I am a great one for watching the Internet for opportunities to work DX.
Many sources of intelligence are used at GM4FVM, Solarham, PSK Reporter and often also the excellent DX Maps.
DX Maps is very useful on three counts. It has contact maps so that I know where to point my antennas. Then secondly the MUF Sp-E map is derived from that information and it shows the predicted maximum usable frequency for locator squares over Europe. This means that I can see Es developing and, perhaps more importantly, fading. And finally it shows lists of QSOs reported and also allows me to post formatted reports myself.
Here is a map showing all the activity as reported to DX Maps
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| DX Maps showing all reported 50MHz activity on 2 May 2022 |
Despite this there was no sign at GM4FVM that the 50MHz band was open.
When I went into the "Select Options" tab on DX Maps and chose "Only DX-Cluster" this was the map which resulted, which was much closer to what I was observing from here.
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| DX Maps showing "Only DX Cluster" on 2 May 2022 |
The difference between the two maps is, broadly, that the standard map shows anything reported (which includes automatic uploads), whereas the second one shows entries made by amateurs manually posting things to the Cluster. Not all of the manual postings to the cluster are for actual QSOs, some report simply stations heard, usually unusual ones. However, most of them are QSOs. On the other hand, the upper graph contains dozens and dozens of automatically generated reports many of which are simply single decodes.
The thing about this time of year on 50MHz is that there are a lot of stations calling CQ but not many having contacts. So these CQs get picked up and reported automatically by stations normally on receive. There is nothing wrong with this, but it tends to clog up the reporting system. Just decoding a single FT8 message (most are FT8, but not all) does not make a QSO. Not only is the E layer very unstable at this time of year, there is also the Eta Aquariids meteor shower which often generates these single decodes, plus of course random meteor pings.
Just selecting "Only DX-Cluster" often makes a dramatic difference. The effect can be seen on the "List" section of DX Maps which shows the postings in tabular form. Here is the latest one and as usual with images here you can click on it to enlarge the text.
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| DX Maps List on 4 May 2022. |
When I clicked "Only DX-Cluster" every one of these red automatic entries disappeared to be replaced by a list of manual postings in black type. Basically, everything recorded had been a single decode and in one case the same signal decoded on two frequencies at the same time. As far as I could see nobody was actually having a two way contact. Changing to manual postings suggested that, rather than several contacts every minute all over the Continent, there had not been a QSQ recorded for more than twenty minutes and the ones that were had been largely concentrated in a single area in Germany.
DX Maps is not the only site affected by this effect - PSK Reporter is too. In fact PSK Reporter is affected even more because you cannot switch it to "Only DX-Cluster". In that sense DX Maps adds a very useful ability to screen out almost all these one-off reports. Of course there will always be the odd one-off report, often due to random propagation enhancements, possibly caused by cosmic ray ionisation, orbiting objects, meteors, aircraft scatter etc. They can be quite fun to see on the higher VHF bands, but they never seem to last long enough to work someone. If only. I still reply to a few just "to be sure".
The very useful MUF Sp-E chart on DX-Maps seems to always include all the reports and you cannot screen out the "red" ones. It works very well when there is only really Sporadic E and not the random meteor scatter pings we are getting at the moment.
It is very handy to see the one off ones too, but it is easy to get carried away and think that there is an opening when there isn't.
For the record there have been a few short Es openings on 50MHz at GM4FVM but nothing on 70MHz yet.
As for 144MHz Sporadic E, well that will have to wait until ... (who knows?).
73
Jim
GM4FVM
Jim,
ReplyDeleteYou mentioned the ES-MUF chart, and it does indeed include all reports.
As usual, the truth is always in between, as you indicate. I find the MUF chart very useful, and yes, don't get carried away by a single report of high MUF, though it could be a genuine one.
I would say that, all in all, those sites are very useful to me, grain of salt included.
I would say that the automatic reports can be very useful to indicate the possibility, but I do have one other comment:
As I see it, some people report the wrong propagation mode from time to time. For example, a strong localized tropo opening can sometimes be reported as ES, and that becomes misleading, especially in the MUF chart. On lower frequencies (especially 10m) I notice that, given the excellent F2 propagation lately, some report F2 openings as ES. Less misleading as the propagation is usually there for longer time, so that one may be nit-picking by me ;)
Good to see you back in action, Jim,
Vy 73, Jan OZ9QV
Jan. Thank you.
DeleteI agree with what you say. Very often automatic postings can be useful, such as 2m Es where they are so quick that you have a chance to react.
Today at 06:00 PSK Reporter was showing a very good opening on 50MHz, so was DX Map until I turned off automatic postings when nothing was recorded at all. So as you say in between is about right and we can decide which to believe.
Yes, some of the propagation mode reports can be wrong. Also, if the posting in not formatted then sites like DX Maps will allocate a mode likely to be correct. Long distance tropo can be shown as Es and so on. Using DX Maps to generate cluster postings means that the posting is formatted with the mode included.
Now an old man like me sometimes makes mistakes, sometimes posts to the wrong band or wrong mode. This happens. What matters is trying to post accurately as often as possible. I hope others can accept the odd mistake. Even I am not correct every time.
Nit picking is allowed. We want to get this right if we can. The study of propagation is an art and a science. We must co-operate and do our best.
My theory: Es after an aurora is different from Auroral Es. Or: Is Europe to Asia propagation multi-hop Es or a different mode entirely? These questions maybe are the subject of a university thesis. I try to make the right posting but in cases like these we are into unknown scientific territory. We must try to do our best.
73 Jim GM4FVM