Sunday, 3 December 2017

Using aurora warnings to predict Es, and more on noise reduction.

November is another time of the year when, in addition to nice meteor scatter contacts, I can find Es openings by using the data available for aurora watchers.

There is nothing especially new about this, I do it every year. The first step in the process is to forget the constant barrage from amateurs who have "found the link" between Es and the weather, the sea temperature, Alpine lightening and so forth, and return to the more generally accepted view that the ionosphere is affected principally by events on the Sun. Particles (and radiation) from the Sun have a major influence on the ionosphere.

I hasten to point out that the weather does have some influence on Es, as to some extent wind shear is a factor. But none of the theories put forward so far seems to work for me in a predictive sense. I can do without theories which look backwards and explain how the events occur after they have happened. This is interesting but not very helpful when you are trying to fit radio into your already busy life. I like something that tells me when something is likely to happen (in the future!).

When there are strong events on the Sun this often produces auroral propagation here, and I enjoy that. But less powerful events also make for nice Es which most people miss. At one time I just stayed tuned to 144MHz and listened for aurora, now I enjoy contacts on 10m and 6m Es while waiting for any possible aurora. Often there is no aurora here anyway. So my time is not wasted.

November produced a few of these events, as it often does. It is not helpful to look at sunspot activity as a predictor here. There is some vague link - auroral activity is said to peak two years or so after a "solar maximum". Fortunately for mankind the Sun is always active and many very good events can occur at any stage of the solar cycle. There are mini-eruptions, and a huge variety of disturbances and small irregularities on the Sun which have an affect here.

So I look for raised solar wind speed predictions. The polarity of the arriving material seems to have little influence. Some very nice Es openings have occurred when the "Bz component" (an element of the Solar wind's three-dimensional magnetic fields which tends to encourage radio auroras when negative) is either positive or negative. Sometimes I wonder if positive Bz is not better for Es and worse for radio aurora, but I have no strong evidence to make a conclusion about that.

Anyway, enough waffle, what happened? After rambling in my last post on 24 November I decided to try out 6m Es. I could see that "space weather" was disturbed, with high solar wind speed. The "normal state" for the GOES low energy Xray flux level (the lower blue graph) is so low that it often disappears off the bottom of the logarithmic chart. However, in the period 22 to 24 November it was high and variable. This is the sort of thing which makes me look for Es ...
GOES Xray flux levels as shown on Solarham, period 22 - 25 November 2017
I was getting good results on 10m WSPR ...
10m WPSR spots at GM4FVM 24 November 2017.
So I reckoned that the best propagation would be to the South, given the 10m results and the fact that what solar energy there is at this time of year is concentrated towards the equator. Any slight improvement to that background ionisation by the raised Xray levels and solar wind might cause a 6m opening.

At 13:30 I worked EA5/G3XGS on 6m using FT8.
This was the only contact I had but it proved that the aurora warning was fairly effective in predicting Es. Not every contact is reported on DX Maps and no doubt if there had been other stations operational on the generally North/South axis I might have worked more.

The 10m opening continued for another hour or so.

These openings are frequently weak and often short, but they do prove that there is life on 10m, and sometimes even 6m, outside the enthusiastically supported Summer season.

With another warning of possible auroral activity on 1 and 2 December I tried again. The event proved to be too weak for auroral work here, with the wind speed over 400 but less than 500, and the Bz negative but in the range 2 to 5.
Solarham data 1 December 2017
Just the formula for Winter Es 10m action ...
10m WPSR spots at GM4FVM on 1 December 2017

Nothing got high enough to worry anybody on 6m Es, and anyway, most 6m activity has switched to MSK144 for meteor scatter events (which is another subject, but covered in my last posting). Still, on 2 December the 10m event continued.
10m WPSR spots at GM4FVM on 2 December 2017
Maybe not as productive as the day before, but still hardly "the band is closed" as many think.

Sometimes I think that non-auroral events give me more fun that the full-blown ion-stripping magnetic blast of the Northern Lights at their most majestic. Anyway, a big event which causes auroral propagation often produces Es as it gets weaker, which all seems to be the same mechanism to me.

Anyway, more solar fireworks are predicted for around 4 January (possibility of Au and Es) due to several coronal holes, and this is a period which could coincide with raised barometric pressure (possibility of tropo) and a combination of weak patterns of meteor shower activity (possibility of meteor propagation). We shall see if this grand conjunction comes to anything, but a bit of 10m Es would satisfy me; anything more is a bonus.
Coronal Holes as detailed by Solarham on 2 December - effects expected around 4 December

I have talked to couple of amateurs who have complained about man-made radio noise in their localities, but when I asked them if they had checked their own noise generation they replied that they had not.

It is very easy to blame everyone around you without checking your own contribution.

When it comes to noise the Inverse Square Law is our friend. Anything twice the distance from me is one quarter of the power here. So anything generated "down the street" is likely to be weak. But the converse applies - anything generated in our own home is likely to be very strong indeed.

As with so many pet subjects, I have been banging on about this for years. The thing is, the task is never-ending. I can blame Mrs FVM's laptop. The power supply is surrounded by ferrites but the thing radiates directly. The upside of this is that Mrs FVM is more likely to respond to a request to turn the thing off than my neighbours.

I recently bought a new laptop myself. It has an i5 processor and a large quantity of nice fast RAM. Well it is not exactly new. It was second hand from eBay, quite a bit less than £150, and it came without a power supply. Bargains like this often come from company liquidations, one-off exercises and the like. I myself was involved with a one-off project where 1500 people were loaned lap tops for a three month period. The computers were then collected back up and appeared on the "almost new" market. Mine has a slight screen defect, but it was much less than a quarter of the new price.

Anyway, I also ordered a branded "original" power supply from an unknown site on eBay. In the past I have ordered these and they turned out to be unbranded copies which poured out interference, but the seller had always mysteriously disappeared when I tried to complain. This time it didn't even turn up and I got a refund. I run the "new" laptop on a multi voltage, multi plug general purpose PSU which make almost no noise. Anyway, the one that I had refunded turned up weeks later. Although it is branded it make a dreadful racket. Is it a fake? Who knows.

This story just reinforces my thoughts that you cannot expect to be noise-free. My own computers and screen make some noise and I try to minimise that. My central heating boiler makes a noise on 10m which affects the received signal on my FT-817 but not on my IC-7100. If you look at the design of various rigs some will be more inclined to suffer from noise than others, and as usual the degree of linearity will play a part (in both the susceptibility to noise and the price of the rig).

Noise is unavoidable but it is not incapable of being reduced. Regular readers will have read about my efforts with LED versus fluorescent lights, BT modems versus generic brands, cooker hood power supplies, USB leads of all sorts ... the process never ends. Nor should it. New devices appear in the FVM household regularly and there is always a dB or two to save. I don't automatically blame the neighbours because experience has shown me that the latest noise is ALMOST ALWAYS arising from within the FVM demesne.

For a while I have been wrestling with setting up some sort of network for the shack and office computers. This was wi-fi based but keeping the wi-fi dongles going despite Windows cheerful but destructive updates finally beat me. I also found it hard to keep the USB cables quiet. Several computers in a room should be wired for internet connectivity, or so my out of date thinking goes. The problem was that my last (also second hand) computer produced dreadful noise when connected to an ethernet connection. That computer has been stripped down to the mother board, fitted with a new processor, got up with new peripherals and power supply, and mounted in a new box. So everything was approved noise free except the one thing that changed, the motherboard.

Having left it on wi-fi for months while I cogitated on this issue, I decided that the ethernet socket must be at fault. After all, that was the story behind the BT modem. I bought a USB3.0 to ethernet link to allow the internet access to reach the computer via  a different route and first trials suggested that this made no difference.

After allowing all this to mature a bit further, I decided to move the internet access point closer to the computer and use a better quality ethernet cable. I chose a CAT 6 cable, well screened with metallised plugs and only 500mm long. This replaced a CAT 5 with plastic plugs which was 1.5m long. The result was remarkable. Not complete silence, but manageable.
Not all ethernet cables are the same: Left screened CAT6 with metal plug, right regular CAT5 with plastic plug.
I am beginning to wonder if all ethernet plugs and sockets are suspect. Next project is to screen the USB3 to ethernet converter using the "Bacofoil" method to see how that works.

It is worth it. I now have both radio computers linked via a wired connection which is not only quicker, it allows ShareMouse to work perfectly and allow me to use just one keyboard and mouse.

New sources of interference pop up all the time. Just moving a cable can cause problems. At the extreme I have turned off the house mains and run the radio on battery power to see if it was coming from within this house (in that case it was). A simple test is to listen to the radio while you turn off the suspect device and unplug the power supply. Most computers create some hash but some if it can be tolerable.

We have a general rule in this house the every device should be turned off at the mains if not in use. This extends to two "smart" TV devices. The policy also saves on the electricity bill. Simple ferrite filters work remarkably well. I have recently invested in a commercial mains filter as I have no other protection against common mode interference entering the rig power supplies via the mains. I doubt if this is a major issue but it seems worth being able to test it. And so the battle continues.
Cross Country Wireless mains filter - still being evaluated
I guess that I may yet be affected by the sort of over-powering interference which has put other amateurs off the air. However, it will not happen until I have tried my best to carry on using my own best efforts and a few simple precautions.




Friday, 24 November 2017

Leonids, another brief Es opening and a new type of radio amateur.

This time of year is really the peak of the meteor scatter season, though I am always quick to point out that meteor scatter is possible all year round. Certainly a trio of major showers and a few minor ones can make the period between mid-October and mid- January very productive.

The Leonids shower peaked around 17 November, but I found 16 November most active. Then of course as 18 and 19 fell on Saturday and Sunday, those days looked pretty good. Weekends always make the propagation look better.

I was fairly busy with other things but I managed this:-
4m and 6m Meteor Scatter contacts at GM4FVM 10 to 24 November
As I mentioned, the peak time here was the evening on 16 November, with long sustained bursts of signal.

Well, that map is not quite what it seems. The contact into Croatia (9A2DI) sounded more like Es than meteor scatter. At that time, 17:20 on 21 November, my 10m WSPR station was receiving hits from the South East.
10m WSPR spots at GM4FVM, 21 November
I quickly had a look at Solar Ham to see if there had been a sudden rise in the X-Ray graph and as usual in these situations the blue graph had shown a sudden rise on 21 November.
GOES X-ray flux graph 19 to 21 November
Also at the same time, my aurora alarm had gone off as one GM station was hearing Norwegian beacons on 2m via aurora. He is a lot further North than me. I heard very little in the way of aurora, at least as far as I could confirm. There was a lot of noise on 70MHz and some peaks which might have been beacons, but I would not call that a confirmed aurora.

I was already on aurora alert following the appearance of a large coronal hole, number 42, which was noted a couple of days earlier as being likely to enhance auroral conditions on 21 November.

Despite hearing 9A2DI for over 45 minutes, with a strong Es signal, nobody else seemed to be workable from here. Various stations were posting "Es" as the means of making MSK144 contacts but MSK is not very useful on Es - 9A2DI was filling my waterfall. Switching to FT8 I got no response and saw no stations. Es events like this are often very localised, but I cannot help thinking that at 17:20, in November, near the bottom of the sunspot cycle, there just were not many stations around on 6m from the Balkans region.

Anyway, 9A2DI worked quite a few stations in "these islands", so at least there were a few operators around from near me.

This looks like a classic "disturbed geo-magnetic conditions short of an aurora" type brief opening. No surprise to me as I have been banging on about these openings for years. Or "pre-auroral enhancement" if you prefer that expression.

I suspect that those X-ray figures are not quite the full picture. I might have expected most of the X-rays to arrive at the same time as the coronal hole was visible facing the Earth, which the SolarHam photo shows was 18 November. In fact the enhancement occurred when the solar wind speed rose, which was 21 November. However, I suppose that X-rays can result from the activity in the material contained in the enhanced solar wind. Or the X-rays are just a consequence of the arrival of the material effects of the coronal hole.

Even though the X-ray figure works as a sign of the opening, I would expect measures of increased arriving protons and electrons would give a better sign. This is something which needs more investigation (by me at least).

My own take on what is happening is that the ionosphere is energised by the arriving particles (and the associated X-rays show up on the graphs) and that is enough to push a small area of the E layer into providing Es propagation. This event is obviously a lot less energetic than the full sunlight would be, so the area of ionisation is smaller and fairly short lived, making the propagation very localised. Mind you, 45 minutes is surprisingly long for a winter Es event. Also that was propagation at 50MHz.

Many of these short lived Winter Es openings (no doubt they occur in Summer but we don't notice them amongst generalised Es) only show up here up to the 10m band. It was nice to see one at 50MHz for a change.

Frustrating, watching Es on MSK144 where only one station can be received at a time, especially after you have worked the one station and he then fills your receiver. Still, I could watch it on 10m WSPR.

So perhaps my map of contacts during the Leonids needs to be qualified by saying that working 9A2DI was really Es.

I like exploiting these short openings. You need to put in the hours but they are there to be found. It is another part of amateur radio which proves the old adage "Amateur radio is for life, not just for Christmas". You can treat yourself to a shiny new rig, but to get the best out of radio you have to do the work.

I was interested to read recently, on the ARRL site, mention of a new breed of amateur who uses amateur radio to pursue their interests in computing and propagation. This might be fine but it seemed to worry them that there new amateurs are not interested in circuit diagrams or drilling boxes to fit switches.

I am beginning to realise that I am not a "proper" amateur at all. Even though I was licensed over 40 years ago, I can now see that I am one of these "new" amateurs.

Eh? The first of the new wave? Not my style.

Switching from reading soldery old Practical Wireless to irreverent Radio User seems to be sign that I have decided to "come out" as a new amateur. Not that many of the readers of Practical Wireless ever bothered to make any of the circuits mentioned there, but there seems to be some need to keep up the pretence that lots of us build our own rigs. We don't. Or at least I don't, I never have, and I never will.

Radio User is probably only 50% relevant to what I do. On the other hand, Practical Wireless was about 30% relevant to what I do, and getting less so all the time. Of course, I still take the RSGB's impressive organ, "RadComm", which I will not risk assessing in percentage terms. Lets just say that "news" to me should be about radio, not about administration. The fact that some old duffer has been a member for 70 years is not really as newsworthy to me as short durations Es openings, which they never mention anyway.

Radio User now has Tomas Hood, NW7US as their new columnist for propagation. His first article has the modest title "Space Weather, the Sun-Earth Connection and Radio Propagation", which is fairly wide subject area. I suspect this is to get us up to speed for what comes next. It is really a pretty good article. I hope that he continues in a similar vein.




Thursday, 2 November 2017

Great October, data modes, noisy modems and getting angry,

I feel the need to sound off about the ridiculous nonsense talked about data modes by people who don't know anything about them. Indeed, I feel abused as I am one who often says that amateur radio is open to all, yet it is me who is getting insulted by others who seem to suggest that using data modes is "cheating".

I have been reading this sort of nonsense in Practical Wireless magazine where there is talk of the need for "proper" QSOs and fears expressed about new data modes undermining the results obtained during great Dx periods of yesteryear. Yes, like we should accept less Dx to preserve the history of the achievements of the Editor of Practical Wireless magazine.

Having cancelled my subscription to PW in protest, I find local amateurs droning on in similar vein. At a recent tea with some locals I had to explain that data modes like FT8 are radio and not internet linking modes. "How do you do it then?" they asked. "First you get a radio and an antenna", I replied. "Oh, I didn't know you used a radio for that". I think they are confusing digital voice modes such as D-Star with non-internet communication - even though you need a radio for that too. I had to explain how I made these QSOs in a one word answer - "radio".

I also got told that these local amateurs did not use computers or digital anything, which is interesting as they both use digital signal processing in their rigs.

The depressing thing was that I knew the outcome of this conversation before I met them. Almost word for word their reaction was infuriatingly predictable. They know nothing about data modes, they do not want to hear about them, and they regard them as cheating. Actually, they regard beam antennas and linear amplifiers as cheating too. They are entitled to their view, but surely so am I.

For now I am leaving this to fester in my mind until later.

In the meantime, Bri, G0MJI, has summed up the topic well here.

This is a subject I need to come back to. I keep saying that there is enough room in this hobby for all interests, but others seem to consider that my interests are a threat to their idea of amateur radio.

I am old enough to remember people saying at different times that SSB, FM, repeaters, satellites and commercial rigs were going to be the death of amateur radio too.

It has been a great month. My 6m tally for the first four weeks was this ..
6m contacts at GM4FVM in the first 4 weeks of October 2017
I find this result surprising as only one QSO was on meteor scatter and all the rest were on Es. As I explained before there were several increases in X-ray energy reaching the Earth. Then towards the end of the month there was an event I call "geomagnetic activity short of an aurora". Apparently it is called "pre-auroral enhancement" by those in the know. I am not sure that is a good expression for an event where there was no aurora. Anyway, lots of nice Es at a time when the prediction sites said nothing was expected. Then they cover their mistakes by ignoring the resulting openings.

For 10m it was even better, with E and F-layer openings bringing me new DXCCs in the shape of India, Bosnia and Gibraltar amongst others. Turkmenistan was an interesting one, as most sources say that amateur radio has been banned in that jurisdiction. Maybe that is one I cannot claim.
12m contacts at GM4FVM in October 2017
Both these results run contrary to the commonly-held view. The commonly held view is that 6m Es is a summer only thing, and also with the solar flux level down about 75 there is no point even trying 10m.

As I suggested last time, the commonly held view is often wrong. I keep reading articles about nothing being workable with the SFI in the 70s.

There are two things which seem to arise here:-

1) Although almost all of those contacts were made on FT8, looking back over previous years suggests that similar results were also possible on JT65 and even more so on JT9. I looked at a PY station with interest to find that I had worked them before in February 2016, on JT65. FT8 is not better than JT65 or JT9 in efficiency terms, what it offers is a quicker QSO. Lazy operators like quicker QSOs, so it is hugely popular. If it is popular there is more chance of me making contacts using it. More on this issue in a later post.

2) I am not going to suggest that November will be as good. It might be, but the only way to find out is to look and see. There is no substitute in amateur radio for being on the bands, calling CQ. If you are looking for a prediction from me forget it. As a modestly powered station with simple antennas I get my best results when the big guns are sitting with their feet up. So when the bands opened in October I make hay, knowing that most "weighty" operators are following the lemming idea that at this stage there is nothing to work. I might sit and hear nothing in November, but I will not mind. Why not come on the bands and join me?

This does not just happen by itself. I have finally installed the M&P Hyperflex co-ax on my 6m beam, and for the moment I have put back my 5 element PowABeam in place of the 3 ele Sirio.

I have also replaced the half wave vertical dipole (Sirio Gainmaster HW) with the 5/8th wave version (Sirio Gainmaster Classic), thereby reversing my decision to change them last year. This immediately improved 10m  performance and gave me back 12m. I am very fond on the 12m band. I have even dug out my LDG IT-100 ATU to use with the IC-7100.
IC7100 (left) and LDG IT-100 (right)
The IT-100 works well with the IC-7100. It is controlled direct from the rig TUNER/CALL button on the IC7100's control head. Although rated for 125W of SSB, the IT-100 is only capable of 35W of data modes. I am fairly certain this limit applies to modes such as digital voice, whereas in operation I find that 15 second bursts of FT8 pose it no problems at all. We shall see!
My relentless pursuit of a low noise environment goes on. Some time ago I pointed the finger at BT Openreach's fibre modem.
When "fibre to cabinet" broadband came to this village I changed over broadband service provider, leaving BT. At that time the network operator, BT Openreach, did not permit anyone to connect a third party router direct to the copper wires which link to the cabinet. I should perhaps explain that in the UK fibre to the premises is only available in certain limited areas, mostly big cities. Elsewhere you have to use your existing twisted pair telephone cable to reach the fibre enabled street cabinet. And that means that your broadband provider is, of necessity, BT Openreach, and you have to follow their procedures.

Fibre to cabinet is in fact fairly effective, increasing my broadband speed by a factor of 5. However, my broadband provider had to get BT Openreach to provide the modem pictured above, and then I had to connect their router to it.

None of this would matter much had the BT Openreach modem been quiet, but it certainly was not. I got strong birdies all across the VHF spectrum. For a long time I chased around adding screened cables and changing power supplies before realising that the noise was coming out of the box itself, and particularly out of the ethernet sockets. Eventually I calmed it down by adding aluminium foil ("Bacofoil") screening over the sockets. That was better but still not perfect.

There are millions of these modems in UK homes. That is hardly surprising because BT Openreach insisted on them, and the only way of avoiding them was to buy your internet from Openreach's parent company, BT. BT could provide you with an integrated modem/router, but no other broadband provider could. And as BT Openreach owned the network, that was that.

I thought about screening the entire modem. The snag with this is that the Openreach modem has a fearful reputation for overheating. It even came with a sticker warning me not to obstruct the vents. MM0XXL donated a large screened box with built in power supply and a fan so that I could both screen it and ventilate it at the same time.

Then eventually I discovered, by chance, that BT Openreach were no longer offering to maintain the modems. Further digging revealed that a year before this Openreach had dropped their requirement that this device had to come between any non-BT Router and their wires. So I was now free to buy an integrated router which would plug directly into the twisted pair.

I had already spent quite a lot of money on a nice fast and secure router which would cost a fortune to replace. So I decided to buy a simple TP-Link combined router, configure it to run as a modem, and then feed my router with a screened ethernet cable. This, combined with screened phone cable from the main BT Openreach box where the line enters the house, produced instant radio silence at a cost of under £30. My broadband speed has gone up 30% too!
Unusual styling of the TP Link router now acting as a modem.
It looks a bit odd. It has many many vents and slits all over it, but it does not radiate any RF that affects me. Problem solved.

Openreach had dropped their requirement to use their modem long before I heard about it. I must have had one of the last ones fitted. But it is solved now.
There are new versions of WSJT-X and MSHV to report on.

WSJT-X v1.8.0 is now an official stable release, replacing the trial rc2 version. Various improvements have been made. It is now possible to save your frequency list, something which I will find handy as I had to laboriously delete lots of entries from it every time I updated in the past. This became available in rc2, and now the full list appears or you can re-install it by clicking "reset". Very handy.

A bit odder is the way clicking on the waterfall affects your operating frequency. In the past you could select "Lock Tx=Rx", which was pretty self explanatory. Now that box has disappeared and the options look like this:-
"Hold Tx Freq" allows you to keep your Tx frequency fixed while clicking on text to answer a call on another frequency inside the waterfall. This is to allow the use of split frequencies.

The use of splits within the filter (i.e. within the waterfall, not on a different VFO setting) has mushroomed since FT8 became popular. DX stations, i.e. those lucky enough to handle pile-ups (is that lucky?), call CQ and take calls from all over the waterfall. So you can call a DX station from any point in your SSB filter, and the DX station will generally reply on the frequency they called on. The reason this is done is that if the DX station listened on their own frequency they would not get a decode due to the high level of QRM there. This way they can hear stations calling them in the clear.

So that is great for Dx operators, but for the rest of us the outcome is a bit more tricky. Clicking on the waterfall now moves only the rx frequency. To move the tx to the same frequency press shift on your keyboard and click on the mouse button again. Or click the Tx<Rx box. If you press AltGr on the keyboard and click on the mouse button then both tx and Rx move together (as if the old Tx=Rx Lock button was selected). This is how I find it works with a UK standard QWERTY setup, anyway.

So if you hold AltGr key down on the keyboard, then clicking on the waterfall moves both frequencies just like it used to do with the Tx=Rx lock operating.

No doubt all this will become second nature after a while.

It would seem more sensible to me if things worked the way most of us operate - on a single frequency - with the options for the others. After all, if everbody used a split frequency we would all occupy twice the bandwidth.

MSHV went through an odd stage of development when, in MSHV 1.51, the FT8 mode was removed as that mode was still in development. This was no doubt because WSJT-X 1.8.0 was in testing. Now that WSJT-X 1.8.0 is on stable release I had hoped that MSHV would restore FT8. This has indeed happened. MSHV 1.53 includes FT8 as well as retaining PI4. Whether MSHV is better or worse at decoding PI4 than PI-Rx is something I am unsure about, but receiving PI4 certainly works on MSHV.

MSHV still runs with a lighter processor load here than WSJT-X, and that still matters to me until such time as I upgrade my PCs. MSHV also has a full range of watchdog timeout options, able to be defined in either time or number of Tx periods.
Well, back watching to the exciting end of Masterchef Australia 2017. Very exciting.

Perhaps I should collect some mushrooms first.

I think that Sophie Ellis-Bextor spoke to every antenna experimenter when she sang

"If this ain't DX ...
.. why does it sound so weak?"

Ah, Groovejet. My favourite airline.



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.