[CQ-Contest] Sudden Increase Solar Cycle 25 Activity as we approach the CQWW CW DX Contest

donovanf at erols.com donovanf at erols.com
Thu Nov 26 02:19:59 EST 2020

Sunspot activity has increased dramatically over the last two months. 
Most days this month have had multiple and more active sunspots 
resulting in the solar flux index exceeding 100 for the first time since 
September 2017. SFI is likely to remain above 100 during the CQWW 
CW DX Contest and remain at 90 or above for at least another week. 

But recall that both the sunspot number and the 2800 MHz solar flux 
index are proxies for the the actual source of F layer ionization that cannot 
be observed on the surface of the Earth: extreme ultraviolet radiation 

We can't yet determine if this is a short term surge or a sustained 
increase in sunspot activity. We'll have a better understanding in about 
six months. 

The first year of increased sunspot activity is a sweet spot in the solar cycle because: 

- increased extreme ultraviolet radiation starts to open the 10 meter band, 
makes 15 meters more reliable including more frequent JA and long path openings 
keeps 20 meters open later into the night and opens it well before sunrise 
keeps the MUF into Europe above 7 MHz during most or all of the night 

- coronal hole high speed streams that cause elevated K indices during 
the declining years of the solar cycle and during solar minimum are 
now less frequent and not as strong, keeping the K index consistently 
low for about the next year. 

- fast coronal mass ejections (fast CMEs) that cause much more severe 
and more frequent geomagnetic disturbances won't start to occur 
regularly until at least late next year. 

- daytime D layer absorption that affects 160 and 80 meters much more 
severely than 40 meters hasn't yet begun to increase significantly as 
it will when we get closer to solar maximum 

- E layer ionization ( not sporadic-E -- that's completely different) hasn't 
yet begun to increase significantly. As we get closer to solar maximum 
consistently higher E-layer MUFs will blanket 40 meter DX openings 
until later in the afternoon. 

Enjoy the ride especially this weekend in the CQWW CW DX Contest 


----- Original Message -----

From: "Alfred Laun" <hs0zar at gmail.com> 
To: "PVRC" <pvrc at mailman.qth.net> 
Sent: Thursday, November 26, 2020 4:09:22 AM 
Subject: [PVRC] Solar Cycle Rise 

We are seeing the Solar Flux Index hit a daily peak of 104 already, even though solar minimum is said to have been reached only 11 months ago in December 2019. I thought this seems faster than it rose last time, so I went to 


to take a look at what happened just after the last minimum. According to that chart, monthly average solar flux bottomed out at 65.7 in July of 2008. Monthly average solar flux did not get to over 100 until March of 2011, or 32 months later. 

Granted, the last solar minimum began with an SFI about 2 points lower than this latest minimum, but still, it looks to me like the rise is faster this cycle. 

Yes, there are complications, like the difference between actual daily values and the smoothed daily values which are used to produce a visual curve that doesn't jump all over the place. And what we have today are daily values, not monthly values. But it still looks to me like things are moving along pretty fast. 

I am not a scientist, so I invite all of those interested to go to that site, hover your mouse over the curve, and see what you come up with. 

73, Fred, K3ZO 

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