[TowerTalk] Sunspot Free

[jimlux]

On 9/11/19 6:05 AM, Don Havlicek wrote:
> There have been minor sunspot regions in the past year, but nothing sustaining.
> 73
> Don
> N8DE
> 
> Sent from my Verizon Motorola Smartphone
> On Sep 10, 2019 9:45 PM, john at kk9a.com wrote:
>>
>> Wow, what is the record?  I guess I haven't missed much being QRT
>> since the March WPX contest:)
>>
>> John KK9A - PJ4R
>>
>>


The record? Probably the Maunder Minimum from 1645 to 1715

And as always, there's some discussion in the scientific community about 
what constitutes a sunspot, what the correlation between sunspot number 
(or Smoothed Sunspot number) and solar activity is, etc.

The propagation models all take SSN as an input, but what really affects 
the ionosphere is the intensity of the UV light falling on it - 
unfortunatately, there were no orbiting satellites to measure UV 
insolation nor any ionosondes back then, so counting visible sunspots 
serve as a proxy for solar activity.