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Message-ID: <003801cb0ed1$5588bf10$4001a8c0@lark>
From: "Alan Melia" <alan.melia@btinternet.com>
To: "RSGB LF Gp" <rsgb_lf_group@blacksheep.org>
References: <AANLkTinPlqOiLpZLGeiyD44F17WyYrA3v33ZnWN8Sft3@mail.gmail.com>, <005501cb0e75$075f7510$4001a8c0@lark> <4C1B093F.3081.186EF1@dave.davesergeant.com>
Date: Fri, 18 Jun 2010 11:30:17 +0100
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Subject: LF: Re: Re: Changing solar conditions
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er No Dave, Mike WE0H was talking about DX effects in his posting, rather
than "trench telegraph" :-))   If fading is seen there must be skywave, even
from a ground loop............ ground-wave is of course unaffected. At a
range of 250 miles on 500k there will be a substantial skywave component,
even in daytime and high angle signals will penetrate further into the
ionospere before being returned so may be more sensitive to absorption than
say 136. Precipitated electrons can enhance daytime skywave but not at
geomagnetic activity levels we have seen recently.

Alan

----- Original Message ----- 
From: "Dave Sergeant" <dave@davesergeant.com>
To: <rsgb_lf_group@blacksheep.org>
Sent: Friday, June 18, 2010 6:50 AM
Subject: LF: Re: Changing solar conditions


> 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
>
>