing half or ground of the rear whip antenna, taped to the back of the inside of the casing.  On undoing the screws and then doing them back up during work on the antenna, I'd tightened-up the contact between the shield and strip, restoring normality!

So, do check the innards of your DAB digital radio if you find poor signals all of a sudden!

Friday 29 April 2016

Why Aren't the Communicators Communicating?

A couple of years ago, in the face of tough times ahead, the RSGB appointed a Communications Manager - Heather Parsons.  In essence, as it was portrayed to me by Graham Coomber at the time, this title meant 'PR person'.

I was happy to see that development, because a search online at the time revealed precisely zero news items about amateur radio on the internet - and the same number in the mainstream media.

Now, in 2016, I've repeated the exercise, and listened to Ms. Parsons give an interview on the DX Coffee website, back in later 2015.

And guess what?  No news items about amateur radio are to be seen, even now!  If it wasn't for the Southgate ARC, there wouldn't be much of anything at all about ham radio on the internet.  I've seen one - actually quite good news item on the BBC, possibly just prior to Ms. Parsons' appointment, and seemingly the product of a single club's efforts, rather than the RSGB itself.  And then - nothing.

Ms. Parsons notably makes no reference to PR in the mainstream media when she gave her interview.  Whilst she mentions the attempts to engage "the youth" through some snazzy online videos that really don't impress me much, everything else seems to smack mostly of internal communications.

I'm sure Ms. Parsons has her work cut out, trying to drag the RSGB into the 20th, let alone the 21st century.  I'm beginning to think she isn't being given the right directions by the Board or, worse, is being throttled by them.

So far, the RSGB continues to look from the outside as an organisation that really hasn't turned itself into anything remotely appealing. 

Looking again at their 2013 survey (a new set of results is due in 2016), you can see why the RSGB should be worried: those in the 40-55 age range are far more likely not to join the RSGB than any other group.

Those older than this clearly just become tired and lazy, never bothering to cancel their subscription because it comes to be seen as something they 'have always done'.  The younger ones are simply voting with their still-active minds and feet, and seeing the society for what it is or, rather, what it isn't.

Many continue to label the RSGB as "elitist" when I talk to them.  To be honest, I can see their point, not least because RadCom is so different to the ARRL's QST QST is engaging and full of articles that assume you know nothing about the topic being featured - and then provides you with some education.  RadCom, on the other hand, invariably features some ludicrously niche project requiring advanced skills that often seem to - and indeed do - originate from those who have reached a great age, and lost contact with components smaller than a brick.  I've a lot more faith in QST product reviews than those appearing in RadCom, too!

OK, there is now the 'Basics' and additional, more technical magazine.  But I'm not sure this is going to make any changes to the membership.  What the RSGB really needs is something of interest on newsstands - which RadCom isn't.  There's no point shouting into an empty room that your hobby is really interesting.  Yet, in essence, that's what the RSGB keeps doing.   That's why its membership is marching towards a cliff edge.

So, I will keep on monitoring to see whether or not the RSGB will ever start to send out press releases to the papers and the broadcasters - and that the happy message about ham radio ever makes it to those who might be interested.

For sure, it will be interesting to see the outcome of the 2015/16 survey...


Thursday 28 April 2016

E-QSL: Paying for FT4JA

Processing QSL cards and e-cards is a real chore, I find.  Not only that, dealing with physical cards can quickly become ruinously expensive.

What I get for my $1

Some time ago, I decided that I didn't need a physical card, although I'm perfectly happy to receive them, and always interested to see where they're from. 

But I had to get tough on those apt to send a card on a whim.  Being very active on the air, it was becoming unsustainable for me to be charitable by returning cards several times a week.  The postage costs are far too high for this kind of thing, so I had to reluctantly impose a $2 charge, which is an at-cost affair.

This imposition has seen the number of cards dropping through my letterbox to just one or two a week.

Today, I was confirming a large number of E-QSLs when I came across FT4JA's e-card.  It had a nice little exclamation mark on a yellow triangular background, indicating something had to be done.

That thing was payment!  Well, it was only 1 USD, and the dxpedition probably cost a lot of money.  So I did, more as a 'look-see', pay for this card.

I understand entirely why the transaction is in USD.  But for those, perhaps the majority of folk who do not have a USD account because they are not Americans, there is usually a charge, sometimes with a minimum amount, that adds to this superficially small amount.  At least the transaction worked smoothly.

The other thing is that charging for E-QSLs does rather go against the grain of ham radio.  Yes, I am doing the same thing for the same reason with physical cards - I don't want others' cards very much, anymore than the FT4JA want tens of thousands of others' cards.  

It's just that physical cards cost money to make and send, whereas with purely electronic qsling, it's difficult to see where the costs are incurred.  FT4JA clearly were logging as they went, which is why I received their E-QSL first.  So the only answer in this case is that it's money-making, however justified or necessary.

Yes, I guess I would pay $1 for some other rare DX.  But I hope this charging for E-QSLs doesn't catch on too much, because it would certainly push me over the edge into abandoning E-QSL altogether.  I'm already pretty close, choosing these days to update my LoTW account daily.

Or maybe I should be more entrepreneurial, in charging everybody $1 for my E-QSL, because Wales stations aren't so common, and everybody seems desperate to add MW to their DXCC counts.  I could be pretty rich in no time...



Saturday 23 April 2016

Comudipole

Over the past weeks, I've been busy, on and off, helping get a new licensee up and running on all bands, and pretty much all modes, from 80m to 70cm.

The HF side is always difficult to settle upon in terms of antenna choice.  But, for all-round performance, relatively modest space requirements, very low visual impact, and extreme wind tolerance, a simple wire dipole is hard to beat.  It's also cheap: even if you buy a balun, the antenna only cost about £55 or so.

I recommended my friend use the Comudipole - or doublet - arrangement, which is very easy to set up.  Another ham had earlier made up a coax-fed dipole of galvanised steel wire for him, but the losses for a non-resonant, multiband dipole like this are unacceptably high for coaxial feeding.

Simply by dumping the coax and replacing it with 300 Ohm twin fed to a 4:1 current balun (for speed, we bought a G-Whip commercial unit, but it's easy to make your own), the dipole can be used with inconsequential losses.

I'm not a big fan of steel wire, but it does seem to work pretty well, and has an advantage in that one can really rack-up the tension on it to avoid sagging.  All the same, I'd always choose a non-magnetic, copper wire for my own work.

I was very happy to see that the comudipole matches up with my friend's internal ATU on his FT-450D with no problem at all on all bands from 80m to 6m.

Here is what the SARK-110 antenna analyser makes of it in a full HF sweep:

The 80-10m Comudipole HF sweep. It also matches nicely on 6m.


Some of those SWR values might look awful to the uninitiated.  But, remember that SWR is, of itself, a lossless phenomenon, and that the losses in the 300 Ohm twin are only a fraction of a decibel - much lower than the same antenna fed with coax.

I'm glad to say the practical experience of using the comudipole is very good, and my friend is very happy with the speed and efficiency with which he has come to be on the air.  I'm glad I chose this antenna for him, and relieved it all came together with no problems!


Wednesday 20 April 2016

Crossing the Atlantic on 2m

This (May 2016's) QST features a really interesting article about an attempt in 2014 to get a 2m 'first' by getting a signal across the Atlantic from Newfoundland to Europe.

The set-up was quite heavy-end: a 43-element ladder Yagi of horizontal polarisation with a claimed ERP of about 150kW from a 750W input (I make it more like 182kW.)

A 40-something element 2m ladder Yagi isn't beyond modest means, but it's a little bit of effort - and perhaps not ideally polarised.


Even with that power level, and some persistent working by the intrepid team, they failed to bag the Brendan Prize, because the brief signal they did manage to get across the Pond was due to reflections from the ISS.

That ought to be the subject of a prize in itself!

Resting on the shoulders of giants like the Newfoundland team, I set to thinking about ways in which the chances of success might be improved.

The one obvious way to increase the chances of anything happening is to make an attempt more often.  Operating at the power levels they were, and effectively out on a field trip, the team had only a narrow period during which they made the attempt.  So, someone sitting at home in the same location, perhaps with much more modest equipment but, crucially, able to try every day, might well succeed - eventually.

The other problem I identified was the timing of the attempt.   Es is loosely associated with other summer phenomena such as Polar Mesospheric Summer Echoes and noctilucent cloud.  All these phenomena are strongly influenced and modulated by atmospheric gravity waves.

So, from an analysis of Es statistics at VHF, and from knowledge of seasonal changes in the upper atmosphere, the Newfoundland team, in operating during the first days of July, had already reduced their chances of success.  That's because the phenomena that could help them get their signal across the Pond reach a very strong, sharp peak in mid-June.  The upper atmosphere is exquisitely sensitive to changes brought about by the progress of the Earth's orbit, and it would be a mistake, perhaps as the Newfoundland team might have done, to dismiss a couple of weeks as unimportant to the chances of success in this difficult endeavour.

Then I turned to the gain of the antennas in use.  I can't model a 43-element Yagi in the ARRL HF Terrain Assessment software, but I can compare equivalent 8-element Yagis, relative to their differing terrain profiles.

For Newfoundland, a near-clifftop location makes modelling easy - a fairly sharp drop to the ocean from about 60 feet or so.  I also modelled by own chances by using my existing terrain profile out towards North America.  I know that at least 7dBi is available to add to the antenna's own gain from my terrain.

This is the result for the 8-element Yagis, remembering that the Newfoundland team calculated a gain of 26dBi for their 43-element ladder Yagi:

Blue: my ground gain (8-ele at 145MHz), against Newfoundland (red), also 8 ele.


Interestingly, the 8 element Yagi comes in at 23dBi, 3dB lower than the 43-element ladder Yagi.  So the feeling that more frequent attempts through the season might bring a success, even with a much more common-or-garden antenna, might well be reinforced by this result.

This is even more the case when you look at the gain at very low angles, up to about 2.5 degrees above the horizon.  There is a very big gain difference of about 8dB that has to be made up in Newfoundland, compared to my location, at those very low angles.  Even then, it's not clear that a bigger antenna would actually result in significantly more gain at those angles.  Unfortunately, I can't test it out due to the software's limitations.

But it does seem that a somewhat bigger Yagi, and especially if it were vertically polarised, and located at my QTH, might in fact have a pretty good chance of success in getting a signal across the Pond on 2m. I'm now thinking about a 20-odd element Bruce Array, which is very easy and cheap to make, especially at VHF.  A much shorter version on 6m that I built some years ago proved to be extremely effective.

It's so encouraging, I think I might well try it.  I'll be able to try regularly with no more effort that switching the rig on.  OK, I don't have 750W to pump into the antenna, but the old addage of 'if the propagation's running, the signal will make it, regardless of power', remains largely true.  Even so, running about 40W into a commercially-available 22-element Yagi still yields a respectable 1.7kW, which I'm pretty sure is overkill for the task in hand, conditions allowing.

So, with HF being pretty dead these days, the summer HF lull about to enter full swing, and plenty of sunshine, what better project than getting a huge 2m wire antenna made-up and having a go with the JT modes?  The more of us who try, the more the chance someone will get just the right conditions - provided it's not another ISS bounce!




Sunday 10 April 2016

K1ZZ - Parting Shot

David Sumner, K1ZZ and the ARRL's outgoing President, has issued his valedictory article in this (May 2016's) QST magazine.

I was really very glad indeed to see that David has the honesty to confront - and challenge - members about the elephant in the room of amateur radio - old age.

Hardly a spring chicken himself, K1ZZ nevertheless recognises an ageing ham population is bad news.  Image: ARRL.

This is a problem that is certainly recognised by most ham societies across at least the western world.  The RSGB, though, has written to me on more than one occasion, asserting that the reason there is a severe age skew is not because there are no youngsters taking an interest, but that the older age groups represent the stage in life when one takes an interest in ham radio.

This could be reassuring, were it not for the certain knowledge that the post-WW2 'Baby Boomers' are reaching the end of their lives.  Birth rates have declined considerably during these folk's tenure on the planet.

This could indicate a problem for ham radio, because it's from 40 years on that people start to take an interest.  Now it looks as though there will be far fewer of them in coming decades, despite a slight increase in the naughties birth rate - something that will probably have been cut back to size by the very poor economic conditions since 2008/9 that also look set to continue for many years yet.

So it seems, to quote one frank and rare admission by the RSGB in 2013, that, over each ten year period, the age profile of ham radio in the UK gets older by ten years.  So the later view taken by the RSGB - that the age skew is simply indicative of 'boring middle age man syndrome', is entirely contradicted by that admission that the age profile is getting ever-more skewed. 

K1ZZ, then, is absolutely right to make the ageing profile of amateur radio the topic of his valedictory text.  After all, if we are failing to attract members from younger age groups, it may well be that the decline in participants seen over the past few years will continue on a slow but certain slide.  Even in the best situation, where older men continue to take up the hobby as they reach that stage in life, there will certainly be fewer of them.

Whilst I can't verify the accuracy of Google's search trends site, the number of people searching online for ham-related terms like 'ham radio' has been on a steep slide over the past decade - it's down to just a quarter of the monthly search enquiry volumes of ten years ago.  One does have to use that data with great caution, but it might add concern to the argument.

Other factors I see as very problematic for ham radio in the coming years are:

(1) fewer people in the professional electronics/broadcasting industries that foster a 'busman's holiday' interest in ham radio.

(2) as a result of (1), fewer kids, friends and relatives are exposed to the concept and practice of radio.

(3) radio is no longer a primary means of receiving information about the outside world.  It was very important to me, just 35 years ago.  Kids no longer pick up a SW receiver to play with in bed.  Most radios on sale aren't even SW-capable.  Digital radio is making this worse.

(4) consumer electronics are demanding increasing amounts of time, relegting ham radio to irrelevance.

(5) computer-based commnication may lead to less confidence in 'real' conversational skills - witness the few who want to engage in a ragchew these days.

(6) societies that are dominated by older folk, leading to a dangerous disconnection with younger people's interests.  Arguably, this is already happening.