Curious Es

A strong opening on 10m yesterday, with a fascinating, apparent concentration of stations during mid-morning that persisted for about an hour before a much wider spread of EU stations came into 'view':

An interesting NNW-SSE concentration of FT8 receiving me yesterday.

Some people look normal, but aren't.

12m was nicely open to various places this morning.  I was busy sending out a few CQs on FT8, noting that there was another GW station operating a little further down the waterfall.  His signal was about -8dB.

Then, all of a sudden, a superficially outstanding call from a XR station - Chile!  'That's odd!', I thought.  He would be to the back of my beam, at the wrong time of day.

Even more curiously, his signal strength was, you guessed it, also -8dB.  It was obvious this local station had sent a false callsign, for reasons that can only be described as idiotic.

Now, I haven't had much to say to this other Welsh operator over the many years I've known he's around.  Someone in the CDXC, a UK group, told me that "all the big contesters are active with us, except for..."  He implied this operator had difficulty getting on with others.

I had previously had a minor bad experience with this operator when I was trying to complete a difficult QSO with the Far East one day.  Instead of being patient and waiting for what was obviously going to be a successful 2-way contact within a few seconds, my compatriot, who spends very large amounts of money on installing large antennas, decided to simply take over the QSO and claim it for himself.

I'm afraid that people like my not-too-distant colleague don't impress me much.  They put their aggressive point scoring ahead of absolutely everything else, including their individual and country's reputation.

Even sadder is the realisation that this operator actually takes some considerable pleasure from showing off to others by interfering with their QSOs.  'I can do it, but you can't, ha ha ha', seems to be the message.

I simply take pleasure from making good DX contacts with modest equipment and low power.  No need for phallic substitutes here, thank you!

This is not a man with no life who shuts himself away and has lost contact with the real world.  He's obviously quite well-off, and travels a fair bit.  You get people like this - people who refuse to comply with courtesy, rules and conventions - in aviation, too.  Having had so much money that they don't ever have to listen to anyone else, they get in everybody's way, irritate people, and sometimes become dangerous to themselves and others.

So, if you hear someone struggling to make a QSO, don't just jump in and take over.  Be considerate and realise the other person would like to complete the contact and put it in the log.  You do yourself no favours through blatant and impolite butting-in.  And certainly not by transmitting a false callsign to make what you perceive to be fun of other operators.

'No money' go-box.

Over the past few days, I've been working on a 'go-box' for HF, including digital capability via a Raspberry Pi.

This was motivated by my occasional struggles at the beach, trying to keep ahead of the incoming tide.  The problem was that I had the Pi computer in a backpack, which was connected to the rig by a single USB cable.

How it used to be: rig in one box, Pi in a backpack.

When I had to move, I had to move the rig box and the backpack together, without disturbing the connection and having to restart the Pi, which would mean lost WSPR spots.  I can actually move the antenna by several metres without disturbing reception.

There is a very nice Facebook page about go-boxes.  But this is a very America-centric page, where big money is spent on boxes that, in many cases, are so big and heavy that they look more like no-go boxes to me!  Their idea is something they can fling into the back of a car when hurricanes hit, whereas I'm after a single-purpose HF system where I have to walk the equipment to the beach.

Anyway, I decided to attach a piece of wood with self-tapping screws to the lid of my 25-year old plastic toolbox, then screw my Waveshare 7" screen onto that.  The Pi is attached by cable ties fed through holes drilled in the reinforcing of the lid.

This is the system, undergoing at-home testing on 14MHz WSPR.  As they say, it doesn't have to look pretty, it just has to work - and cost nothing!

All in one box now.

A nice treat for you...

For those who have been following the WSPR activities here of late, which have focussed on VK3MO and VK3QN, then you may have wondered what the various set-ups at VK3 look like.

Now, thanks to Ian, VK3MO's kind consent, I am able to share with you the fantastic images of VK3QN, which was set up a couple of years ago with the aim of utilising low angle radiation.  In this respect, it does very well, usually being about 3dB stronger than VK3MO, which has 8 more elements in operation by comparison.

This, then, is Ian's very professionally-installed VK3QN WSPR 'beacon', as it is currently being operated, with a slightly odd aspect ratio due to the mobile phone camera used to capture the images:

VK3QN hilltop, sporting a 2 x 6 element 14MHz array.  Image (C) Ian Williams, VK3MO.

What dreams are made of.  VK3QN fixed on long path Europe (130 degrees).  Image (C) Ian Williams, VK3MO.

The VK3MO 4 x 5 element 14MHz array.  Image (C) Ian Williams, VK3MO.

Gravity Waves and Es

My blogging colleague John, EI7GL, yesterday enquired about the modulation of E-layer ionisation, with a focus on internal atmospheric gravity waves.

Gravity waves (GW), first of all, should not be confused with gravitational waves.  The latter are a distortion of spacetime, whereas atmospheric GWs are simply waves whose restoring force is gravity that occur throughout the atmosphere.

A GW starts its life as a fairly small amplitude disturbance near or at ground level.  Mountains are a particular cause of GWs, notably when strong winds blow over them, launching waves into the atmosphere.

Once caused, GWs grow in amplitude as they propagate upwards through the atmosphere.  They do so quickly, also extending out to very large distances, well away from their source.  Wind velocity at ~90km is typically 100-400m/s.  Watch the video of GW modelling below, noting particularly the scales involved for the 'upper atmosphere' bit (which is actually more properly called the middle atmosphere), and the little time indicator - see how quickly the waves spread:


Here's a real example of gravity waves off Western Australia modulating cloud condensation, though this is obviously only at a few km up, in the troposphere:


Once GWs reach the top of the mesosphere - the kind of height used in the second part of the video, they start to break.  That is, just like water waves, the stuff coming up from behind overruns the stuff in front, becoming unstable and breaking, where they dump their energy.

Upwelling due to GWs is the mechanism by which the mesosphere becomes the coldest part of the atmosphere - roughly minus 135 degrees Celsius.  It does this in midsummer, which seems a bit counterintuitive, until you remember that a rising parcel of air, all other things being equal, will expand and cool.  The expansion is large, and so therefore is the cooling.


What does all this have to do with Es and radio?  Well, the GWs are propagating in an area where metallic meteoric debris is deposited and floating around.  By 'debris', I'm talking very small - nanometres only.  In summer, this accumulates a coating of ice, which doesn't make them very much bigger; they may get to a couple of micrometres, still only the size of a typical bacterium.

The exact height of the E and D layer varies, but Es happens round about the upper D and lower E regions.  It is usually misleading to think of fixed boundaries of the kind that atmospheric layer diagrams present.

All this metal and ice is highly charged, and certainly strongly reflects frequencies around 50MHz, which is where middle atmosphere radars operate.  Indeed, there are accounts from WW2, when the Chain Home radar system around the UK was operating (at around 30MHz), of enormous squadrons of German aircraft being detected, but never appearing over Britain.  The cause was almost certainly strong Es, though it would not have been understood as such then.

So, gravity waves and the charged particles they 'push around' present a rapidly and ever-changing landscape of modulated charged particles to radio waves, which can and do reflect off these wave fronts and their associated, complex structures arising from other effects such as windshear.  We can often hear these effects in sudden periods of very strong signals (much longer than meteor scatter, for example), and then sudden drops to nothing.

Thunderstorms produce GWs through their very strong convective nature.  So much air is going upwards, and so quickly, that they produce GWs in the process.  These again travel into the E region, where they modulate the charged particles.

Summer echoes from the mesosphere.

The phenomena of PMSE (Polar Mesospheric Summer Echoes), Es and NLC (noctilucent clouds) all show much the same seasonal variations, because they are all, in essence, caused by the same processes.  Of course, PMSE can also occur in winter, possibly due to infrasound from rough seas, as can Es.  NLC only occur in summer, because that is the only time when water and temperature levels are correct.  A link between the occurrence of NLC and 50MHz polar propagation from Europe to Japan has often been offered up for some time, and there is certainly cause to consider this possible. 

Well, John, I hope that gives a quick flavour of gravity waves and the things they can cause.  Once you start studying these things, a bit like radio, you only ever have more and more things to find out about - and questions to ask! 

And just a reminder that, from around May 20th until early August, noctilcuent cloud season will be underway.  It's usually the first week in June before they become very active and more easily spotted.

Gravity waves modulating a noctilucent cloud layer.  Wavelength is of the order of tens of kilometres.

Complexity of NLC. 

Final Vertical/Delta Test

To conclude the comparison of a 1/4 wave vertical (two elevated radials) and a vertical delta loop (with 16 x ~0.5 wavelength radial groundscreen), here are this morning's results of listening to WSPR from VK3QN, long path at 14MHz:

VK3QN heard at IO73tj, 2020 April 27.  Times UT.

Overall, a median advantage to the delta of 8dB,  with peak LP signals differing at a slightly lower, 6dB advantage to the delta.

Plate capacitor.

I've recently taken up a renewed effort to understand the role of ground in antenna systems, thanks in part to having more time during the lockdown, and also the remarkable results from the coast.

I built a plate capacitor for measuring different soils a couple of years ago, but I never quite finished it.  It was based on the simple design published in the ARRL Antenna Handbook.

So, I fixed the aluminium plates to the frame properly this morning, and provided proper connection points for the capacitance and shunt resistance measurements.

The box has a sliding trap door, which allows the soil to be easily jettisoned once the measurements are complete.  It's important to varnish the inside of the box if you make it out of wood, to minimise moisture getting into the wood and forming a bridge between the plates.  Plastic is probably a better choice if you have any.

Anyhow, here's what I came up with:

Thunderstorm-induced Es breaks out.

Pretty good evidence for today's Es up to 28MHz being produced by thunderstorm activity (you can start your research into this in places such as this paper, and this one, but you can only read the abstract without paying):

Storms over central France and Spain.

10m signals at ~11:10UT

12m signals, same time.

New Raspberry Pi 4B up and running!

For about two years now, I've been running a Raspberry Pi 3B+ as my portable/mobile computer for digital operations. In all that time, in all that banging around and being cooked, then frozen inside a car every day, the Pi has never failed.

Fairly slow, but painless test installation of the new Pi 4B, already running WSPR.

With this success in the background, I thought I'd try a Pi 4B, with 4GB RAM.  One thing I expected would make the 4B less attractive than the 3B+, itself a very capable and fast machine, is the added power consumption, fed by a lot of anxious online talk - as there also was when the 3B+ came out - about CPU heat.  I elected to fit a passive aluminium heatsink case because of this, instead of a standard plastic or metal case.  I used heat transfer compound to make contact with the chips, rather than the supplied pads.

It turns out, though, that at a fairly typical resorce load, the 4B only uses about 6% more power than the 3B+.  With all the cores pushed to the limit, the difference increases to 31%.  But use of WSJT-X is fairly undemanding, and so we can assume something like the lower limit for this application.  The heatsink proves to be only hand warm when running WSJT-X - nothing to worry about there.

What does this mean in practice?  Well, I can run the 3B+ plus its 7" Waveshare screen for at least 5 hours, and probably much longer from a small ~20Ah Li USB battery pack.  So the 4B should not suddenly see usable times come down dramatically.

Pi 4B decoding nicely!  Waveshare 7" LED touchscreen (with my own timber frame, to attach to a 'go-box' lid later on)

The real question is: do you need a 4B and its slightly higher power use for field digital operations?

My view is: no, you don't, even though the two versions cost much the same.  The 3B+ is perfectly good enough for all digital modes and has, I think, the perfect balance between performance and power use.

I can't see anything other than a marginal increase in decode speed of weak WSPR signals with the 4B.  The 3B+ has also proved itself over and over again, although there's no reason to doubt this won't also be true of the 4B.

UPDATE: I ran the Pi 4B for 4 hours and 10 minutes later in the day.  At this stage, the USB battery was still only half empty, although it may be that non-linearity in discharge means we can only expect maybe another 60-90 minutes of further reliable operation.

So, roughly 5-6 hours' operation from a hand-sized power pack, with plenty of waking the screen up during this period, is a very good result and indeed much the same as that seen with the Pi 3B+.

Accurate temperature measurement with a DMM probe inserted into the heatsink fins.

Decoding speed is a couple of seconds faster than my HP laptop with decoding set to 'deep' on both systems.

Interestingly, the Pi 4B doesn't seem to produce the RFI that is often seen with a 3B+, which can be quite strong, even when housed in a metal casing.  This strongly tips things in favour of the 4B for radio work. 

Despite having all that aluminium in intimate contact with the board, wifi connection reliability remains excellent.  Similarly, the Bluetooth connection outdoors is good out to around 15-20 metres in the clear.

Temperature measurements with a multimeter probe inserted deep into the aluminium heatsink gave 37 degrees Celsius after an hour of operation (ambient = 18.5 degrees C), confirming the low resource demand of WSJT-X.

Anyway, I've a fairly exhaustive page on setting up the Waveshare screen and some advice on WSJT-X set up here.

Is it just a mirage?

My blogging colleague, Bas, PE4BAS, rightly questions whether some or all of the signal enhancements seen from the beach might not be a product of differences in the equipment used?

This is a very important point, which deserves more than a dismissal based on received wisdom from the texts about antenna theory and ground characteristics.

The reflection of the setting sun's light gives an idea of how low-angle radio waves are acting at the beach. (The Sun is 0.5 degree in apparent diameter, to give you an idea).

So now is a good time to review why we would expect operations at the coast to yield the kind of benefits that others report.

First of all, you can look at a video (sorry, embedding doesn't work very well) of 100mW SSB making it all the way, if only marginally, to VK from G7AKC/PM at the coast.  You can certainly clearly hear the words '100milliwatts' coming through; sadly they didn't test it out a bit longer, beyond the tuner interference

Now, you can try getting 100mW SSB from a simple vertical to VK from an inland location, but I politely suggest you are exceedingly unlikely to succeed.

Next, I can rely on TX-only WSPR work from the beach, also running alongside my delta back home.  This uses the exact-same transmitter, the WSPRlite, with power settings that I've confirmed are within the stated +/- 11% limit.  This results in enhancements of the level reported, for example, here.  As there are no material differences in the transmitter or output, then the enhancement from the coast can only be due to the location.

Next, we know that seawater is a near-perfect reflector of HF, affording extremely low ground losses and very low angle radiation.  Many people have studies this over the decades, and so I don't have to (nor am I competent to) go back to first principles to demonstrate it is true.  Actually, my own view is that the vastly reduced ground losses account for most of the enhancements seen, but that a clear sea horizon is obviously beneficial to some extent, too.

Anyhow, despite being extremely tired, I decided to run the home equipment (FT-450, delta loop, WSJT-X latest version (2.1.2), Win10 laptop, ZLP data interface), alongside my TS-480SAT, 1/4 wave vertical, WSJT-X latest Raspbian Stretch edition (2.1.2), Raspberry Pi 3B+, ZLP data interface.  Of course, the 1/4 vertical has slightly less gain than the delta loop, so we should expect to see not very much difference if the other equipment is operating at the same kind of performance.  Certainly, we shouldn't see 19dB difference!

Here's what multi-platform testing (this is a day later, testing a Pi 4B) ends up looking like - a mess!

What, then, do we actually see when this is done?

Here's the comparison of K5XL using 1/4 vertical (the coastal set up, MW6PYS), and the home set up, vertical delta loop (MW1CFN).  The result is the 'wrong way around' to explain the coastal enhancement (because the delta is much stronger, by a median 6dB, relative to the 1/4 wave vertical).  We can say that, were I using a delta at the beach, the signals received with it would be even more remarkable!

K5XL heard by the coastal set-up (blue) and home delta (orange). 

Let's look at another good DX, VO1DZA, same equipment order:

Again, notwithstanding one less spot for the delta, the result is much what we expect (if we take three spots for each, then the median outcome is exactly the same, at -13dB).  I'm will again have to check how my 1/4 wave vertical compares with the delta later!

UA9SY's signal produced a median -14dB from 13 spots with the 1/4 wave vertical, but a stronger, -5dB from 14 spots with the delta loop (I'm glad the delta is doing as it should now!)  Again, that is a result 'the wrong way around' to explain the coastal enhancements.

7Z1WW, whilst only one spot during the test, produced +2dB for the 1/4 wave vertical, but +4dB for the delta .  Again, the kind of expected benefit to the delta, wholly discounting any equipment discrepancies.

Here's a plot of both systems, done a day later than the above, using a Raspberry Pi 4B rather then the 3B+, receiving ZS1SCI.  It again confirms that the +4dB in favour of the delta loop is 'the wrong way round' to explain the beach results.  The difference with boths systems operated at home is down to the delta being, in effect, a pair of closed-spaced, phased verticals, the other system being just a one element vertical:

And, finally, the definitive morning long path test of the vertical ('beach') set-up against the delta ('home') set-up, both located, of course at home for this test.  Clearly, the fact that the delta is hearing VK3QN significantly stronger (median of 4.5dB better) than the vertical is, yet again, the 'wrong way around' if the beach set-up enhancement is down to equipment, not location:

I could go on for hours with this, but it's pretty clear that the enormous differences between home and coast are a product of location, not equipment.  That may well be, in the end, a combination of slightly less RF noise at the coast, much lower ground losses, and the low angle, near in-phase reflected signals accessible from the surface of the sea.

If you are an expert in these things, please do leave a comment to inform us further!

Final LP coast work (for now!)

Thanks to a mutual interest in low-angle propagation, and the willing cooperation of Ian, VK3MO, I was able to run two WSPR receive systems again this morning to determine the difference between a 12-element low angle optimised array, and a 20-element general installation at 14MHz, both beaming 130 degrees, long path Europe from VK3MO's QTH.

Ian is more interested in differences between the two systems across the whole day.  I am more interested in long path, especially morning LP propagation, when very low angles are likely to be more important.

Beach set-up on an earlier outing.  Hint: use a Raspberry Pi system for WSPR, not a laptop!

Indeed, this is what the results show.  Across the whole day, the two systems typically return about 1dB or less difference in signal (in favour of the low angle, VK3QN system).

But, at morning long path (Wales), the difference in favour of VK3QN becomes more like 3dB, as it did this morning.

But, of course, this does not allow for the fact that VK3QN has eight fewer elements in operation than VK3MO.  To my mind, that means the smaller array of VK3QN is, regardless of time of day, doing very significantly better than VK3MO (noting that 'smaller' is huge by most people's standards - a 2 x 6 element 14MHz array!)

With Ian's consent here's the fabulous VK3QN, fixed long-path system:

Anyhow, here are the latest results, probably the last for a while now.  Coast data are the two strongest curves (labelled (C)), and my slightly inland delta loop the lowest two curves (labelled 'I').  Note the enormous difference between coast and the delta back home, peaking at 19dB (power factor of nearly 80 times) stronger at the coast!  Because the delta has a measured 6dB more gain than a 1/4 wave vertical (a delta is essentially a close-spaced, phased pair of verticals), the real difference is more like 25dB!  Note that this kind of gain is probably only available for this path, at this time; it's likely to be significantly lower for other DX outside of long-path time.

Are you blighted by RFI back home?  Why worry?  Even a quiet rural area is rubbish, compared to the coast!

 

 

Same (inland) site comparison of 1/4 wave vertical and full-wave delta loop at 14MHz for the reception of long path signals from VK3QN.

 

The propagation that leads to all this is revealed, probably quite accurately, by Proppy HF, but is a little different to what one would imagine.  If you compare this with a plot of the antipodean point from VK3MO, which is not far from the Azores, then the propagation is seen to centre there; no doubt, there are complex paths, including antipodean focussing, present.

Proppy HF prediction of propagation at 07:00UT today.

Antipodean point to VK3MO/VK3QN

 

For the record, here's a plot of all the main stations heard (V51 heard only once, hence no line):

G1 Activity, and a delayed WSPR effect.

The geomagnetic field was quite disturbed yesterday, reaching KP = 5 around the middle of the day (20/04/20).

This is the OVATION modelled aurora image at around the time of peak activity:

Image: NOAA/SWPC.

The magnetometry looked like this:

Disturbed earlier in the day, but quiet by evening.  Image: Tromso Geophysical Laboratory.

From about midnight onwards on a quiet geomagnetic day, I only hear groundwave WSPR signals near the limit of detection (usually around -30dB) from the UK and Ireland at 14MHz.  Only by about 04UT do signals from afar start coming in.

But last night and early morning, I was hearing LA6GH strongly, which the top plot shows is entirely anomalous in never having occurred in the preceding evenings (the relevant period is highlighted for each day in blue box).  The receiver runs from late evening to mid-morning, not daytime, but that is immaterial for this discussion.  The lower plot 'zooms in' on the detail of 20-21 April (long horizontal lines indicate periods during which no signal received):

LA6GH 14MHz 100mW WSPR received at MW1CFN.

Much the same was seen with the 5W signal from OZ7IT, where signals within the last shaded period at right (20-21 April 2020) are clearly seen as anomalous, relative to the same periods in earlier days):

OZ7IT 14MHz 5W WSPR received at MW1CFN.

It seems this is a result of ionisation 'patches' remaining in circulation in the ionosphere, several hours after the peak geomagnetic activity.  Nothing very unusual, but a nice clear example of enhanced propagation, all the same.  Apologies for necessary laxity in axes labelling, etc - these plots and posts take a long time to prepare!

VDSL - The Great RSGB Campaign

I'm frequently a critic of the RSGB, mainly because it has tended not to adequately address the real concerns of typical operators in the UK, such as planning and RFI.

But, progress is underway!

Yesterday, the May edition of RadCom, the RSGB's magazine, carried a full-page letter from the President, calling every member who suffers from VDSL interference - previous surveys suggest up to 50% of operators do - to measure their spectrum and complain to OFCOM, the UK regulator.

I have done a simple 'by ear' test of the bands here when the RSGB last took an interest in this topic, and there was no real sign of VDSL noise.

This time, the RSGB has a spectrum analysis tool ('Lelantos') which anyone - including non-members - can download for free and use it to analyse very short (~0.5s) I/Q recordings made using any SDR device.  You can find it, and plenty of information on the methodology and software, here.

This is what we expect to see where VDSL RFI is present - two timing signals that are very prominent:

Image: RSGB.

I'm glad to say that none of the amateur bands show any evidence of VDSL interference here.  With fibre optics, and not copper wire now providing all telecoms in the locality, all the way to each property, it would also appear that it will never become a problem here.

Here is the analysis of my 20m band recording, and the random noise in the lower right graph panel shows no timing signals:

Well-meaning, but is it lawful?

Occasionally, I have a look at the RSGB's website.  This morning, I had a look to see if they were doing very much about World Amateur Radio Day, and/or the role of radio in reducing social isolation.

In fairness, the RSGB is doing something, though I have yet to see anything about amateur radio on the mainstream media outlets, despite there supposedly being a press officer being employed by them.

But what struck me as a bit odd was the callsign displayed in the following image, proudly displayed in the vein of support for the 'heroic NHS' on the RSGB's site, showing an unusual callsign being used actively on JS8 Call:

Image: via RSGB web site, accessed 08:40UT, 2020 April 18.

The rules over callsign extensions in the UK are not especially clear.  For a start, the rules on this are merely 'recommendations', not legal directives.  They appear only in the Notes to the licence, and the primary legislation makes no mention of such things.

But in general, extensions after a main call are normally only used to indicate a location other than the licenced address - /P, /M, /A etc.  Things like /MM and /AM are occasionally seen, and also generally accepted (and indeed recommended by OFCOM) as providing useful information about the operation's circumstances.

So, being recommendations, I suppose you could say that the /NHS extension is not unlawful or wrong in any strict sense.

In fact, someone helpfully - or perhaps worryingly - referred me to this page, which announces 'OFCOM is happy' to allow /NHS to be used.  This would seem to be ad hoc lawmaking, of the kind certain Police authorities have engaged in recently.  Or maybe just confirmation that there are no enforceable rules about extensions.  Or maybe that OFCOM don't enforce any rules.  For sure, OFCOM would never be seen to act against any support for the NHS at the moment, even if it had been unlawful.

But all this is certainly out of keeping with the general way in which special callsigns are allocated by convention (and law) in the UK - the use of the (free and automated) Notice of Variation (NoV) of the licence.


And, despite the global rules of the ITU, IARU and the like, Cyprus doesn't seem to have a problem with this health message mouthful, seen on 15m today:

Anyway, virtue signalling has become something of a popular pastime in the UK at the moment.  Anything that might look like criticism of, or less-than-next-door's support levels for the NHS is instantly jumped upon as evidence of being 'un-British' and a traitor.  Ho hum...

Warning! Radio Politics.

Readers may recall my frothing at the mouth recently in response to a very curious activity being undertaken by OFCOM in relation to EMF safety.

'G' amateur operations are very different from '5G' telecoms...

Without a shadow of a doubt, the overriding motivation for OFCOM's consultation - which the RSGB seems to think is perfectly sensible - is the introduction of 5G mobile telecoms to the UK.  Recently, there have been a number of cases of 5G masts being burned following social media claims - obviously wholly untrue - that 5G spreads Coronavirus.

Now, quite what 5G microwave transmitters have to do with amateur operations is anybody's guess.

But then I decided I wasn't going to guess.  I was going to require answers.  In my experience, the RSGB, when pushed into a corner, doesn't like providing answers.  Indeed, as a limited company, it  does not legally have to respond to requests for information - even from the members who pay for its very existence.

So, in about a month's time, we should have information from OFCOM, who are legally obliged to answer, that may shed some light on exactly how we came to be in this stupid position, and what role, if any, the representative body of amateur radio in the UK had in it.  For those of a nervous disposition, the following is very dry and adversarial for a reason: give a public authority half a chance to avoid answering difficult questions, and it will...

Freedom of Information Act 2000

I make a request for information pursuant to s1(1) of FoIA 2000 as follows, noting that if this is not the correct email address/recipient, I am not obliged to do anything other than successfully deliver it to OFCOM; it is for OFCOM to communicate the request to the correct person internally:

In relation to your recent consultation on the proposals to compel mobile phone operators and amateur radio operators to ensure compliance with radiation safety (EMF) measures, please provide the following:

(1) Information, to include full citations, that demonstrates (a) academic or other similarly authoritative and reliable evidence of harm or likely harm caused by amateur radio operations (and not mobile telecommunications operations) within the UK or without, mindful of the typical limitations upon amateur operators, notably the relatively low antenna gain available, low legal power limits, very low duty cycles, and distance of antenna from a typical, realistically-presented exposed subject within the context of UK installations.  For the avoidance of doubt, the latter stipulations should not consider such examples as a person standing at 1m in front of a 4-element Yagi antenna at 400W input power as realistic.

(2) Information, in its widest sense, that demonstrates the route within and without OFCOM as to how and why amateur radio operators in the UK came to be included with mobile phone operators.

(3) Information, in its widest sense, as to how and why the OFCOM consultation response form has as its file name 'response-form-5g-emf', which indicates the consultation always had as its motivation the roll out of 5G, and not concern over amateur operations.

(4) Information amounting to, in practical effect, copies of all correspondence between OFCOM and the RSGB (including the reverse direction), concerning this consultation and proposals, within the period January 01, 2018 to the date of this request, inclusive.

(5) Information, in its widest sense, amounting to, in practical effect, copies of internal and external correspondence concerning this consultation and its proposals within the same date range as (4) above.

Please note that, pursuant to s1(b), such information as you hold in relation to the above points must be communicated to the applicant within the statutory period of 20 working days (which is not relaxed by the present pandemic).

Please note that section 77 states that it is a criminal offence to alter, block, destroy or conceal information. Depending on the nature of the incident, an authority or its individual members of staff could be charged with this offence. The penalty is a fine.

It is not expected that an exemption may be lawfully applied in relation to incomplete, ongoing work/reports, because the enquiry is not concerned with the outcome of your consultation, merely information leading up to it. Any other exemption you may wish to rely upon should (and must by law) be clearly cited.

Please note that consent to transmit or use personal details outside of those persons reasonably required to respond to the request is not granted, and if not observed, will breach Data Protection legislation.

Please note that attempts to block publication of any FoIA 2000 response under The Copyright, Designs and Patents Act 1988 will not be observed or enforceable, given the specific exemptions provided for news reporting and fair comment.

That Douple Peak...

John, EI7GL, raised a question yesterday as to the cause of an apparent 'double peak' in 14MHz WSPR signals received from VK3MO and QN (operated by the same person).

This graph is very typical of what happens in the morning in Wales:

I used VOACAP to predict the signal strength for both long and short path.  The standard input parameters to this can't hope to accommodate the type of vast arrays that Ian is using, but an 8-element Yagi beaming LP Europe at maximum height is used, together with CW-equivalent output of about 1kW, to approximate the WSPR reality.

I think the results, within the constraints of VOACAP's once-per-hour computations, confirm very nicely that the first peak is the result of the short path. This (purple, 14MHz) peak is predicted to be - and is often confirmed in practice - slightly weaker and broader than the second peak, which comes ~40 minutes later, and is the result of a switch to long path (probably still with some influence from short path).

Short path signal strength prediction, VK3 to Wales.

Long path signal strength prediction, VK3 to Wales.

Turning to Proppy's output on area coverage, again assuming a large Yagi array and LP Europe heading from VK3 (this time, using ~25W FT8), it becomes quite evident as to how complex the various paths from VK to Wales are at the moment:

This is my best attempt at understanding the situation.  Maybe you have a different analysis, in which case, I'd be only too happy to learn about it, if you leave a comment, below.

Results: VK3MO vs. VK3QN

As earlier reported, Ian, VK3MO, is currently running a long-term WSPR experiment to determine the role of low angle radiation across the solar cycle.

For this, Ian is using 5W input into VK3MO, a 4 x 5 element Yagi array on a 200 foot tower, and the same input into VK3QN, a 2 x 6 element Yagi array optimised for very low angle radiation, on a 66 foot tower.

For this comparison, both antennas are beaming long path to Europe, so my results are based on reception during the breakfast time period here.

The following plot is typical of each morning's results:

For the peak signal at long path period, VK3QN, the low-angle optimised array, which is 12 elements total, is a median 2.5dB stronger than the 20 element array of VK3MO as determined over five consecutive days.  The maximum difference between the two signals was 4dB in favour of VK3QN, and the lowest difference was 0dB.

Very interesting that the low angle optimisation of a 12 element array achieves a received signal during long path that is nearly double the strength of a 20 element array, even though the former is at considerably lower height overall.  

Raspberry Pi 4 - new connector types.

Having finally collected a keyboard, mouse, screen and Noobs disk together, I thought I'd fire up the new Raspberry Pi 4 this afternoon.

Screeeech!  Came to a sudden halt as I tried to connect it to some power: it uses a USB-C connector, not the ones we have grown used to over the years.

So, in case you are wondering, or about to embark on your own Raspberry Pi 4 adventure, here is the diagram I should have consulted days ago (note also the HDMI connector is now changed from a full sized edition to a micro socket - very annoying and much less robust in the field):

Courtesy, Seeed Studio.

Also, if you find your Pi doesn't appear to boot when you fire it up, make sure you have the display fed from the left side port, because this is the primary display.  I was looking at unchanging colour pixels for ages, not realising the right-side port I'd connected to was not the correct one to use.

Details:  https://support.thepihut.com/hc/en-us/articles/360001887937-My-Raspberry-Pi-4-will-not-boot

Most Northerly WSPR Spot.

I was glad to see the RV Polarstern appear on the WSPR waterfall this afternoon.

Hannes Grobe, Alfred Wegener Institute

At 84 degrees north, this is the most northerly WSPR (or any other) spot I have ever received.  At this far north, the ship is only 630km from the geographic North Pole!