Friday is propagation day again but, I'm afraid, there isn't much to report - or is there?
By far the most import information to impart is that the sun is blank again. Is this really news? I think so. According to Spaceweather, and I have no reason to doubt them, the sun has been blank (with today) for 25 days.
We should, if the signs were right, have passed through solar minimum and be beginning to climb out the other side but the number of blank periods seems to be increasing. It seems we are very deep into solar minimum so perhaps this minimum is going to be longer and stronger than before.
The solar flux has been 69 to 72 all week and there has been little geomagnetic activity so, all in all, a poor week again.
It was also a poor week for VHF propagation with no sporadic E and no real meteor activity. In the UK we have had high pressure taking over with the barometer rising to over 1000 and staying there. The weather has been overcast much of the time but the temperature has been warm.
The Solar Cycle - what is supposed to happen?
For those who haven't experienced a full solar cycle here is the information you need.
The sun goes through a cycle of sunspot activity which is caused by variations in its magnetic field. About every 11 years (but sometimes not exactly 11) the number of sunspots falls dramatically and then rises again.
During solar maximum, when there are many sunspots and the sun is very active, we have good propagation with DX filling all the HF bands even as far as 10 meters. If you haven't experienced it, it's hard to realise that 10 meters can be full of signals as you tune across but this is what solar maximum provides.
However, at solar minimum there is little sunspot activity and propagation conditions are poor.
To add to this, solar wind pressure is down and various other solar cycles have shown a lowering in intensity to make this solar minimum a very intense one.
So should we be worried?
I don't think so. Most of us (even me) have a short memory and can only go back a few cycles but if you go further back, say to the beginning of the 20th century then you will get more of a perspective.
The solar cycles at the beginning of the 20th century (cycles 14 and 15) also show deep solar minimums. So this minimum is not as alone as we think and maybe it's just part of a longer series of cycles.
You can read more about this interesting subject (and also see a graph of a lot more cycles) at the Wikipedia url below.
http://en.wikipedia.org/wiki/Solar_variation
Note, too, that around the beginning of the 19 century we had a significant dip - the Dalton Minimum - and at the start of the 20th century we had the two very low cycles referred to above so perhaps at the start of the 21st century we will experience another dip in solar activity.
Interestingly, the Dalton Minimum was also a time of lower than average temperatures for the Earth. This may also have been the case in the early 1900s. Open the url below and then click to expand the top illustration on the right showing global temperatures and see what you think.
http://en.wikipedia.org/wiki/Global_warming
By the way, to complete the information on the solar cycle you also need to check out this page on Wikipedia.
http://en.wikipedia.org/wiki/Solar_cycle
That's it for today, maybe by next week we will have some real propagation to report - or else the sun will have been blank for over 30 days!
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