Monday 27 April 2015

Nepal Emcomms: Misguided? (Updated)

The earthquake in Nepal last week has prompted an unusually strong emergency communications response from some in the ham community.

On 20m, a bunch of folk have been trying to keep 14.210 and then 14.205 clear in case someone in Nepal might want some help.

Excitable US operators think they can make a difference.


Now, providing such cover has always been a part of radio.  Indeed, it was a welsh amateur working in a tiny wooden shed that first heard Titanic's distress signals in the UK - which was ignored as rubbish by the authorities for a while.  Not that it mattered, because Artie Moore, the ham involved, could do nothing - nor could the authorities. Ships more local to the event, with radios, could help.

But, one has to wonder about the way in which the current response is being run.  Firstly, whilst there is no 'approved' emergency frequency, the IARU emcomms centre of activity resides at 14.300MHz.  Now, up here, you will generally only hear the Maritime Net during the (UK) evenings.  It's a largely unused section of the band, with only Germans seeming to use above this frequency.

So, it seems very odd indeed that the current Nepal response has chosen smack-bang in the middle of the busiest, most QRM-infested portion of 20m for their operations.  This is evident in the fact that all their efforts thus far seem to be trying to keep the frequency clear, and not actually responding to any calls.

Update: by now, there are sentinels keeping several kHz clear either side of 205.  To be frank, this has become ridiculous.

Indeed, they don't seem to be getting any calls.  That isn't surprising, because the number of Nepalese stations on air during the year can be counted on a couple of fingers during non-emergency periods.  And those seem both to be either businessmen, missionaries of some sort, or DXpeditions.

So, quite why we might expect all this fuss for a region where amateur radio is extraordinarily rare is a bit of a mystery.  This isn't covering a tornado event in the US, where technology is fairly robust and ubiquitous.  It is covering a very remote, less developed area where complex electronics are not anywhere as common.

I do accept that, even if all this effort led only to one person's situation being improved, it's worthwhile.  So much the better if it improves more people's situations.

It has to be said that, listening a bit to the exchanges, it all does sound totally overblown, misguided in where it has set up shop, and seems to be keeping those who like to wear 'Emcomm' hats and T-shirts happy, more that actually helping anyone.  Remember that, in the poorer, developing world where, as any look-up of the WSPR or DX maps will show, amateur radio is practically non-existent. 

That said, the US approach does seem to believe that operators within or local to Nepal can't help themselves via the medium of radio, which is either patronising or naive, or both.

I am sure some will find this contentious, in which case, I am happy to be proven wrong later, when the current excitement is turned into cold, hard facts (and not angry assertions) about (a) how many people in genuine need of help in the affected regions actually called in to the US and (b) how many of those calling had their situation improved directly as a result of the US-based emcomms activity.

We might also wonder whether, without the benefit of the internet to tell them that 14.210/05 was in use for this purpose, they spent some time and maybe wasting valuable battery power nearer the published emcomms centre of activity, perhaps calling in vain for attention.

I fear that, for the most part, emcomms is a nice aspiration, but in practice, does not have the prominence or utility that is often ascribed to it.  Certainly, the current efforts need to be looked at as to who, exactly, it is trying to serve.

UPDATE: At long last, those running the Nepal emergency comms have shifted to where they ought to have been in the first place.  After starting to take up more and more space right in the middle of the band, they seem to have realised the error of their ways and observed IARU recommended bandplan frequencies.


Saturday 25 April 2015

Slimjim 70cm

This week's interest has been branching out into more 2m and 70cm work.  During a rain afternoon, I decided to recycle a lot of old bits of copper pipe into a weather-resistant 70cm slimjim.

The only problem with a 70cm slimjim is that the 90 degree elbows for standard plumbing are large in comparison to the antenna's dimensions.  However, the gap between elements is not important, so I used them anyway, with the shortest possible piece of copper pipe to complete the bend.

Slimjim for 70cm.

Anyhow, the upshot is that, thanks to this great site, I was able to just apply the calculated measurements to yield a perfectly-matched 70cm slimjim in no time at all.  The gap between elements is about 50mm, showing that this distance, unlike all the others, really isn't critical at all - the calculated value was only 16mm!

The fitting of end caps to the pipes presents two problems.  First, the gap is only 6mm, and end caps add a couple of mm each.  This makes the measurements all that much more difficult, and so it's best - as I did - to simply fill them with silicone sealant or similarly easy-to-work mastic.  Second, fitting end caps seals the pipework, so with the application of heat, you end up getting air expansion and bubbling of the solder.  You can drill a small hole in the bottom of the antenna, but it's easier just not to fit the end caps at all!

On just under 2 Watts, and so far only on a low test stand, the antenna allows the local 70cm repeater to be worked reliably, even though it is somewhat hidden behind a nearby low hill. I was amazed to find later that 5W is reliably opening both of the 70cm repeaters so far tested on the Isle of Man - that's 61 miles - and that I could hold a perfectly good QSO as well (thanks to the repeater keeper, GD4HOZ (/M), for that one!)

Now it's a case of figuring out where I get £1000 to finally put together a decent satellite-working VHF/UHF station; so far, I've had to go outside with beams for this - very successful, but rather uncomfortable!

Thursday 23 April 2015

Azimuthal Maps (Free!)

Drifting through QRZNOW's Facebook page this morning, I came across this rather useful site, courtesy NS6T, that prints azimuthal maps to many different paper scales.

You just enter your Maidenhead locator grid, and off you go!

Example azimuth map by NS6T

 
No matter how good your mental picture of the spherical Earth, it's always surprising how that model is sometimes shattered by looking at an azimuthal map!


Monday 20 April 2015

2m Squalo - Gamma Match Surprises!

For a long time, I've had a half-finished 2m squalo sitting in the cupboard.  Having made a perfectly good SlimJim instead, it never really had much of a future here.

Motivated by some warm weather, I decided this week to finish what I'd started, and compare matching systems as I went.

I built two loops exactly the same size, as detailed in the International Antenna Collection.

Loop one had the specified gamma match, with RG213 inner and insulator running inside some microbore copper tube.

Loser: loop number one - Squalo with gamma capacitor matching.


Loop two had direct connection from the inner to one side of the loop.  I didn't include any form of capacitor (at the input.)

Winner: loop number two - Squalo with no (gamma) capacitor matching.  For the best SWR, the matching point of the gamma rod was slightly higher, and the capacitance wire at the top was moved to actually lie slightly within the central cavity of the facing tube.

Both loops could have their ends adjusted by means of thick copper wire soldered at each end (one end in the case of loop 2.)

Which one worked best?

Loop 1, the capacitor version, proved to have a high SWR after I took an analyser to it.  This is probably down to the gamma match connection point being too high up.  Loop 2, the non-capacitor version, came it at a perfect 1.06 at an extremely good 52 Ohm match at 145.5MHz.  This is how my SARK-110 analyser saw loop 2:

Great match for loop 2 (direct coupled gamma match)

Loop one was able to open GB3GD-Rat about 70km on the Isle of Man, running 5W from a hand held.  It could not open GB3GO-R, only about 30km on the Great Orme.  This was very surprising.  The access to the Isle of Man is aided by lots of ground gain, but both repeaters are line-of-sight to my QTH.

Loop two easily opened both repeaters, and I even had a perfectly comfortable QSO with a /M station using just 5W again.

So, the clear winner of the 'Squalo Shootout' is loop number two - the one without a capacitor.  Interestingly, the direct connection is also the method I use with my 40-10m three element magnetic loop, which has proven to be very successful.

Whilst this could be an OK antenna for base use, it has more use as a handy and very compact /P or /M antenna that can hang around in the boot somewhere.  I've a collapsible timber stand to stick it on, so no doubt I'll be getting more strange looks from people passing me, come this summer!

Any technical insights, as always, welcome!


Sunday 19 April 2015

WSPR DXCC: Strange Arguments

WSPR is, at its root, a beacon-type mode that, for some, is an entirely automated, unsupervised system of gathering information on propagation.

This can extend to path propagation studies, antenna performance assessments, and just a simple 'where's my tiny signal going to?' fascination.

Is there any real, valid reason why 2-way WSPR contacts aren't actually contacts?  I don't think so.


I think WSPR is great.  It instantly made all those decades of arguments about antenna performance, using little more than ear-assessed guesswork, look very dated indeed.

But one question that keeps coming up is: should 2-way WSPR contacts qualify as QSOs, and thus for awards?

To my mind - and I have no real interest in awards - the answer ought to be a resounding 'yes!'

The argument against is that WSPR is, to a greater or lesser degree, entirely automated.  That is perfectly true.  But, does the fact of automation make a 2-way contact any less valid than, say, JT65, where the human involvement is reduced to simply clicking on the appropriate responses?

Clearly, it does not.  JT65 could be just as easily made to be as fully automatic as WSPR.  On the PSK side, SIM-31, very infrequently used, nevertheless has tweaked PSK-31 to become a fully automated mode; no human necessary!

You can also make the same kind of argument for using any digital mode where the signal cannot readily - or at all - be interpreted by a human without the use of a machine.  Modes such as RTTY, OLIVIA and countless others, cannot be used without machine decoding.  Yet, nobody makes the argument that these are invalid QSOs.

In the digital age, the human could be made to be entirely redundant in forming a 2-way QSO.  In some cases, the human is already redundant.  It's simply a matter of preference and, frankly, mindless prejudice that prevents some folk accepting new modes and that direct human involvement in QSOs is not always necessary.  Sure, it insults our sense of pride and importance to be cast aside.  But, this should not detract from the motivation to make and operate efficient, low power stations that modes like WSPR engender.

Amateur radio, in the end, to most people, is about "how far can I get with my set up?"  For an awful lot of people, WSPR and modes like it offer a very enjoyable way to 'work the world' on very low powers - often milliWatts - with extremely modest or compromise antennas.  I don't think anyone should deny folk that satisfaction by saying that, for some nebulous and improperly-formed reason, WSPR QSOs are in some way invalid and may not count for recognition.


Long live WSPR!



12m Propagation Looking Good

After a couple of weeks where the Sun has been causing havoc on the bands, 12m has returned!

The beam's been busy this weekend!


Propagation has been strong towards the Caribbean and Latin America, but very little has been heard from the US.  Last evening, the propagation continued almost into total darkness in Wales, making it about 22:00UT.  Some nice strong signals came in later this afternoon from central Chile, which is always very welcome.


It probably won't last for long, with the summer doldrums approaching. So, time to make the most of it!


Saturday 11 April 2015

6m Begins to Open!

High pressure has been building over the UK the past several days, although a spell of poorer weather is making its way in by now.

Propagation on 2m has been very good.  Six has also been showing signs of life, with good trans-equatorial propagation on WSPR.  For the moment, more northerly latitudes in the UK - like me - have to be content with the occasional weak signal from within the country.  M0EMM at -27db and G3NFB at -25dB were my first 2015 six metre WSPR contacts, but they didn't hear me.  They were probably just aircraft reflections, anyway!

A few fishing rod spreaders and some wire.  6m fun, the cheap way!

Of course, all my six metre activity comes courtesy of a bargain-basement, homebrew 2 element quad.  A 1/4 matching stub yields a flat, 1:1 SWR, and it's really proven its worth on Es, meteor scatter, and even aurora scatter recently.  Best of all, it flies through the worst hurricane-force winds with barely a ripple; it's now in its fourth season, with no damage.


Wednesday 8 April 2015

ZL7E - Look North!

Well, here comes another DX!  Superbly strong signals straight over the North Pole this evening as ZL7E Chatham Islands attracted a typically huge pile up around the grey line time.

Venus shines in the west as the Yagi beams ZL7E over the North Pole this evening.

The old Innovantennas LFA Yagi did very well again, busting the pile up after only a couple of calls.

Glad to say ZL7E was running a very efficient operation.


2m is GO!

The strong temperature increases and high pressure over the past few days in the UK have had a positive effect on 2m propagation.  About three days ago, I was again having strong, stable QSOs through repeaters out to about 165 miles distant, using only 20W and a homebrew copper pipe SlimJim.  Forget the stupid debates about 'gain' of SlimJims - all I can say is that this one flattens the meter on all the local stations, and is in every sense a very successful omnidirectional antenna. 

My homebrew 2m SlimJim.


Then, over the next couple of days, good simplex DX started rolling in.  Not the long-haul stuff, you understand, but certainly out to 80-odd miles on 25W.  Stations down in Newquay (SW Wales) and Port Erin (Isle of Man) were nice and strong, allowing a change from the same old handful of local 2m ops!

So, it's once again time to scratch my head and figure out which commercial beam will replace the beautiful and very successful 5-element quad that the XYL recently broke whilst reversing the car.  Grrr!!


Saturday 4 April 2015

Happy Easter, Idiots!

Yes folks, it's Easter holidays in many parts of the world!

This brings better weather, slightly worse HF conditions - and very bad operators!

We see this deterioration in operating every weekend.  They seem to be people who switch on from time to time, with little regard for basic respect towards other hams.

Take, for example, this morning's opening sequence on 20m JT65A.  I called CQ, had a nice return from LY2BOS, to whom I reported his signal.  Who comes back mid-QSO?  It's some Belgian station who probably saw a callsign on his screen, clicked on it with no regard as to whether there was a QSO ongoing, and tried to bag it for himself.

I wondered whether this is a result of transferring lots of the ham band experience onto computers these days.  Are operators beginning to think of the bands as some click-down menu that has no consequence in physical reality?  I'm sure that is the case for some.  But then, we have always seen greedy, inconsiderate and over-competitive people on the bands.

Still, my response to this behaviour is one of minor irritation, followed by switching over to another mode or band.  For sure, I had no intention of answering the Belgian station!