Wednesday 29 May 2024

May's bountiful gifts continue.

No, not Theresa, I mean the month of May.

I have been musing lately over the early arrival of various forms of multi-hop Es.

Three days ago I asked this question in an email:-

That is another day in May for transatlantic propagation, when in every other year apart from this one it started in early June. Will the same thing happen with the Japanese paths, which so far only occur for me in July?

And today guess what? A 6m opening to Japan.

The event kicked off with me working RO1M, 1956km away in KO59. Now that some more Russian stations are operating on 50MHz they do provide a pointer to when the band is open further East. They produce a lot of new squares too. Then I started hearing JA.

DX Maps on 50MHz at 08:27 on 29 May 2024.

This map looks pretty good but as usual these openings are often scrappy. I worked two stations JR1LZK and JA7QVI. Best DX 9164km. I also had another possible QSO which was a bit doubtful and I await confirmation. I am not complaining about working two, but I did hear a lot more.

JA on 6m in May is certainly an unusual event at GM4FVM. In fact, JA at 6m at any time is an unusual event GM4FVM.

Perhaps even more surprising was that several stations in GM were hearing a VK station later. Indeed a number of stations in these islands worked into VK. I did not even hear that station. Not that I am bitter about it of course.


There was a general Es opening and I was particularly busy on 70MHz:-

70MHz contacts at GM4FVM on 29 May 2024

Click image to enlarge if needed.

12 contacts on 4m in a morning is not at all shabby. Of course the best DX was to UN7MBH in LO51. That was my best DX on 70MHz so far this year at 3480km and my first contact into Asia on 4m in 2024.

The opening extended to 144MHz, though I did not manage to work any DX. I heard stations from Sweden and Kaliningrad, but neither of these produced a contact. I was heard in the Baltic and as far away as 2450km into Russia, but sadly nothing resulted. 

As I write this, the opening is still going on at 14:46. Although it has lost that initial power, it is producing good DX on 4m and 6m. Usually the double peak nature of Es means that morning openings rarely last into the afternoon, and afternoon ones rarely start in the morning. If both periods are involved the two openings are usually in different directions.

So there are you. Quite a morning. JAs on 6m in May, VK heard by almost everybody (not me), good opening on 4m and I was widely heard on 2m.

Whatever next.

73 Jim


Tuesday 28 May 2024

Es underway and Transatlantic propagation sweeps South.

For this posting I am going back to consider my QSOs over the past week. The week before I was sailing down the Rhine, and the photo shows myself and Mrs FVM enjoying Strasbourg in a typical pose of our various outings.

FVM and Mrs FVM enjoying the Strasbourg streetscene.
We are back now and that week away has allowed the Es season to really get underway.

After a slow start, 70MHz has at last picked up.

70MHz contacts at GM4FVM from 21 to 28 May 2024.

Why do I spend my time on 4m when 6m was absolutely buzzing? Well, 4m is harder to do. The contacts require more work, you need to try to follow the propagation. A lot of the time you call and hear nobody. Who said amateur radio should be easy? Anyway, by the leisurely standards of 4m, 13 QSOs in 12 squares and seven countries is pretty racy. Best DX was SQ8AQX in KO00 at 1644km which is pretty good I think.

On 6m during the same period I worked 49 stations in 43 squares representing 21 countries. So more than three times the number of QSOs and three times the number of countries on 6m compared with 4m. Every QSO is interesting, otherwise neither the other station nor me would bother. However, for hair-shirt types like me there has to be more than churning them out.

If we look instead at 6m QSOs over 2250km we begin to see some more details. First of all, there are some. It is still only May and early in the season. In this category (6m over 2250km) I had five contacts.

50MHz contacts over 2250km at GM4FVM from 21 to 28 May 2024.

The reason why I chose the lower limit of 2250km is that the generally accepted limit for single hop Es is 2000km. I have had a few at 2100, so 2250 seemed like a safe bet. Beyond 2250km any Es is likely to be double hop propagation. So I was a bit surprised to see two contacts into Ukraine turning up on this map at 2264 and 2377km.

Anyway, the other three were KP4EIT (FK68 6752km), LU2GPB (GG03 10542km) and CE3CX (FF46, 11866km). The first of these was also likely to be double hop Es. The last two were ... who knows? TEP, F-layer, whatever. Certain stations near me were having open house working into LU and CE and good luck to them. The trick is to work them first and worry about the propagation later.

So here we are again still in May commenting on long distance 50MHz propagation. There is some juicy DX to worked in amongst the high volumes of Es around. What will the next month bring?

73 Jim


Monday 13 May 2024

10 May 2024 Aurora

 I was browsing about the news sites when I came across this on the RTÉ.ie pages:-

US authorities have issued the first Severe (G4) Geomagnetic Storm Watch alert in almost 20 years as a powerful solar storm will hit Earth, with one enthusiast saying there's a "good chance" of seeing the Northern Lights in Ireland.

It is unusual for general news sites to carry anything which might be of any interest to radio amateurs or sky watchers. So this had to be something important. Further information could be found at VE3EN's Solarham had it not changed from to, which threw me off the track for a while - thanks to Mike GM3PPE for putting me right there. Anyway there were several big CMEs on the way towards Earth, and in a configuration which suggested that faster ones behind would merge with slower ones in front and produce a stronger effect here. And so it proved.

GM4PMK magnetometer on 10 May 2024

As usual click the image to enlarge if necessary.

I worked 22 stations during the aurora over the 24 hours after the first arrival of the particle stream. 21 were on 50MHz and one on 70MHz. All of them were on Q65 as I could not even attempt to use the microphone due to having the cold and 'flu. This activity covered 10 DXCC and 20 squares, with my best DX being to OE5OLL in JN68 at 1352km. I probably could have done more if I had been feeling better. I also spent some time between midnight and 02:00 local time out in the garden looking at the visual aurora.

50MHz auroral contacts at GM4FVM on 10 and 11 May 2024

All of these contacts were truly auroral with no tone audible, even the fairly close contact with Mike GM3PPE which is only 31km direct but a lot further via aurora. During the time I also had some very useful contacts with Dave, G0ODA on 432MHz and Gordon GM4OAS/M on 2m FM, but no aurora involved there! Having said that, there were reports of auroral contacts on 432MHz, so this was a very powerful event. I did not have 144MHz available at the time and it never even occurred to me to look at 70cm. Possibly a lifetime only chance missed there, but CW was beyond me at that stage.

One unusual feature was a fairly widespread Auroral Es opening across the Atlantic on 50MHz. I listened for about 30 minutes while others worked across the pond but nothing from there was heard here. I have often experienced Auroral Es during smaller openings, but I have never known of a trans Atlantic event.

The one Au contact I had on 70MHz was with G4BRK in IO91 (bringing the total square count to 21). This was my first Au contact on 4m using Q65. I was calling using the Q65-15C variant but Neil and I both noted how wide the signal was. Although many of us started out using Q65-15C during this event, most ended using 30C as it uses less bandwidth. I can see downsides to both approaches so some thought needs to be given as to which one we should use in future. Usually, decisions like this are made in amateur radio by somebody picking something and everybody following, whether that is right or wrong (like using 30 second periods for 2m MSK144 in Europe).

Anyway, this aurora brought a lot of activity much further South than we usually get, and it must have created new DX records for a lot of amateurs. It may well be a new Au DX record for me too. I must look it up.

I shall leave you with some photos I took of the visual aurora as seen from GM4FVM.

73 Jim


Friday 10 May 2024

Transatlantic on 6m, the "new normal" on 50MHz?

[Why do you keep writing about Sporadic E Jim?] 

Because there isn't anything else at present.

Not quite true, there have been several auroras. These events all have something in common - I missed them. I got back in on 2 May just in time to catch the last of a good aurora and on 50MHz I managed to work G8BCG in IO70, a distance of 623Km. This is a pretty good result on aurora for me as G8BCG is probably the furthest south I have worked on aurora in the UK. Sadly, I missed everything else in that event.

But it is true that I am not writing about big tropo openings on the higher bands because there have not been any. Maybe soon there will be. Other esoteric modes = zero.

So time to consider again the issue of transatlantic 6m propagation. This is not due to storms positioned 2000km apart across the ocean, as I have been reading recently. I shall stay away from further discussion of what the mechanism might be, other than a final guess.

Since my first transatlantic contact from here with VO1SO back on 18 June 2011, there have been 31 days when I have had 50MHz contacts across the North Atlantic. For this exercise I am excluding Mexico, the Caribbean, Central and South America - this is North Atlantic only. This was done in an attempt to screen out Trans Equatorial Propagation which is tricky to identify.

After that first contact I had to wait a week short of five years until the next one. Then there were two days in 2016, five days in 2017, six days in 2018, two days in 2019, five days in 2020, three days in 2021, none in 2022, and six in 2023. Plus one now in 2024.

There is one feature which applies to all 27 days of contacts across the North Atlantic up until the end of August 2023. All of the contacts in that period were during June, July or August. The earliest was 4 June and the latest was on 24 August. This shows the characteristic lag mentioned in the last posting for Es contacts in general, starting about 17 days before midsummer and ending 65 days after midsummer, making the lag about 7 weeks (see last posting). Not much data for this one so maybe that lag is a bit exaggerated.

What makes the last four contact dates unusual is that they fall way outside the usual pattern. The dates are 27 and 30 November 2023, 1 December 2023 and 1 May 2024. If I needed more evidence that the Es season is getting longer then here it is (if it is Es). Before this week my earliest QSO across the North Atlantic was 4 June. The latest one was 1 May. 

I only made two contacts that day, and I failed to confirm a third one (VE1SKY). There were several stations heard such as K1SIX, K7BV, K1KA, WW1L etc. The point here is that this was a substantial opening even if I only worked two stations.

50MHz contacts at GM4FVM on 1 May 2024.

So what propagation gives transatlantic 6m propagation on 1 May? Is that the same process as in November and December the previous year? When my previous contacts on this path have all been during the period from June to August, it makes me wonder.

Sporadic E which is vastly more sporadic than I have ever seen, or F-layer, or something else???

All the books say that Es is not influenced by the sunspot cycle, and I cannot really see how it could be. Surely not that.

73 Jim


Tuesday 23 April 2024

Chasing Meteor Scatter on FT8, a fruitless business.

My last posting (finalised yesterday) was about the length and peak of the Sporadic E season. You can read it here, though it is just below this one on the blog.

This time I am mentioning a factor which makes 50MHz and 70MHz contacts at this time of the year difficult to classify. 

Difficult to work too.

There are often a lot of single decodes cropping up on my software just now. Some of them do carry on weakly to a second decode and the odd one makes it to a full QSO. Then there are sudden decodes which appear to come from nowhere, sometimes linking into distant propagation modes like TEP which seem like strange mini-openings. But after one strong decode they are gone. What is this thing which is teasing me?

The clue lies with meteor scatter. As I write we are in a meteor shower. When I look at dxMaps I see similar decodes on 144MHz, often over pretty well the same paths, on the 2m band. There are two differences - 1) the 2m ones don't often link into anything because those dx propagation modes are rare on 2m, and 2) on 2m they are listed as meteor scatter rather than Sporadic E.

Ah, I have at last found a reason why I watch 5 or 6 bands simultaneously. To find things like this, of course.

The maps of 6m and 2m propagation look very similar, but on 6m there are postings showing Sporadic E on FT8, whereas on 2m there are decodes as meteor scatter on MSK144. Look at the listings and you see that the 6m ones are just single decodes but the 2m ones are meteor scatter QSOs.

Meteor scatter propagation happens in the E layer when signals are scattered from ion tails left by meteors. At 2m these are fleeting short pings, but the same event produces longer periods of propagation on 6m. Thus it is possible to have good strength contacts on 6m using MSK144 and these show up as meteor scatter contacts.

Ionisation caused by meteors is short lived on higher frequencies but the effects last longer as we use lower frequencies. This longer ionisation period on 50MHz persists and can allow what looks like "standard" Sporadic E because FT8 can decode signals during bursts (at least briefly). This slightly longer period for 6m can permit a decode which is little affected by Doppler shift. So it is possible to have a 6m decode using FT8, and that tends to be posted as Sporadic E. If it happens to last long enough, a QSO can result using modes which normally do not respond well to meteor scatter.

Of course, it is ionisation on the E layer, it is short lived, so it is Sporadic E. But as it is directly caused by meteors it follows the general principals of the meteor scatter mode. Thus is tends to happen principally at the same time as meteor showers. Yesterday was the peak of the Lyrids shower, and these short decodes peaked then with me. It tends to peak at about 06:00 local time and decline during the day, as did this effect yesterday. You can get meteors at any time, but during the morning meteor shower peaks I see this type of propagation peak too.

Sometimes, during an intense shower you can get enough direct ionisation to form a small area in the E layer and get some prolonged propagation, but this is not so common. In a weaker form it can occur at any time too, but mostly I only notice it during shower peaks.

I first found out about this through a posting by another amateur who goes meteor scatter hunting on 28MHz during every meteor shower. On 10m the effect is more long lived than on 6m, and he can have quite a lot of success. I wish I could find that posting again. Anyway, once I knew what to look for it was easy to see. Here are the two maps for yesterday, 22 April at around 08:00:-

dxMaps of 144MHz on 22 April 2024

dxMaps of 50MHz on 22 April 2024  

At this time of year, and during meteor showers generally, you can turn on PSKReporter or DXMaps and see lots of 50MHz decodes reported, while there are almost no QSOs possible (try selecting "Only DX-cluster" from the DXMaps options during one of these events to see the difference).

So what difference does it make that this form of Es is created directly but briefly during a shower, when "standard" Es is just the same ionisation which has been organised into a layer (for details of that complex process see here)? The immediate effect is that it is very difficult to have a QSO on FT8 like this directly after a meteor burst. FT8 is not designed to handle it. MSK144 is a far better mode for this purpose. Also, the station at the other end may not be expecting to deal with single decodes in the way that most meteor scatter operators do. MSK operators will have long watchdog periods and keep transmitting for ages. Plus the key difference is that the MSK144 algorithm is far more sensitive to the weak signals as the level of ionisation tails off during the period of the ping.

It is Sporadic E, Jim, but not as we know it (with thanks to Gene Roddenberry, Bones, and the crew of the Starship Enterprise for that misquote).

To make full use of this effect, I suggest you switch to MSK144 and work meteor scatter on 6m - if you can find anyone else with the same idea. Or go down to 28MHz where the ionisation hangs around long enough to have an FT8 QSO (possibly). However, it only lasts for a day or two around a meteor shower peak.

Me, I just sit and watch as operators chase individual decodes. It must be frustrating. It was for me until I worked out why this happened at the meteor shower peaks.



Sunday 21 April 2024

Trying to estimate the length of the Sporadic E (Es) season and calculate the "lag".

I have recently been criticising some others for taking a few bits of evidence related to amateur radio and then building that up into a theory of Sporadic E. In my view this does not have credibility.

I am about to do something similar so this needs some qualification. I have been looking through my log book. This is obviously limited by loads of factors, but it still might be worth a look. There are 13859 entries in there, not the five data points which one of the other theorists used. Not that I have made 13859 contacts since I arrived at this location in 2009. Oh no, there are more than that. I am not legally required to log all my contacts, and a lot of local ones were not logged. That was in the olden days when there were local stations to work.

None of the missed log entries should matter for this purpose, as I have been very careful to log all my Es contacts. However, this is an early warning that we need to be aware of the many possible areas of bias in the data.

OK, I looked at the Es contacts at GM4FVM on 50MHz from 2011 to 2023. I arbitrarily excluded contacts from early December through to February to exclude "Winter Es" or "Christmas Es" or whatever you want to call that. This first measure was for the length of the season between the first contact and the last, not counting how many contacts resulted in any day or week. This method does not identify the peak of the season in terms of contacts, nor log periods with specific openings such as mini-seasonal paths to Japan or links to TEP. However, every Es contact in the log counted for this purpose including those specific ones. The data was aggregated up from activity days into activity weeks to make the maths practical.

I expected that the "lag" means that Es started later in the year and ended later in the year than a strict correspondence to the Midsummer Day (by which I mean 21 June -ish). I had expected to find that the seasons tend to be roughly the same length each year, just all shifted towards the end of the year.

Sporadic E contacts at GM4FVM 2011 to 2023 (1)

As usual, click if you wish to see an enlarged version of the images.

First of all, you can see the lag. It is about 4 weeks in the first period rising to about 5.5 weeks later. Es starts later than the Spring Equinox and now ends after the Autumn Equinox. So the data (as far as it goes) backs up my initial hunch.

Secondly, and unexpectedly, the Es season appears to be getting longer. The data seemed to fall into three distinct periods. That averages fell very close in each year within each four year period, and then there was a sharp step up to the later period each time. There were three distinct periods standing out from the statistics.

I really doubt that the period of enhanced propagation really is getting longer. I reckon it just looks like that. This finding took me back into my log for some explanation of what is happening. During the 2011 to 2014 period I was mostly using SSB ("pre data period"). During 2015 to 2018 I was using mostly PSK, JT65 and some JT9. Although FT8 was appearing not many people were using it (so this was the "PSK+JT period"). During 2019 to 2023 FT8 was in full swing and lots of people were using it ("FT8 period").

I may be wrong here, but I think that what appears to be a longer season is largely down to me switching from SSB via PSK and JT into FT8. During the SSB period I had to search out stations as they were spread throughout the band. During the PSK+JT period it was either the same spread (PSK) or I was using modes with long periods (JT65) or few followers (JT9). The sensitivity would have been higher than with SSB, but those modes did not have wide acceptance. Then during the FT8 period lots of stations appeared on the same frequency and the mode was even more sensitive. This is my theory about this; just my idea.

Working stations on Es on 50MHz has become easier over those years. More people are doing it, and that also contributes to what looks like a longer season. I doubt if the propagation has changed even though it looks like it has. It is easier to work people now because while at the start of my time on 6m stations had to have transverters, and build their own antennas, these days they have ready made equipment. Data modes have become much easier to use, computers have become cheaper and faster. Also we no longer need lossy data interfaces but we can now pass digital audio in our radios via USB plugs. As it gets easier, more stations come on looking for DX, and the season appears to extend as marginal propagation gets exploited.

Now that I had the basic information that it is indeed shifted to later in the year, I started thinking about the "shape" of the season. It feels to me that once the main season starts, usually about 4 weeks after the first contact, it suddenly bursts forth and reaches a quick peak, and then subsides gradually until the end.

So how to find where the peak is? My data measured so far is just contacts spread over time. It does not show when the main burst of activity happens. I could only do this on 50MHz by going over every contact individually - which I might do some day but not right now. There are thousands of them. So what might measure the timing of the peak? It dawned on me that my 2m Es contacts usually only happen at the peak.

I make the usual pre-condition that these are just my own data, and sometimes I am away, not watching 2m, or something similar. I spent a lot of my early years here thinking that 2m Es was rarely possible from this far north. Would there be enough data? Well, just like on 6m, the spread of data modes has provided me with a lot more data than I thought I had - 31 data points. There are bound to be fewer as these probably represent the peak of the Es propagation each year.

I then calculated those days from first to last contact and put them on the same graph:-

Sporadic E contacts at GM4FVM 2011 to 2023 (2)

The 2m contacts were almost symmetrically spaced on either side of midsummer. Unlike the 6m contacts where the lag was at least 4 weeks, the lag at 2m was almost zero (less than 12 hours) and not statistically significant.

This suggests to me that my second hunch that the Es peak comes in a rush towards the start of the season is also right at this station. However, just as on 6m, my figures just show when the 2m contacts happened not how big the opening might be on that day. Such figures on the "bigness" of an opening can be very misleading, as openings to my west are never big because there is just the Atlantic Ocean in that direction. 2m Es openings almost never include multi-hop Es, or not from here anyway, and nor have I noted them linking to TEP (not YET!!!). So the subjective quality of an opening is not something that I have tried to measure. But still, if the 2m contacts do indeed represent the peak of Es propagation then the peak here does not appear to lag behind the midsummer like the rest of the season does.

Now I want to go further into speculation. What might the shape of the Es season look like if I could work out the "bigness" of openings? Well, here is the FVM conjecture. I suggest that it looks like a gamma graph something like this one:-

Gamma distribution.

With apologies to whoever drew this, I cannot give an attribution as I cannot find where it came from via the internet. Let me know if it is yours; meanwhile I will try to find a better one. I am using it as x along the bottom axis looks like months of the Es season, and f(x) could be the "FVM-Es-bigness scale" [now you are getting carried away Jim].

Anyway, if this is roughly the shape of the season it would fit with the pre-data mode earlier years simply sampling the top part of the graph, say above f(x) = 0.3, and then as we got more sensitive modes and more activity we are sampling further down the vertical axis and finding the tail on the right. Thus the lag seems to be getting later and the season longer, which is what I found. 

Warning: This is just one guy's log history. It is not very reliable. I could do more and better statistical analysis but that would expose the unreliability of using any amateur's data. So it is not scientific, and no ham survey ever will be. Despite this I think it does provide something to think about.

When I was at college there was a lot of enthusiasm for using "qualitative" data. That is not gold standard statistically but it does show trends. What I have tried to do here is show what I have found in a qualitative way. It is up to you whether you believe it or not. For me, however, it has "face validity". It seems to explain what I have been seeing over the years.

First thing I can see is that the lag on 6m pretty well rules out Es linking into TEP in the Spring from here, but would suggest that is more likely in the Autumn. A quick check suggests in my case that Es linking is at least 9 times more likely to happen in Autumn. Secondly, I had better not rely on the lag to look for 2m Es contacts later in the year, as they seem to be equally spaced around midsummer. I will miss them if I wait. And thirdly, whatever the reason, it is worth hanging on looking for 6m Es right into the tail of the season, certainly in October and even later.

This works for me, and I hope it sheds some light on the Es season in some way for others.

73 Jim


Friday 19 April 2024

Bernd Wilde, DL7APV, SK.

I learned via the EI7GL blog site (see link in sidebar) that Bernd, DL7APV, has become silent key.

Bernd was a fixture on 432MHz before he constructed his massive antenna in 2018, and after that he introduced many to the potential of the band. His behemoth array has 128 11 element antennas formed into a vast box with an overall gain of 33.7 dBd. Not only did I work him via Earth-Moon-Earth using this monster, I also worked him easily on tropo at a distance of over 1000km.

Bernd, DL7APV, now sadly SK, and his 70cm antenna

I will miss Bernd's gentle reminders about upcoming contests. He had a delightful way of expressing his wish for me to come on and give him a contact via moonbounce. He would send me an email and point out the date of the forthcoming event. He would then say that if it could be fun for me to have a contact with him, it would also be fun for him to have a contact with me during the contest. He did not say "come on and work me", but rather he correctly pointed out that I could if I would enjoy it. He was right: I did enjoy it.

Actually there was no need for a formal sked, I could hear him very clearly and reply to his CQ call. My antenna only has about 14 dBd gain, so he was doing all the work. No doubt he sent similar E mails to large group of operators who, like me, had enjoyed early EME success working Bernd on 70cm. 

I shall miss Bernd and I send his surviving family and friends my condolences.

Where will we ever find such an enthusiast again?

73 Jim