[Lf] Sun spots and Terman]

[Andre' Kesteloot]

Alan Melia wrote:

> Hi all, this is a interesting problem...is LF going to get better, or worse,
> as we go down into the next solar minimum ??
> The problem with Terman's graphs are that they are 'averages' and looked at
> in light of the greater detail in some of the pre-war papers on LF
> propagation they only tell part of the story. Also they are aimed at
> determining useful service area for broadcast stations and reliable point to
> point comms. Amateur communication does not exist on 'averages' but
> generally survives on peaks and rarer events. It seems true that the peak
> strengths of signals are higher in disturbed conditions but the dips are
> also lower, and there are prolonged periods of severe absorption.  It is not
> clear what his averages refer to, how long the signals are high, and whether
> there are deep fades as well.
>
> I suspect that the 'quiet' sun conditions of a solar minimum will not be as
> good as conditions when a geomagnetic disturbance is just decaying away.
> Fortunately the sun continues to produce some geomagnetic events even in
> quiet years. Quieter periods around the 11-year maximum may well turnout to
> be the best times for extreme DX on LF.
>
> Top band experience is interesting as some of the effects are common, but
> 160m propagates by the F-layer, whereas, as far as I can be sure, 136 kHz
> propages by the D-layer and at most the lowest regions of the E-layer. There
> is a lot to be learned (or re-discovered) over the next 11 years !! I do
> hope some s/w for watching Loran signals becomes available as this would be
> a powerful tool for systematic monitoring.
>
> Cheer sde Alan G3NYK
> Alan.Melia at btinternet.com