From: "Dave Sergeant" <dave@davesergeant.com>
To: rsgb_lf_group@blacksheep.org
Date: Fri, 18 Jun 2010 06:50:55 +0100
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Subject: LF: Re: Changing solar conditions
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On 18 Jun 2010 at 0:04, Alan Melia wrote:

> You have found that Kp and A are not good indicators of propagation
> conditions at LF. 

And it is worth also remembering that although the K instance is 
'instantaneous' and updated every 3 hours, the A index the average of 
all the individual K indices over the past 24 hours. To that extent the 
A index indicates what YESTERDAY's conditions were, the K index is the 
only one that really shows what is happening NOW. A K index of 2 is a 
fairly low level, the 5 it got up to earlier in the day is edging on a 
significant storm. But in any case with a SN of 0 and a flux of 70/72 
the sun is effectively dormant. I don't think the geomagnetic 
disturbance mentioned was even worth mentioning.

I see this morning the flux remains at 70 but they have identified a 
few speckles invisible to the human eye as 'spots' so the SN is now 14 
(ie 4 speckles in one group, not 14...). K remains at 2. Nothing 
significant happening there.

Remember also we are largely talking about tests by groundwave, 
certainly so for Roger's ground electrode tests, and not transatlantic. 
In these what is going on in the ionosphere is totally irrelevant, 
groundwave does not go anywhere near the ionosphere...

73 Dave G3YMC

http://www.davesergeant.com