Tuesday 31 March 2020

Amateur Radio - the Covid-19 Files.

How is your Covid-19 crisis going?  Here in the UK, as many countries, there are fairly severe restrictions on travel and general movement.  In essence, we can only leave the house for shopping, work that cannot be done at home, and other such essentials.

Courtesy Mark For Europe, FB.

As it happens, all this difficult situation has come just when I have been examining two different WSPR sets ups operated by Ian, VK3MO.  He has a multi-Yagi array on one tower, which is a general installation.

Ian's second tower is also a multi-Yagi array, but optimised for low angle radiation.

Luckily, I'm being paid for an article about WSPR, and some of the work for it can only be done from the coast.  So that permits me to legitimately leave home, as does the need to exercise (contrary to what the Police started saying and doing last week, driving to exercise locations is not prohibited in law - so far).

Early morning long path listening.

In any case, the place I go is so remote that I would never seen anyone on a normal day, let alone a restrictions day.

Interestingly, listening to Ian's long path signal in the early morning has shown important differences between listening sites.

For the morning long path period, as heard at the coast, VK3QN (low angle optimised) was a median 10.5dB stronger than VK3MO.

But with the delta loop back home, the difference in favour of VK3QN was only 5dB - with far fewer reported spots.

This result would appear to suggest that it is very low angle signals at this critical time that yields the excellent difference between the two stations received at the coast.  The delta seems to be picking up radiation arriving from somewhat higher angles, where there is less difference between QN and MO, masking the degree to which the low-angle array is better than the non-optimised array.

So, this all kicks-off another round of work, and one which needs a highly-portable WSPR receiver not reliant upon a heavy and power-hungry, conventional transceiver.

What I need is a new Raspberry Pi 4 model, connected to a SDRPlay RSP1a receiver.  Luckily, I won an SDRPlay competition last year, so I already have a spare RSP unit!

I suppose, though, that it will be necessary to wait until the virus restrictions are lifted - which could take some months - before it is sensible to openly go out onto beaches and play around at the coast.  We don't want to give radio a bad name, after all.

New linear PSU.  A small mass on the top stops an annoying casing hum!

Meanwhile, I treated myself to a new linear PSU yesterday, which arrived overnight, despite the restrictions.  It's already in use on WSPR listening duties, though there is no detectable difference in RF noise, relative to my SMPSUs.

UPDATE: The PSU wasted no time in dying, apparently due to a failure in the large transformer windings.  A hum, smoke and that was it - dead - after just three months!  It's on its way back to Radioworld, but I doubt it's easily repairable.  One to avoid, it seems.






Thursday 26 March 2020

VK3MO and low angles

An interesting result on 14MHZ WSPR reception last evening.  VK3MO, who has probably the best antenna systems to be found anywhere on the planet, was sending 5W on long path Europe from a stacked array of Yagis.

Despite the relatively high input into the antennas, and the consequently, vastly increased effective output from them, the signal was heard only by two stations in Europe/Africa.  I was very pleased to be one of those two!

VK3MO reception reports, 3 hours back from 22:14UT 25/03/2020

Tuesday 24 March 2020

28MHz Opens Again

A pretty good opening as far as VP8-land this afternoon on 10m.  Signals are not especially strong, nor are they over on 12m, even with a beam (propagation is a semi-one way type) but they are getting through.

All the plotted reports are for my 20m vertical delta loop operated at 10m.  That's a very-non-ideal, high radiation pattern, but it works very well at fairly extreme DX, all the same:

Reports for my ~20W signal on 10m this afternoon.

Monday 23 March 2020

144MHz Warble

As I'm still fairly new to 144MHz SSB, I wonder if any of you more experienced readers can tell me about the conditions giving rise to this very obvious warble, together with the clipping of low frequencies in the voice, which persisted for a long time?

Digital signals also showed a lot of dispersion.  The auroral oval had extended to reach central Scotland at the time, but I'm not persuaded it's auroral propagation, even though it sounds like it.  The signal was from my east at the time, and beaming to the north saw the signal almost disappear, seemingly confirming it wasn't auroral (although my 8-ele is far too narrow for aurora).

Saturday 21 March 2020

T10 Mode Weekend

The Russian Digital Radio Club is having a T10 activity weekend at the moment.

I had a go at this for a while this morning, but soon gave up.  JTDX proves not very good at decoding the mode in a consistent fashion, especially if more than one station is calling.

So, that was the T10 weekend finished!


Friday 20 March 2020

Chokes - too expensive!

Seems like over the past year or so, chokes of coax-and-sleeve ferrite types have become popular items on offer from commercial outlets.  Typically, they cost upwards of £30.


Whilst a choke of this sort might look a little tidier, you can easily make your own air-wound version just by rolling a few coils of coax around a plastic pipe.  This both saves you money and reduces the extra losses introduced by additional connectors.
Type 31 ferrites for sale on Ebay.

If you really want a linear, rather than coiled choke like this, you can buy the ferrites off the likes of Ebay for about a quarter of the price of a ready-made, commercial offering.


These days will come again

I came across some audio recordings from 2015 this morning.

Our radio reflector in the sky!  Image (C) J. Rowlands

Just think, when the Sun wakes up, the aurora will dance and coronavirus will be a distant memory, we will enjoy SSB aurora QSOs on 6m once again!

Monday 16 March 2020

Amazing opening on 10m (or was it?)

Things were looking good on the higher bands since first thing this morning.

My 10m antenna is pretty basic, but is efficient: a 20m vertical delta matching perfectly at 10m.

Despite this simplicity and extremely non-ideal radiation pattern for DX (it becomes a E-W dipole pattern, with a broad, very high lobe), I got a remarkable report from DS3SHI, who appears to have a Yagi of some sort beaming 035 degrees (i.e. towards North America).  At the time, it was around midnight over there:

First spot. Terminator correct for spot.
The path seems to have been relatively stable, as my ~35W FT8 was spotted again a few minutes later.  Sadly, perhaps as it was late there, nobody answered my call from DS-land. Or, as PE4BAS comments below, it was simply a case of remote SDR listening?

Second spot. Terminator correct for spot.


Overnight WSPR report 2020 March 15-16

The only unsual 14MHz WSPR spot overnight was EA8BFK hearing me once at 02:46UT.  This seemed to coincide with the usual field restoration to quiter conditions after a minor high latitutde disturbance.

My 1W WSPR signal heard once overnight at EA8BFK
Z field component, restoring to quiet conditions at the time of the EA8 spot.
My signal being heard overnight.  The EA8 spot is definitely field-related, and unique.

Saturday 14 March 2020

Breakfast with France

A degree of tropospheric propagation is slowly building over the eastern Atlantic, as Spring continues to strengthen.

Testing the paths this morning at breakfast time, I was very happy to make a FT8 QSO (8-ele, ~90W, or an ERP of 5.6kW, allowing for computed ground gain) with Normandy, with amazing signal reports:


I doubt this was tropo.  It's more likely to have been a long-lasting meteor reflection, as the signal to and from Normandy was about 15-20dB lower a few minutes either side of the QSO.


Thursday 12 March 2020

Goodbye, VHF FM

Well, it's exactly two years since I wrote of my disillusionment with 2m and 70cm FM.

Today, I'm packing my Yaesu FT-7900 for sending to a new owner.  I haven't used the rig for anything other than the occasional ISS pass - a job now done by my IC-746, which provides the much greater possibilities of 2m SSB/digital operation.

Goodbye, VHF FM.  There was nothing worthwhile there in all the time I had this rig.


Certainly, when one sets up a system with radio, it is generally expected to stay in operation pretty much forever.  So I do slightly regret getting rid of the FT-790.

But the reasons for abandoning FM remain the same as those I gave in 2018: a lot of social misfits, largely CB leftovers in their 60s and 70s (and older), talking unedifying nonsense to one another, and an almost completely dead repeater network locally.

So, £100 goes in the bank, later to help pay for a decent telescopic aluminium pole!



Wednesday 11 March 2020

Amateur licences - the OFCOM data release

I recently made a Freedom of Information Act request to OFCOM, asking for the number of 'live' (i.e. currently validated) amateur licences by category, and also the number of new issue licences.

Hot off the press, here is the data for live licences, as at 1st January of each year:

Live licences by type and year in the UK.  Source: OFCOM, 11/03/2020.
On the face of it, the numbers look fairly encouraging.  The period in question does include the time (2016) when OFCOM decided to start deactivating licences whose holders had not revalidated in the past 5 years, but this seems to have little effect in practice.

Overall, the number of full licence holders is pretty flat.  Foundation holders are growing nicely, though the number going on to intermediate is far less, and at a slightly slower rate.

Curiously, if one adds up all the licence holders (excluding clubs), then we get roughly 80,000 live licences.  Only about a quarter of that figure are members of the RSGB.

Next, the number of new issue licences in a given year:

New issue licences by type and year, UK.  Source: OFCOM, 11/03/2020.
Now the situation is not quite so encouraging.  There's a nearly 7% drop in the number of new Foundation licence issues over the ten year period.

With a new solar cycle 25 about to begin, it may be that, as hinted at in the left side of the graph, when Cycle 24 was climbing out of inactivity, a modest increase may begin shortly in the number of Foundation holders.  But, there may be a prompt there also to keep a sharp eye on whether or not it really is a solar cycle effect that is causing the change, or something more concerning.

Overall, the number of Full licence issues remains essentially stable with time, with a very modest increasing trend across time in the Intermediate level.  For some reason, there is a significant rise in the club new licence issues, though that is not so important, I guess.

So, superficially, a reasonably good outlook for the moment.  It will be interesting to see how the graphs develop as we move through solar cycle 25, which will coincide with the end of active radio for many of the 'Baby Boomer' generation.

Maybe you can analyse the numbers and find other things to discuss?  If so, 'comments' is the place to do it!  But please don't be silly, like one member of a Facebook group, who argued until he looked as stupid as Donald Trump that, after 2017, there was definitely an upward trend in the number of people being licenced at Intermediate and Full levels. 

Sure, the graph goes up, very slightly, for both those categories in that period.  It also went up slightly in the 2010-2013 period.  But two points in a much longer graph a trend does not make.  Overall, it's obvious that the licencing trend is flat, and certainly down for Foundation.  It remains to be seen whether the data for 2020 and beyond will, in fact, show an upward trend, or change to something else altogether.







Tuesday 10 March 2020

Since 1932.

Practical Wireless is a magazine that many operators will have grown up with.  Not surprising, as the magazine was founded in 1932, and has been in continuous publication since.

This month, I'm really very happy to get my own article about seaside operating - the topic of many posts on this blog - into the pages of PW.

My article gets the front cover splash, but it's someone else's photo!

Images may be familiar to regular readers!

I'll be honest and say I wasn't a subscriber to PW prior to rediscovering it when looking for a customer for my article.  Actually, it's a very good magazine, far better than the RSGB's dull RadCom, which is usually in the recycling bin minutes after being received here.  PW also pays proper market rates to its writers.

So, if you fancy a good read, why not consider subscribing?

Monday 9 March 2020

VP8PJ on the high seas

Did you log VP8PJ recently?  I had a look at 20m FT8, and just laughed at all the desperate people trying to get through.  I hate F/H mode, and didn't even bother trying.

Meanwhile, on WSPR at 14MHz, VP8PJ seems to be sending signals from their ship, MV Braveheart, as they sail home to Punta Arenas. 

I was lucky enough tonight to be one of only 3 total stations hearing VP8PJ (at -27dB SNR) from the dark hemisphere:

Global WSPR spots at 14MHz in the hour prior to 19:50UT 2020 March 09.

UPDATE:

The following morning (10/03/2020), I was also doing rather well on a global scale at 14MHz:

Global WSPR receptions of VP8PJ (/MM) in the hour prior to 09:10UT, 2020 March 10
Global reception of VP8PJ (/MM) in the 6 hours prior to 09:10UT, 2020 March 10


Friday 6 March 2020

Radio SETI - end of an era

After 20 years of distributed computing, SETI@home is closing its doors - at least for now.

I've been a participant of SETI@home since the very beginning.  Back then, my PC at work typically took a day or two to crunch its way through the distributed data blocks.  At the time, most data was gathered by the Arecibo telescope in Puerto Rico.

Green Bank, no longer sending data to home PCs.

The reason for pulling the plug seems to be that SETI@home has been re-perceived as a 'first phase' project.  This is news to me, as it has always been presented in the vein of mediaeval cathedral-building: those who started the work would never see the end result.  But, I suppose even mediaeval masons and carpenters changed their methods over time.

Still, science, computing and funding change.  It seems that SETI searches will go on, but that the project is reverting to a more centralised data analysis for the future.

My final two SETI@home work units, nearing completion.

For sure, we have barely scratched the dust on the surface of SETI searches, especially when you spend a moment contemplating the tiny distance our own radio leakage has travelled since we started using that technology, a mere 120 years ago.  Roughly, our earliest radio signals have washed over maybe 15,000 out of 400 billion stars in the Milky Way galaxy.


Thursday 5 March 2020

A prize!

Well, it wasn't difficult to achieve a place, given the few who were taking part.  Hopefully, this event will grow over time.

Monday 2 March 2020

Electromagnetic Safety - more rubbish.



A consultation has recently been launched by OFCOM, the UK telecoms regulator, on proposed changes to licences - including amateur licences - to ensure compliance with ICNIRP controls.

The new compliance controls will apply to everyone using over 10W EIRP.

It doesn't take a lot of reading to conclude that this whole exercise is very clearly motivated by potential concerns brought about by microwave mobile phone operations - with a catalyst being the new 5G system. 

In preparing my early formal response to the proposals, I came to ask the question: why are we being put together in the same room as commercial UHF operators, when most of us stop at 433MHz or so?

That brought me to the ICNIRP's website.  Here, it takes just a click to figure out what's going on.

For reasons that are extremely difficult to understand - but that I have asked the ICNIRP to explain - that organisation uses an extraordinarily unusual definition of HF.

The ITU defines HF in the same way that we all understand the range to be: 3 to 30MHz.

The ICNIRP has the view that the HF range is - wait for it - 100kHz to 300GHz!

Faced with that definition, which nobody yet seems to be challenging other than my response, OFCOM, I suppose, has to go along with it and throw us together with commercial mobile phone operators.


UPDATE 1:

Yesterday, I contacted the RSGB's EMC Chairman.  In a typically RSGB-esque response (dry, humourless, deferential to OFCOM), I was told that the ICNIRP uses 100kHz - 300GHz as the definition of HF because tissue heating is seen from 100kHz upwards.

I was also told that there is "peer-reviewed scientific evidence" to demonstrate this and, by inference, that OFCOM is justified in considering these controls.

I asked the Chairman whether the RSGB could provide me with citations for that evidence.  At the time of writing (05/03/2020), they have not provided any such citations [update, 18 months later: they never did].  I doubt it exists and, if it does, it will almost certainly not be applicable to amateur installations which, in the UK, are limited to quite low powers.  Once again, the RSGB seems to be deferential to OFCOM, going along with much of what idiotic ideas it comes up with next.

Indeed, a 2012 report into non-ionising radiation safety across the EM spectrum by the then Health Protection Agency in the UK, used not the NCIRP's ludicrous definition of 'HF', but the ITU - and our - definition.

Not only is that definition much more in keeping with common sense, it makes discussion, debate and challenge of the effects according to frequency much more possible and meaningful.  The present ICNIRP nonsense is something like saying X-rays at a certain power and duration have the same health effects as visible light under the same conditions.

Turning to ICNIRP, it has found itself in the remarkable position of having a peer-reviewed scientific paper written about its alleged conflicts of interest.  This seems to have been entrirely overlooked by OFCOM.

Another issue to contend with is that of enforcement.  Already, OFCOM is heavily criticsed amongst the amateur community for failing to enforce existing rules concerning EMC issues.  OFCOM is now reduced to not much more than an income-generating arm of government, mainly concerned with selling off microwave spectrum.  There will surely be nobody going around in vans to the furthest regions of the UK and wondering whether that 2m Yagi is just a bit too close to the street to be 'safe'.  There will be, in practice, zero chance of any such unlikely monitoring leading to a Court case.  So what is the point of all this?

In practice, it is to be hoped - as is already mentioned as a possibility - that amateurs will be able to simply submit a standard calculation based on broad antenna type, input power, feeder loss and distance to receiver.  Either that, or be exempted altogether.

Even then, there will be complex things like intervening material absorptions and duration of exposure to take into account in some circumstances.  Absolute measurements would seem to be ruled out, which would require reliably calibrated, likely extremely expensive field measuring equipment to demonstrate compliance to a legal standard.

All this, with an as-yet undemonstrated potential for harm!

UPDATE 2:

A few days after I wrote the above, OFCOM sent me what was in essence a Data Protection response form to complete.
The file name from OFCOM (I added my surname) says it all - all about 5G.  What have amateurs to do with any of this?

And guess what?  My contention that all this started with OFCOM trying to preemptively cover their backsides about potential 5G concerns is more than strongly supported when I looked at the file name of the document OFCOM sent me - 'response-form-5g-emf'  

I rest my case.  But the RSGB seems to think OFCOM is perfect to do all this.  Just as well I'm not a member, then!  [2021 update: the RSGB, presumably seeing a very considerable degree of dissent amongst the membership, came to submitting it "could not support" the proposal in the end].




Online CW Course

I never learned Morse code.  Tell the truth, I never had much interest in doing so.

But Morse does have the 'legacy' value of making it worth learning.  More than that, CW allows us to use very simple, low power transcievers that can make portable operating very attractive.

Having tried a number of programs and online courses, I came across this site, which seems somehow to make the whole process of learning a lot easier.

Why not have a go?