Friday, 28 February 2020

Lots more Es in February, or just FT8 keeping us active?

50MHz Sporadic E activity over 12 hours on PSK Reporter 26 February 2020
The accepted wisdom is that Sporadic E is both unpredictable, and predictable.

The unpredictable aspect is that you cannot say if it will occur on any particular day, in any particular direction, or at any time of the day.

The predictable part is that it happens during the Summer and around Christmas. As to what "Summer" means, well that varies with band and latitude. Perhaps April to October in 10m, May to September on 6m, late May to late August on 4m and 3 days around the end of June on 2m. I know nothing about 222Mhz, and 432Mhz has the odd, very rare, event.

You just don't know which days, but you do know generally when to look.

We have discussed the Christmas Es season, or Winter Es as I call it, here before. December and January seem to be the best times, but we don't know when and really only 10m and 6m benefit with rare events on 4m.

Except, the predictable is becoming more unreliable in the sense that we are now finding more event "out of season". And even the unpredictable is becoming more predictable, with more events on more days during the season.

I am no expert but I think that data modes and FT8 are partly responsible for that.

There are many in the amateur world who will go into the technicalities of decibels and sensitivity for an answer to this. I am sceptical about that approach when it comes to unpredictable events. These same people think that using a 30 second meteor scatter program is better than using a 15 second one. In this certainty of theirs they are wrong, but let us leave that thorny topic for a later posting. Amateurs often choose to take the wrong path, and that is a matter for them. I find the 15 second logic easy to grasp, but then I am prefect in every way.

Returning to my thesis, I think that getting all the amateurs in the world onto one frequency, which is more or less what FT8 does, vastly improves the chance of them hearing each other. In fact, I am pretty sure that it will result in far more contacts and receptions being logged than most circuit improvement we could make to our equipment. And, dare I say, more significant than more sensitive data protocols.

The process started with RTTY and its working frequencies. Whereas SSB stations spread out and tend to miss each other, RTTY brought them nearer and allowed reception without tuning or actually paying attention all the time. This got a lot better with PSK, which showed all the stations together on one waterfall. It suddenly got a lot easier to find everyone. As an early RTTY stalwart, PSK so dramatically out performed RTTY that I never went back. I often say how dorky I find RTTY now, and how wasteful it is of resources. However, RTTY opened the door for lots of us.

From PSK I found FSK441 and JT65 great ways to work stations but once again they tended to spread out across the band. I realised what was going on when I understood the distinction between  slow modes and fast modes. WSPR is a desperately slow mode, with 2 minute transmit periods and glacially slow bit rates. But the results were stupendous. I could, and did, work so far on very low power that it would have been the equivalent of 2,000,000 km per watt. But we always knew that the station at the other end would be on the same frequency. Not only did the efficiency of the data mode play its part, but so did having hundreds of others listening for each other, all on the same frequency.

The next step from JT65 was JT9, a simply splendid narrower mode where everybody could share the waterfall. And so eventually to FT8, where the whole world can listen together and you can reasonably expect to find everybody else using the mode. Unlike the fast modes (like MSK144 and fast versions of JT9), you are presented with a waterfall of stations, and they can operate on some sort of shared basis on a single SSB-filter wide part of the spectrum.

FT8 is a slow mode. It is not terrifically efficient. You could make it more efficient by slowing its data rate down some more which would make it more sensitive, but then you are heading towards WSPR territory. FT8 is a compromise which allows us QSOs rather than just beacon operation like WSPR, at the cost of some sensitivity. But never mind the sensitivity, you can work more people because they are all there waiting for you.

Is amateur radio there for chatting about pig farming techniques (yes, I listened to that QSO), or is it here for us to find out something new? Putting everybody on a moderately efficient mode which records reception and does not need to be attended to every moment, all on the same frequency, is likely to maximise the chances of reception. Whatever the sensitivity, it raises the probability of reception taking place, and thus QSOs.

So it is that I think I am finding more Sporadic E in February. Lots more. I cannot remember the figures, but I think that FT8 is less sensitive than JT9. But that does not matter much, as far more stations use FT8, so there seems to be more Es. Ultimate sensitivity does not matter so much for Es, where the signals can be quite strong. WSPR might be more sensitive, but the signals are not steady enough to last 2 minutes. Fast modes might be even better at handling the QSB, but 15 seconds is a good test - it is rather like having an SSB QSO. Fast modes would benefit from scatter enhancement, but with FT8 we can be pretty sure we are witnessing Sporadic E (erm, does this help explain why there are so many modes???)
50MHz sporadic E activity on PSK Reporter over 15 minutes during 28 February 2020 - pleased to reach OY.
OK, I know February has 29 days this year. However, I was away in Grantown on Spey for five of those days, and anyway it did not occur to me that this was happening for the first half of February. My effective study period covered a maximum of 23 days out of a possible 28 (I am not waiting for day 29). During that time I worked DX stations on Sporadic E on 50MHz on 8 days out of a possible 23.

8 days Sporadic E out of 23 in February? That sounds more like April. I would have expected February to produce one or two Es days. I had to check - had this ever happened here in February before?

Now, there are a few issues to resolve before checking the logs. Firstly some days I only worked one station (that happens in April and September too). I have excluded any stations within tropo range though they appear on the maps.

Quite often I worked SM5EPO (in fact on five different days), but it was Per-O who was around. Often the path opened to Sweden, but recently also to the Faeroe Islands where OY1OF heard me repeatedly on several days, but no QSO resulted. I worked mostly into the normal Es distance destinations - France, Germany, Italy, Norway, etc.

I have left out of my figures any one way reports, though there have been lots of them too. I have also left out partial QSOs. These get to exchange of reports but not RRR, so they get a ? in my log and are not counted. Where the callsigns are exchanged but not the reports I do not log them at all.  So I am sure that QSOs on 8 days is a fair statement - there are no partials in that figure. There has been more activity, sometimes just a couple of received messages or a partial QSO, on about 8 more days, but I have ignored them for the figures.

As for the total number of QSOs, well the Es opening on 11 February skews the results. It is not the number of contacts which is the key measure for me, but the number of days it occurs. Still, if you want to see activity on 6m from 1 to 28 February here it is :-
FT8 50MHz contacts at GM4FVM 1 to 28 February 2020
Ploughing through the logs was a tedious business.

The comparable figure for February 2019 is zero. NIL Sporadic E contacts in February 2019. I have not been able to drag up my FT8 listening  log but I bet I was listening on many days in 2019.

Figures for other years:-
2010, 2011, 2012, 2013, All NIL
2014 - 1 QSO (SM5EPO of course)
2015, 2016, 2017, 2018 All NIL.

I was alive and working during all those February dates, and I did work people on meteor scatter or tropo. Apart from that one day in 2014, I never noticed any Es activity. I would, of course, as anybody else on tropo or meteor scatter would, hear any of those stations via Es and reply using whatever mode we were on. There were none in February except one QSO on one day.

So, if it is true (and it might not be true), why is there suddenly Sporadic E propagation now? I doubt it. I think there are more stations listening on FT8 and ready to work someone. In other words, I just noticed it, and so did enough other people to work me.

Sure, there may be more unpredictable Es this month of this year. There was the opening on 11 February 2020, which was associated with increased geomagnetic activity. Likewise, during the short openings on 27 and 28 February 2020 I noticed that the K number as measured at the GM4PMK observatory (see link in sidebar). I certainly believe that on days when Es is not likely to happen, a spike in geomagnetic activity can push it into action. But all these issues arise every year, perhaps even more often at better stages in the sunspot cycle.

I will not bother to comment on the effect of Jet Streams as it appears to be NIL.

Is this Es and not some other means of propagation? It is certainly patchy, there is a lot of one-way propagation and quick QSB. I can see "pings" of signal which looks a bit like meteor scatter but that cannot explain it as there are no major showers now, and when it does get stronger it lacks the characteristic meteor patterns.

Is FT8 just better than you think it is Jim? Maybe, but I was using it last year too.

For sure, you do get occasional reception over great distances on FT8. Those are random events and almost always just for one reception (I suspect they are caused by either cosmic ray ionisation or random large meteors). This year's events were all long enough to secure a QSO. Looks like Es to me - and everybody else who reports it as such.

So there you are. I might be wrong.  I often am wrong, which you may have noticed.

I think this may simply be a measure of FT8 activity on 6m as much as increased Es.

I cannot lose here. If Es really is getting more common so much the better. Bring it on. If it is not getting more common, thanks to Joe Taylor and FT8.

Actually, thanks to Joe Taylor for FT8 anyway. Nice one Joe.




1 comment:

  1. This comment has been removed by a blog administrator.