Saturday, 14 October 2017

FT8, Lemming behaviour, Autumn Es, and update.

Ah, the Autumn lull is (not) in full swing.
 A stuffed Lemming. By Argus fin - Own work, Public Domain,

Time for a bit more on FT8. Why not, as everybody else seems to be talking about it?

In my last post about FT8 I outlined the theory which is believed to allow this mode (and others like it, JT65 is potentially better) whereby it works very well on weak signal which are otherwise undetectable. The idea is that low strength reflections are behind this weak signal propagation, with the aid of scattering.

I will repeat the diagram below ..
It is worth pointing out that there needs to be some refraction for the reflection to occur. If there is no F-layer, there is no refraction, and no reflection either (though there may be some scattering). If there was no F-layer at all, such as a night during solar minimum, the signal will proceed into space with no deflection and the band is really shut.

The point here is that this type of propagation can only extend the openings before and after full refraction takes place. Or possibly when the MUF does not quite reach the band you are working on. What it will not do is cause a band to open when there is no F-layer present. In other words, it is not a magical solution to make QSOs which are otherwise impossible.

So how can I put this information to use? Well, F-layer ionisation is always stronger towards the equator. This is a simple product of geometry. The MUF is usually lower towards to poles (i.e. Scotland does badly of course). So it might be worth trying to work stations towards the equator. Even in Autumn, when the conventional logic is that there is nobody to work on 10m at this time of the cycle, there might be some stations to work. So I tried this briefly on 10m.
10m contacts from GM4FVM early October 2017
I was happy with this result as 10m is not a band I concentrate on. Morocco and Gabon are new countries on 10m for me, and Angola would have been too except that the station was /MM (i.e. maritime mobile) and floating off the coast. Still I am not complaining and I have been hearing stations from South Africa, Brazil and the Falkland Islands too.

There is nothing especially new about North-South paths at this time of year as my results in previous years on JT65 show, but FT8 makes it all easier. Certainly I see contacts on the cluster on FT8 when there are none on SSB, PSK, RTTY and all the less efficient modes, which may also be due to FT8's sudden popularity.

They certainly look like F-layer, as there was no Es at those times and I am too far North for Trans-Equatorial (and so are they).

What annoys me is that when I speak to some local stations about all this they are amazed. "But there is no point going on 10m in the Autumn (or Winter, or Spring, or during Solar Minimum, or any other imagined rule)." In doing this many amateurs are behaving in the manner of those little animals the Lemmings, which are supposed to be so keen to follow their leader that packs of them commit mass suicide in their thousands by following the leader off the cliff top.

I might say first of all that apparently Lemmings do not commit mass suicide. Nor do they follow their leaders in that manner. That apparently is an "urban myth", also known as a falsehood. Apparently they have strong homing instincts and just happen to follow similar paths, so it appears that they are following a leader. This need not concern us too much as we are radio amateurs, not Lemming enthusiasts. It's a good story and lets us stick with what is widely believed just this once. The message of sticking with what is widely believed in this posting is - don't stick with what is widely believed.

In many senses a lot of amateurs seem to be like Lemmings (or at least the imaginary Lemmings which are supposed to blindly follow their leaders). These amateur Lemmings read or hear that there is no point coming on 10m during the sunspot minimum, that Es is caused by the Jet Stream, or that VHF is pointless apart from during the Es summer and two weeks at New Year. Or they believe any other crackpot notion. In fact any other imagined rule that some "bigger man" has made up. And they believe it, without testing the rule for themselves.

These poor folk have been told not to bother, so they don't call CQ. They quickly find that if they do not call CQ then their prediction comes true: nobody calls them. Or even better, they do not bother to turn their radio on at all, which makes us all poorer. For the Lemming Amateur, not turning on the radio is the ultimate proof that there is nobody to work.

It just makes me wonder how not turning on helps anyone.

Lemmings may be daft as a balun, but even Lemmings are curious.

When I write in this blog I try to stick to the observable facts at this QTH. In other words, if it doesn't work here I say so, but that might not be true for you. I hope that you to have a questioning mind, that you are inventive, doubting, and you try things out. I might have something interesting to say or not, but you decide that. Don't just believe me (or anyone else). And it cuts both ways. Don't tell me that I am wrong if it works for me but doesn't work for you. Maybe we are both right. In my experience, one size does not fit all when it comes to radio science.

Don't be a Lemming Amateur. My advice = Check things out yourself.

Check it out. Do not believe that 10m is no good at solar minimum. Give it a go. Or just think about it and maybe work something else out yourself. My Granny Reavey used to ask me "if somebody told me to put my hand in the fire, would I do it?" Of course not. I am not sittin' on the dock of some bay, watchin' the tide roll away. So when somebody tells me that 10m or VHF is useless during the Autumn, I not only try to make up my own mind, I prove them wrong too.

I encourage you not to be a Lemming Amateur. Do not believe "false news", especially false news from the guy who says what you believe already is false news itself. Who is that guy, I wonder? Where does he live?
Autumn Es on 6m has been covered by me before. Such as here and various times before that.

Here are the last 2 weeks on 6m:-
6m Es at GM4FVM in the first two weeks of October 2017
Given that this is the first two weeks in October, and all of it is 50MHz Es, it looks quite contrary to the expectations. Not what you read about in books. However, you will have read it here before. Each of these openings was associated with a small up-tick in the X-Ray levels reaching the Earth from the Sun.
GOES X-Ray flux as shown on Solarham on 5 October 2017
There was another one the next day:-
GOES X-Ray flux as shown on Solarham on 6 October 2017
I could take quite a few other examples. Each time, a small blip upwards, even in just the low energy X-Ray readings, is enough to flip the Es on, and there are useful QSOs to be had on 6m. 9A4ZM and I tried on 4m too, but it was not strong enough at that moment.

Every year I use these transient effects to work Es well into the winter. Perhaps I should just shut up about it. As the Lemming Amateurs have never heard of it, they leave me alone.

Please keep it between the two of us.

Just you and me (and the DX of course).

What I called "geomagnetic disturbance short of an aurora" has a similar effect. Today (14 October) the long but rather weak effects of a Coronal Hole High Speed System (number 34 on the chart) is still having an effect after three days.
CH HSS No 34 seen on Solarham on 9 October 2017
It has produced a nice Es opening into Italy, Fance and Spain on 10m and 6m so far today.
Anyone who thinks that Coronal Holes are only good for auroras needs to think again. They are very good for Es as well, especially towards the end of their activity periods.

Better not tell the Lemmings or they might turn on their radios in October.

I wouldn't want to shock them. The propagation predictions told them it was not worth turning on ... for me it was worth turning on.
I have been busy with the advanced possibilities opened up by FT8. However, without a sked partner somewhere in mainland Europe I have to be content with regularly tripping people's receiving bots, which log my signals into the DX Cluster. It can be a lonely business ,,,
DX Maps on 6m on 12 October 2017
This is just my fantasy here, but I bet that this is not the only path open on 6m in Europe at that time. The Lemmings have decided that October is not a good month for 6m, so they are not around to hear me. Just that one automated bot is there, or others if I beam in other directions. It does get a bit tedious. I know that if there was anyone around who could transmit FT8 I would have a QSO, but there is nobody there.
Just as a quick update, I have got the Messi and Paoloni Hyperflex co-ax installed on the 6m antenna, and I took the chance to re-install the 5 ele 50MHz yagi as a temporary measure (I need the help of 5 elements for this low signal strength FT8 stuff).

I have taken down my 2m and 70cm vertical as most of the amateurs I used to work on that have gone SK of late. There are now only 3 stations active on FM near me, so 4m FM is enough to reach those individuals. I have re-sited the 4m vertical rather lower down, but it makes little difference given the reduced amateur population. I have stopped listening on 2m FM, as there is nobody there. This frees up the Wouxun 950 multiband rig for the car and puts the single band Anytone 588 back in the shack, which seems like the best arrangement.

The 6m stub filter in my 4m line needs attention and I intend to replace it with an LC filter. I mentioned this before when the 4m stub in the 6m line also went intermittent, so it it time to do something. At some stage I also have M&P Hyperflex for the 4m and 2m horizontal antennas.

I am using updated versions of WSJT-X and MSHV, more of which anon. I have also been comparing Pi-RX and MSHV for decoding PI4 beacon mode. No firm conclusions there yet.



Wednesday, 27 September 2017

Some more thoughts on "above the MUF" propagation and the wool cycle

Thanks for the various posts and email which resulted from the last posting.

Leaving aside the obvious clash of meaning - the MUF we refer to here is not the actual maximum but above the calculated value for general use - I decided to have a couple of goes at being heard when there would appear to be no propagation (i.e. I was above the calculated MUF).

There was weak Es on 10m on 25 September, which seemed like a good time to try for the first time. Nobody was working anyone on 10m SSB, at least not in my area and not as reported on the DX cluster. The DX cluster is not a representation of activity but not very accurate - not everybody posts to it. Nevertheless the WSPR traces were rising and falling and there was some solid copy from that excellent reference station IU1DZZ.
10m WSPR at GM4FVM on 25 September
I cannot over emphasise how useful 10m WSPR is for watching VHF. Stations like Gianfranco's provide constant reference marker to monitor the progress of Es. In this case you can see the wavering trace, which lets you know that Es is just, and only just, reaching 10m.

For what it is worth, I try to reciprocate by transmitting on 10m WSPR as often as possible. Not only are the reception reports useful to me, but I cannot rule out the possibility that my signals may be useful to others.

It is worth noting too that there is general tendency for amateurs to listen on the band and if they hear nothing turn off. That is exactly the wrong attitude to WSPR, and it does not help on FT8 now that we know how it can receive unheard signals.

So, moving on to VHF, there were no SSB contacts on the cluster and nothing to hear on the SSB or CW parts of 6m. I turned to FT8 for two hours and worked these stations:-
6m contacts at GM4FVM on 25 September 2017
This was done at a time when there seemed to be little or no activity on SSB. Of course I cannot really be certain about this, as maybe everybody has deserted SSB and gone to FT8. However it is hard to argue that I wrote a piece on 1 September pointing out that my season had ended and I was winding down, only to work this lot on 25 September. So, maybe FT8 is extending my season. And they were not difficult contacts either ...
IZ4IRJ worked on 6m at GM4FVM on 25 September 2017

I must not get carried away either. It is a bit unusual for me to come on 6m on 25 September and actually try for contacts. Looking back through 10 years of logs I see that only in 2012 did I find a decent opening in late September. On that occasion I worked 5 stations in Italy on 70MHz on 22 September. That is fairly unusual, with the latest opening otherwise also being in 2012 when I was working into Czech Republic on 13 September. It is not impossible to imagine a Es opening at any time of the year, but a two hour opening like that was particularly pleasing so late in the year.

I cannot say that I ever really tried for 6m contacts as late as 25 September in previous years. Who knows what the results might have been, but experience suggested that it was pointless.

Anyway, whatever evidence this gave me that FT8 was extending my season, it wasn't enough. Not for me. So I chalked the 25 September event up to weak Es and resolved to try again when there was even less sign of Es.

I tried on 27 September. On this occasion there was no sign of Es on 10m WSPR. The plan this time was different. First I checked that there was almost no sign on Es on the MUF map (more or less anyway, as anyone on FT8 who gets an "above the MUF" contact will show up on the MUF map).
MUF map on DXMaps on 27 September 2017, just one square showing and it was an FT8 contact
Being fairly certain I was above the "MUF", I called CQ on FT8 for 6 minutes each on four likely beam headings. Then I looked to see if I had been heard, by checking the PSK reporter
PSK Reporter record for 6m FT8 reception of GM4FVM over a 30 minute period on 27 Setpember
In the half hour I was heard by 7 stations. I heard no-one and saw nothing on the FT8 waterfall.

So, what does this mean? I feel pretty sure that more than 7 stations received my signals, as not all stations using FT8 activate the PSK reporter service. But for the moment, let us stick with 7 as that should be plenty. Did any of those 7 reply to me, and why did I not seen any trace of them?

In fact this is similar to what I have been noticing since I first mentioned being reported by DK8NE back in June here and also here. Then it was on JT65 (which is slightly more sensitive but hampered by long tx/rx timing), now it is on FT8, but the results are similar. Back then we wondered if could this be ionoscatter or aircraft reflections.

Some other things are similar now too - for instance nobody is calling me back. Or, more accurately, I am not detecting anyone calling me back. Other things are different, for instance these reports came from various beam headings between East and South West, similar to the ones I used to transmit. Is that more likely to be aircraft reflections than the single path to DK8NE was?

The main conundrum remains - whether this is a novel method of propagation or just something we are more familiar with, why am I not having QSOs? When there was a little bit of Es in the background, I did have QSOs (on the 25 September), but then when there was no Es it seemed like "one way communication".

I began to wonder if nobody wanted to talk to me, or if I was doing something wrong. Then it occurred to me that those 7 stations were not working each other either. Nor any other station near me. Nor anybody else. Every so often PSK reporter would report a decoded contact, but no QSOs were reported on the cluster. So could it just be occasional random reception periods - but then again no. I only transmitted for 6 minutes in each direction and most stations reported me within two minutes of starting.

I spent a long time pondering the diagram for "above the MUF" propagation, trying to see if it would be non-symmetrical. Could it produce only one-way contacts? Maybe, but more likely reception would be widely dispersed so a weak signal would be received over a large area. This would also apply to any station who might reply. So, whilst I might not necessarily hear the stations I was seeing who had heard me, I am quite likely to hear any other station who might call. And I heard nothing on 27 September, and saw nothing on my waterfall.

So basically the puzzle from June goes on. My receiver is working as I can work stations during weak Es. Switching between all four rigs produces the same result. I can reach stations on otherwise flat bands, but I am not hearing them. Are they running less power than me? For this purpose I was running 200W, anything less does not seem to work when the band is "closed". Is it possible that no other station in Europe is running that amount of power and beaming at me?

Let me not personalise this, looking at the PSK Reporter and the cluster, it seems to affect everyone who is still on 6m. Have we all worked each other and are sitting on our hands now waiting for something more exotic?

What I think I need is a year-round FT8 sked with a station 600 - 1200 km from here running at least 200W of FT8 into a 3 element yagi (or better). Someone else who likes the sound of silence.
By the way, I am not sure if this is a seasonal thing but the alpacas have been shorn again.
The alpacas at Ayton Law on 27 September (looking like the previous photos but shorn of wool again)
I would have thought that they needed some reasonable covering for Winter. Now that the Es season is over (?) I would have thought that shearing was finished too.

Mrs FVM found some report which claimed that the average UK male spends more time sitting on the toilet than taking exercise. So I have extended my walk to avoid criticism and I have hidden the stop watch in case she tries timing me again. Timing me on the walk that is. My pedometer says it is 10,000 steps and generally it takes about an hour. Thus the walking route passes the alpacas and they do make a very odd noise. Rather like a grunt, but at least they do reply. Decoding it is not easy either.

Anyway, I thought alpacas were only shorn once per year.

I am listening tonight for an aurora. Maybe that only happens once a year too.



Thursday, 21 September 2017

8 Sept aurora and "above the MUF" propagation with FT8, JT9 and JT65

Olli, DQ8BHA, whose blog is listed on the sidebar, writes some very interesting material. His description of the 8 September aurora is worth reading (remember to use the back arrow to return here!).

Thanks to David, GM4JJJ, for alerting me to an article by Carl, K9LA, in October 2017 QST magazine entitled "Understanding Propagation with JT65, JT9 and FT8".

This article brought me to one of those "D'oh!" moments. Suddenly things which should have been obvious fit into place and I realise that I should have worked this out myself.

The article explains that the ability of the slow WSJT-X modes to receive signals "below the noise level" means that we can work stations using these modes when the bands are closed. Now that was sweeping statement by me. SOMETIMES. Let us think about why this can happen.

It is well know that these modes (and WSPR) can successfully decode signals which are below the level of noise in our receivers. In fact, so can good CW operators using their ears. The seemingly odd outcome arises both from the fact that the superb modes devised by Joe Taylor and his merry band can makes sense of extremely weak signals in this nether region, but also the way we define noise is rather arbitrary.

When your WSJT-X software shows that you have decoded a signal at -20dB, that relates to the noise factor for the SSB filter, and in reality it is not 20dB below what you can hear. However, make no mistake, it is a lot below what you can hear, just not quite 20dB. Let us take, for the sake of argument 10dB below what you can hear. Imagine that. Think of a signal that needs to be 10 times louder for you even to hear it, and then imagine decoding the weak version. Pretty impressive.

The fact is that the minimum signal to noise ratio required for reception of SSB is higher than that required for CW, which in turn is higher than that required for, say, JT65.

You may think of it this way. You are working a nice distant dx station just as the band closes as the MUF falls. In other words, rather than being below the "maximum usable frequency" (MUF), you now find yourself operating above the MUF. Whilst on SSB the signal would have faded into the noise, and you can no longer hear it on the loudspeaker, on FT8 or JT9 you are still about to complete the QSO. Magic. Except that it happens all the time if you use FT8 or JT9 (or JT65 or WSPR). You just keep completing QSOs where you cannot hear the other station in your loudspeaker.

However, there is another way to look at this. For an SSB operator the band has closed. They cannot make a QSO as the MUF has fallen and "the band has closed". But you, as a data mode operator can still work people. What you are doing is using what is called "above the MUF" propagation.

In effect, using these data modes has made an otherwise closed band stay open for longer.

Let us have yet another take on this. When I started on data modes back in the 1970s I used RTTY. I might be appalled by that mode these days, but it was cutting edge then when nobody had a PC. RTTY was (should be past tense) a mode which basically replaced the microphone with a bulky, oil-spewing, unreliable, clattering electro-mechanical beast. You did not get any extra performance out of this contraption, it just meant that your QSO got printed out instead of spoken. Unlike RTTY, WSJT-X slow modes are not just a text-based replacement for voice or CW. They out-perform SSB by being able to be used successfully in conditions where phone, RTTY and CW would not work at all.

In the 1970s, during any opening, my RTTY success directly mirrored by SSB success. If the band was "open" I could use SSB or RTTY. If the band was "closed" then both stopped working. But the WSJT-X slow modes continue to work. So how does that happen? Surely the F-layer (or the E-layer) is either bending the signals back to earth, or it isn't. How can using different mode make a band open?

Let us go back to basics. The diagrams are my own (copyright!) handiwork, not to scale and can be enlarged by clicking on them. The QST article is based on 28MHz and F-layer propagation, but there is no reason why the same principles would not apply to other bands or E-layer propagation. For this purpose though I will stick to the same example as the article.

When the band is "open" the ionosphere bends (some of) the signal back down to Earth in the well known way. The classic diagram shows band open ...

... (above) where you would expect to find propagation between A and B, and (below) closed, when you would expect nothing to happen between A and B ...
If this was all there was to it, everything would be as we expect. But once again the simplistic diagrams we all used to learn radio theory let us down.

The diagrams above show the F-layer as if it is a thin line which either reflects (band open) or refracts (band closed) the radio signal. In reality we would have no propagation at all if that was the case. The F-layer could never reflect radio signals at the angles we transmit them. The F-layer is not a mirror, it is a layer of ionised gas which has a structure of steadily varying density. This variation in density results in a very large number of small refractions of the signal, gradually bending it down until it is almost horizontal, and only at that angle is there one, small, reflection which returns the signal via a whole series more of refractions.

So almost all the work of returning our signals to Earth is done by a large number of refractions. Let us look at a diagram of how the F-layer would look - and this is definitely not to scale - when the band is open ...
The signal follows the green line inside the F-layer. It starts to bend as soon as it enters the F-layer, refracted by the changing density it passes through. It is almost as though the F-layer was made up of a series of very thin layers on top of each other, each with a different density.

What nobody told us in radio school was that every time one of those refractions takes place, there is also a reflection. This has been known for hundreds of years in optics, and light is just a different wavelength of electro-magnetic energy from radio, so the same principles apply. The Fresnel equations can calculate the relative strengths of the reflection and the refraction. The other basic optical principles apply too - so the angle of the diffraction will depend on the relative difference in density, but the angle of the reflection will still be the same as the angle of incidence. Which means that actually we get something like this ...
Why did nobody tell us about this? In the real world of radio the many reflections are small in relation to the strength of the eventual main signal. Not only are they low in relative strength, they are directed slightly differently and sometimes out of phase. So  in the world of 20 metre band SSB you often never notice them. They do reach Earth, but they are weak enough to have been considered irrelevant.

In fact, given the noise handling ability of your radio you might never hear them. But JT65 can.

And JT9, FT8 and WSPR can hear them too. WSJT-X slow modes can successfully decode signals well below what we can hear. You might correctly take that to mean that they can hear weaker stations when the band is open, but it can also mean you can work stations when otherwise the band is closed and you can hear nothing but noise on the loudspeaker.

Moving on from the time the band is open until when it is closed we would get this diagram for the ionosphere ...
This is what we knew: it explains why we hear nothing when the band is closed. But the weaker reflected signals are still directed towards Earth, as shown below...

These weaker signals will pass through the F-layer, though they may be bent a bit in the process, and some will reach the ground. If they are WSJT-X slow modes they can be detected down to much lower levels than would be possible for voice signals.

The result of this is that before the bands open, and after they close, the weak signal modes should be able to decode signals we cannot hear above the noise. We need to re-think our existing assumptions. Most MUF predictions are made on the basis of a conventional SSB radio with about 100W and a dipole or small beam. The QST article suggests that a path of almost 3,000km, a single F-layer hop, would be open for an SSB contact at 28MHz (obviously) with the MUF of 28MHz. In fact this could be done on low power, with 100mW of CW doing the trick. But of course once the MUF falls below 28MHz this path is lost and the band is considered to be closed.

The article goes on to suggest that CW using a narrow filter could keep the path open at 28MHz at 10W even if the MUF falls to 25MHz. So, operators are already using "above the MUF" propagation. However, using FT8, JT65 or JT9  this path would be open with the MUF of around 23MHz. So the ten metre band would sound dead, SSB would be possible on fifteen metres, but data operators could operate on the otherwise "closed" ten metres. CW operators might get away with the WARC band on twelve metres.

The significance of this is that the MUF rises to 23 MHz far more often than it reaches 28MHz.

The fact that WSJT-X data operators are making stacks of contacts when the band is open is already clearly demonstrated. But this other fact shows what some of us had already noticed - these modes can make contacts possible on an otherwise "closed" band.

It could be said that there is confusion over our own figure "maximum usable frequency". For practical reasons we have set this figure by taking the measured critical frequency using near vertical incidence reflections and multiplying it by a constant which produces a figure which works for SSB and the receivers we all normally use. However, the better sensitivity of these WSJT-X modes alters the constant to be applied. What we call "MUF" is really the "Maximum workable frequency for easy SSB contacts".

In a sense it is silly to talk about "above the MUF" contacts as F-layer propagation should be impossible above the MUF by definition if it is really the maximum usable frequency. However, I bet that the term MUF will continue in use to mean the frequency at which those easy F-layer QSOs start happening.

I avoid the easy contacts and go for the difficult ones. But you knew that already.

So what happens if the MUF is much lower, and the F-layer basically disappears? Does this "above the MUF" propagation disappear? Not totally. At that point although reflection more or less stops, even at a very low level, scattering from the atmospheric molecules will still occur and produce just the sort of weak signals which JT modes love. Ionoscatter has been known for years too, but it usually requires high power as it produces weak signals - something which JT modes are ready to help with.

I should have seen this coming. I knew that these modes can receive much weaker signals than the human ear. What I had not thought about was that they could in effect outwit the conventional calculation of "maximum" usable frequency. None of this is new - Isaac Newton (1642-?1726) knew about reflections during refraction in light. The people who made my camera or my glasses spend a lot of time trying to minimise the effect by applying coatings to the lenses. However, our radio educators thought fit not to remind us about it. As so often, the standard diagram in the radio text books is over simplified. Oh yes, it was over simplified on this blog too ... mea culpa.

When I started using WSPR I told some old timers about the results I was getting. Their immediate reaction was that it is was impossible and somehow WSPR must be using the internet rather than radio. When I assured them that WSPR was all radio over the whole route from my antenna to the other station's antenna they were very sceptical. Now I know what was happening. More recently as WSJT-X modes became more popular on 6m, several of us have been finding paths open when the band is otherwise "closed".

As always, more investigation is required.

This is my stumbling attempt to explain this. I encourage you to look up the much clearer explanation by K9LA in QST if you can. I hope to put it to more use soon.

And thanks again to GM4JJJ for putting me on to this. It explains a lot of what I have been experiencing but not understanding.

I wonder how often stations turn on, listen to the band, hear nothing, and switch off. What would happen if they tried calling CQ on FT8?



Thursday, 14 September 2017

Did I miss an aurora?

I have been in Blankenberge which, as is well known, is in Belgium. It is customary in this blog to show the means of transport I used at the end of my trip (how did that come about?). Anyway here is a tram at De Panne, which was as far as we got before heading back to Blankenberge...
Tram at De Panne 09 September 2017
We did use trains which were more comfortable and rather faster to reach Belgium in the first instance.

The journey back from De Panne was, at 115 minutes, the longest time I have ever travelled in one tram. We broke the journey on the way out, but as we were tired on the return we decided to do the whole thing in one trip. Result - seriously numb bums. Almost as bad as the plastic seats on Euskotren from Bilbao to Irun via Donostia.

Anyway, it was clear to me that all my recent talk of the "end of season wind-down", and me decamping to Belgium, doesn't stop auroras happening. If I learned anything in statistics class (did I learn anything in statistics class?) it was that anything with a distinct probability, however small the probability, will happen sometime if you wait long enough. Like motorcycle accidents and unexpected pregnancies, if the basic requirements keep being met, then eventually even an unlikely outcome will occur, given enough time. So we shouldn't be surprised, and that also explains the scars on my leg, my broken upper jaw, and other things like me being here in the first place.

I have gone on about this before. The "Carrington Event", the most violent solar storm seen and recorded (so far), occurred in 1859. When I was at school we were told it was a "once in a hundred years" event, so we have better expect it soon. Now we are told that it was a "once in 400 years" event. We shall see. "Once in a hundred years" floods seem fairly common these days.

The aurora on 8 September was a good one. Not in the Carrington Event category, as one of those would threaten power systems and satellite communications, but good all the same. As we have not had a good aurora for some time, and as I missed it (boooh-hoooh), I am lucky to be able to draw on the reports of others to describe what it was like. Mike, GM3PPE is about 30km South West of me in IO85, David GM4JJJ is about 90km North-West of me in IO86, and both gave me accounts of the event. Thank you to both of them for allowing me to quote from their reports.

The basic plan for aurora is to be on alert for anything untoward happening. Mike was able to send me this email on 6 September which was very accurate in predicting the events of the 8th.
"I was on 15 meters this morning working stations on FT8 when suddenly at 0910Z all signals disappeared.  The same on the other HF bands.  I thought my rig had broken, or the antenna fallen down!  Then 30 minutes later all signals back.  A massive event on the sun.  Middle of the day another total radio blackout.  Apparently the biggest solar X class solar flare for several years.  It looks like there was an accompanying CME in our direction, which augurs well for a big Au event over the next 24 to 36 hours."

After the aurora Mike sent this report "6 meters started buzzing at lunchtime and closed to Au contacts mid evening. Kp went up to 7 and the geomagnetic records went purple.  I have never seen that happen with previous events.

I worked about 40 stations all over the UK and Europe, with some even on SSB.  Signals were very strong with some peaking 59A on my K3.  Towards the end of the event some signals start going Es, with hardly any Au buzz at all.  LA8HGA was particularly noticeable for this effect."
" ... the Au opening ended quite abruptly for me at about 1830Z - as you say, quite early.  In terms of DXCC countries, I worked G, GM, GW, EI, ON, LY, SM, F, DJ, PA and LA, making a total of 21 squares.  Not a bad haul for one day on 6 meters!"
Quite right Mike, and well done on that. 21 squares on 6m is remarkable and once again it proves what can be done on VHF.

SSB can be useful during auroras, even if the distortion makes it difficult to use voice. There is a large band of amateurs who never use CW, and during an aurora they can only be reached on phone. If I need the square I can use almost any mode I need to, however difficult that might be.

Mike sent me a link to the British Geological Survey site:-

This certainly shows the 8 August event in context (and shows the purple bar graph which was a new one on me too) ...
BGS "Current Geomagnetic Activity" chart for Lerwick taken on 14 September 2017
Click to enlarge if necessary (as always).

Note too that geomagnetic activity had another smaller peak later in the week and there may be some more action to come. The fact that you often see possible warnings of auroral events when nothing actually appears is part of the joy and the frustration of the hobby. This time who knows?

David, GM4JJJ sent me these useful illustrations of his operations:- 

2m Aurora Map showing worked squares with 500km intervals in red

4m Aurora showing worked squares with 500 km intervals in red

OH SLICE meteor Radar showing the solar flare attenuation at 36.9 MHz on the day before Aurora at around Noon. 

Thanks and congratulations David, well done.

It takes a fair amount of determination to work stations on 2m during an aurora. The Doppler shift is greater as the frequency increases. This makes life harder.

Clearly 8 August 2017 was a "big" aurora in every way. 

I am sorry I missed it. I used to work in Belgium and I always enjoy practising my rusty Vlaams (and indeed Dutch and French, if I can admit to that too). 

En waarom niet? Een fles Kwak voor GM4FVM!

Thanks for all the information and let us see if there is another aurora round the corner.



Friday, 1 September 2017

31 August Es and the end of the season wind down

Here, as I gaze over my estates from the lofty heights of the old stone tower at the end of the West Wing, I see the workers toiling in the fields to save the wheat crop ...
Harvesting the wheat as seen from GM4FVM's QTH on 27 August 2017
Actually, there does not seem to be too much toil involved sitting up there in the cab of the harvester watching the machinery doing its work.

If I really did have a West Wing with a stone tower on it, I would have attached another antenna to it long before now. Especially if it had lofty heights.

No, this week I have been watching the field behind the house being sucked clean of all its produce, then straw baling being completed. The straw bales have already been removed and no doubt ploughing and drilling will be complete within days. Who knows what crop will be pushing up next year?

When it comes to harvest time I start thinking of Autumn, and the end of the Es season. Time for me to review the Summer and then batten down the hatches for Winter.

This year I feel that I have overdone things over the Summer. I think that it is time for a break from operating and use the opportunity to spend a bit more time with my other projects.

Most of my amateur radio life has been marked by upsurges and downswings in activity. I am not an operator with just a rig and a bit of wire, but nor am I someone who invests all his time and money in this hobby. I move around the middle ground, sometimes getting too much involved and having to step back a bit. So this is time for a step back.

The Es season is over, the Christmas VHF Contests are over the horizon. Time for a measured reaction. The Autumn promises more Es, more aurora, more meteor scatter, and more tropo. So bring it on, as I am not going hunting for it.
 31 August produced a nice Es opening.

I knew it was coming towards the end of the week because the RSGB VHF propagation report said there wasn't going to be one then, but "at the head of the week" and it would "struggle" due to "weak Jet Streams".

So, of course with this promise I reckoned that if they say it will happen weakly at the beginning of the week I should start looking for a strong one at the end of the week. I find that is the best way of treating these reports, and it has always worked for me.

I am not saying that Jet Streams have nothing to do with Es (though that is what I think, but it is hard to prove a negative), but what I can say with fair certainty is that using them for prediction does not work. Relying on the predicted Jet Stream to base an Es prediction is always wrong here.

Jet Streams might be implicated in Es (I doubt it) but if this is the track record of making predictions based on them, what I have seen over the last year or so makes the predictions look laughable.
Es as reported by DXMaps at 21:18 on 31 August 2017.
I had a number of nice contacts, including I6FLD, IK4ISR, IZ8IBC, SP7QJF and SP8NR on 50MHz, and returning regulars DD3SP and OK2BRD on 70MHz.

Actually Sandro, DD3SP was an interesting one on 4m as I worked him first with meteor scatter on MSK144 at 13:16. I guessed that would be my last German station on 4m for this year, as their temporary authorisation ended on 31 August. But then I worked him again on SSB on Es at 20:32. I also worked Jiri, OK2BRD twice, both on Es. First by FT8 at  20:37, then again on SSB at 20:45.

It is notable that the last QSO was at 22:55 and I only stopped because I needed some sleep. This bout of Es was generated by a geomagnetic storm caused by a coronal hole. There was no widespread aurora, though I did hear the usual Northern Ireland beacons over the previous day or so. I often see this Es pattern repeat itself during positive polarity coronal hole disturbances. Perhaps today we will get some negative polarity material from the Sun too, and maybe an aurora.

10m Es was pretty good as well...
10m Es on WSPR, 31/8/17. Presumably Mauritius was F layer, but you never know!

A great day of Es to round off the season, so to speak. I will miss the German stations on 70MHz even though, due to conditions, they have not been as prevalent as previous years. I already miss Italian stations who we have not heard on 4m for several years.
It definitely has been a busy Summer and I am in need of a bit of a break. Never mind the radio, a brilliant Tour de France (Rigobero Uran was brilliant) was star of the season. Now the battling of Contador, Nibali and Aru are keeping me welded to the television and La Vuelta Ciclista a Espana. Not just cycling, but cricket has been superb too, plus of course Masterchef Australia. What a Summer.

I am not going QRT, just taking a bit easier. There is plenty more for this blog, or so I hope anyway.




Sunday, 27 August 2017

2017 Es season - not that bad? Aurora springs to the rescue.

I wrote this over the past few days. It started off being a piece complaining about poor Sporadic E conditions. As the piece developed, it turned out that things were not as bad as they had seemed.

What was bugging me was that on the 70MHz band (4 metre band), I had only had one Es QSO so far in August. Normally I would have had many more, and I can often work up to 8 DXCC in August, whereas of course in 2017 it was just one. I moaned about this in my last posting, and I went off and got the figures out of the logs to prove it.

Of course, it was probably just random variation (and not the weather and definitely not the jet stream). As I was finishing off my blog there was a small opening on 4m. I worked two stations in 4m, both in EA. One was on SSB and the other on FT8. That was followed the next day by a short opening into OH with two stations worked. For a while, the OIRT interference made it look like the "good old days" of Radio Gdansk...
OIRT broadcast stations at GM4FVM on 27 August 2017

So I have decided to re-write my downbeat piece as a review of the good things that have happened recently. And why not?

I can hardly complain about the 2017 Es season as a whole, even if August has been relatively poor. Six trans-Atlantic contacts on six metres on six different days so far this year. These cross Atlantic paths are (we believe) multiple hop Sporadic E. Ron, WB3LHD, went so far as to send a very striking QSL card direct ...
QSL Card received direct from Ron for 6m FT8 QSO on 29 July 2017
We do have sea eagles not far from here, plus kites and buzzards overhead, but that is quite a bird. Even the slightest squeak from any large bird sends Katy out of the garden and into the shack for shelter, so I have kept Ron's card out of her very sharp cat vision.

However, none of those NA QSOs were in August.

I suppose in this respect I am "old school". I really like receiving an unexpected QSL card through the post. After I sent the card back (direct) Ron sent me a screenshot of what the QSO looked like from his end. Unfortunately I did not take a screenshot at my end.

Nor can I complain about working 7K2KF in Algeria recently. I view this as a new continent. Sure, I have worked Madeira and the Canary Islands on 6m, which count as Africa, and had many 2-way spots with CN8LI on WSPR, but I have never before had an actual QSO with a station on the African continental mainland itself.
7K2KF on 6m at GM4FVM on 25 August 2017
I am not sure why this has taken me so long as the CN8LI spots prove that the path is open quite often. 2162km to 7X2KF is not far in 6m terms. It seems that the "FVM equations" are the problem, with Egypt, Tunisia, Libya, Algeria and Morocco all within easy range but not very active. The issue here is not about the level of Es, but more about the level of activity. Or so I suspect.

It also depends how the weekends fall in the month. Conditions are always better at the weekend. Of course, this is not true, but it seems to be. There are more stations around, they make more noise when the bands open, and that gets others involved.

I have also had a few QSOs into France - which is a great place for me to find new squares on 6m. France was late to release the 6m band, and then at first only part was opened up. Now it is easy to work French stations but they are still few and far between. Given the size of France, just about everybody starting up is in a new square for me.

However good things have been on 6m, 4m has not been good for weeks. I have to conclude that it is probably just normal statistical variation. Up here at 56 degrees North I am towards the edge of the strong Es. Stations in the Mediterranean get much more, and the further North you go the less we benefit from it. So it might reach us here on 6m, but the ionisation might just be too weak to work at 4m from here. A few days like that and it makes all the difference.
If Es levels may be down (and reading the above, they probably are not down), auroral activity is definitely down.

I wrote a long piece about auroras to illustrate them, but I still have not posted it.

There were more auroras over the last couple of years, and fewer recently. ("Please, no more figures Jim", they cry). That is probably due to the well established pattern the auroras peak in the two years after a sunspot maximum.

Like meteors, auroras do not go away just because it is not a maximum period for them. The various sites suggested that a coronal hole might have been active for the previous two days, but nothing exciting was predicted for 23 August. Suddenly my 10m WSPR monitor showed a blast of noise which filled the waterfall right across the screen. It must have been fairly wideband but I did not see it on the higher bands...
Wideband noise burst on 10m before the aurora on 23 August 2017
This was followed by me hearing the beacons on 2m in Northern Ireland, plus the 4m beacons on  Syke and in Northern Ireland. Interestingly the 4m NI beacon is now running PI-RX mode and I could compare the signal direct and via aurora, depending on which way I turned my beam antenna.
GB3CFG beacon near Carrickfergus while beaming directly at it (tropo)
GB3CFG beacon while beaming North (aurora). PI-RX is decoding despite the Doppler distortion
I must say something more soon on this blog about PI-RX beacons. Let us say now that unlike almost every other data mode, PI-RX works during an aurora. Looking at the comparison above, between direct and via aurora, it is amazing that PI-RX can make anything out of it at all.

Beacons were all very well, but what actual stations could I hear. As usual, not many.

I managed to work one station each on 4m and 6m. They were both LA9BM. Leif and I seem to find ourselves in this position quite often - the band is open but there is nobody else to work. Not quite though, he worked a few more, including OH0CO. I had heard OH0CO over the past few days via meteor scatter but he did not hear me, and I did not hear him on aurora. Aland Island would have been a new DXCC on 4m and 6m, but not a new square.

Anyway, I worked LA9BM on 4m and 6m using CW, and not even using my pre-programmed QSOs using the keyer memory. All done old style with a keyer and brain power. I did hear a couple of other stations but their CW was far too fast for me to try to work. Why does anyone use fast CW during an aurora when signals can be distorted and hard to copy?

I like a good aurora. Even if I only got to work one station on two bands, this one was better than nothing.



Monday, 21 August 2017

MSK144 and The Perseids

Well, the Perseid meteor shower has been and gone for this year.

After I wrote the eleven points about MSK144 and the Perseids David, GM4JJJ added another. I will re-post it here:-

Might I add a number 12 bulletin point?

In MSK144 there is a checkbox marked 'sh'. This allows a short-format message format to be used.

The user guide explains:
For operation at 144 MHz or above you may find it helpful to use short-format Sh messages for Tx3, Tx4, and Tx5. These messages are 20 ms long, compared with 72 ms for full-length MSK144 messages.

It also makes plain that on 50 and 70 MHz sh is not useful as the pings are of much longer duration anyway.

What is important to remember is that on 144MHz, you need to know if the other station is using sh or not, failure to use the sh setting if he is using sh will result in no decode even when a strong burst is received.

Another point is that if sh is used, there is a greater chance of false decides, so once you have detected the other station it is best to use RIT to get your RX frequency as close to his transmitter frequency as you can and then narrow FTol.

Thanks for that David.
"Sh" is accessible by clicking a box. SWL mode is for listening to the Sh messages of others

I might even add point number 13.

13) Think about AGC?
On the face of it, AGC should be turned off, especially on 2m metres. Meteor scatter pings are short events and they tend to be shorter the higher you go in frequency. AGC will cut your receiver gain as soon as a ping is detected, and therefore seems like a bad idea for a mode which depends on momentary signals. You receiver gain may remain lowered as the ping trails off, and thus you might miss the weakest part of a vital ping.

In practise I find that this is not an easy decision to make. Using my IC-7100 and IC-7300 the initial AGC action is very deep. However, the recovery time is adjustable and you can make it very fast indeed. At the fastest setting the response is good and it seems to help in some cases.

I would therefore suggest that it might be a good idea to try the AGC on and off for trial periods. To some extent it will depend on your rig. Slow acting AGC is almost certain to be detrimental, but fast AGC might work depending on the equipment. If in doubt, I would suggest turning it off.
I am a bit worried that listing 13 points makes meteor scatter with MSK144 look very difficult. It is not difficult. Why not try it and see?
Just because the Perseids are over, there is no need to wait for another shower to try meteor scatter propagation.

About 40,000,000 kg of material collides with the Earth every year. Whilst during a shower the particles may be bigger and there may be more of them, this is still only about 4 times the average for a normal day. When I say bigger, maybe golf ball sized, rather than the size of your thumb nail or smaller. But even a speck of dust can produce an ion trail as it falls to Earth and compresses the atmosphere in front of it, producing heat, light and ionisation as it progresses. Either the "burned up" particle is reduced to a speck of material which falls gently through the lower atmosphere, or, more likey for the ones that interest us, they are vapourised entirely by the intense heat.

Any object large enough to remain a significant size and reach the Earth's surface is called a meteorite. If we are ever going to be on the receiving end of a large meteorite then, believe me, the effects it might have on radio propagation will the be the last thing we are interested in. So the small ones are our main interest, and they fall all year round.

Is random meteor scatter a reliable method of communication? Take my QSOs with Henning, OZ1JXY. Since 2014 I have worked Henning by meteor scatter 61 times, at all times of the year and at all times of the day. That is reliable meteor scatter communication over a fairly short distance - 732km. During the same period I have worked Henning only two times on Es and once each on aurora and tropo. Anyone who suggests that meteor scatter is confined to a few days of the year needs to look at the performance of that link (not even a sked, all of it random answers to CQ calls).
OZ1JXY blasting in on FSK441 on 1 October 2016, outside a recognised meteor shower

There is enough "stuff" falling into the atmosphere, be it space dust from far-off stars, emanations from the Sun, space debris, or whatever, to keep a good QSO going all year round (though in February the going gets tough).

The Perseids shower is formed by the Earth crossing the dust trail left behind by a previous pass of the Swift-Tuttle comet. As we pass through the path of the comet we cross the material it left behind. Thus we have a predictable event to take into account. Random meteor trails are not as dense, but they are capable of producing surprising results for the amateur. And they occur almost all the time if you have the patience to wait.
Given the many advantages of MSK144 over previous formats, I am surprised to see so many stations on 2m still using FSK441. I will not go into the reasons for this, but they are just plain stupid. The justification used by one or two of these people is keeping MSK144 off the table for the rest of us.

For many operators, all they do is follow the pack, which in this case means sticking with FSK441. Nevertheless, for the few operators who drive this piece of numb-skullery, the basic object of resisting the spread of MSK441 is their belief that changing mode will damage their success. It won't.

There is a sort of meteor scatter neurosis which develops amongst operators. I know, I have had it too. The other station seems never to have heard you, though you can hear them (or vice versa, it doesn't really matter which). Therefore, the fault is clearly your antenna, their antenna, the software, your sound card, the phase of the Moon, ..., perhaps this new mode will reduce my QSO potency. This is human nature, given the characteristics of a mode that depends on tiny wisps of signal. But, meteor scatter communication depends on probability. You are waiting for a randomly timed event to happen. The gaps between hearing the other station are --- random. Who'd have guessed it? There is no need to blame your rig, or MSK144 for it, nor anything else. Mind you, when you are sitting there waiting for a signal, you might think of everything under the Sun.
Here the Perseids produced a few interesting contacts here.

6m MSK144 - LX1JX, S59A, SM6A, and SO3Z
4m MSK144 - DF1AN, DF3XZ, DF5VAE, DJ9YE, DK5YA, DK6AO, DL4KUG, DL9YEB, GD0TEP, OH7TE, ON4FI, OK1DIG, OZ1JXY (of course - twice), OZ1MFP, OZ6GH, PA3ECU and YL2CP,
2m FSK144 - SM2CEW and SM7THS

With 6m squares now being less sought after by me (I already have quite a lot), I have been looking for new ones and not calling ones I have. On the other hand, most of the 4m contacts were from stations hunting out my square, IO85. I do not think that I live in a rare square on 6m, especially as it has Edinburgh City in it. However, on 4m there are not many active operators, hence it is more in demand.

With 2m I stood out for a while by sticking to MSK and working no-one as a result. I had a few QSOs on FSK but that was it.

Two new countries for me were provided by LX1JX on 6m and YL2CP on 4m. Many years ago Jack, LX1JX (JO30, 843km) was my first LX station on 4m (on FM!) but it has taken a while to track him down on 6m. YL2CP (KO27, 1674km) had to have a lot of patience to work me as we had a number of attempts over two days. Because YL have only recently gained 4m he was much in demand and had to keep switching to other stations who kept calling him. We did it in the end though.
All this talk of meteor scatter has made me think about how reliable it is, and how unreliable Es has been for me this year. I must look all that up and see if I am imagining it.