[Lf] [Fwd: LF: Re: Sunspot Cycle & LF]

[Andre' Kesteloot]

Vernall wrote:

> Jim and others,
>
> > The graphs in Terman show only a modest 3-4 dB variation in
> > signal level over the sunspot cycle - but what they don't show is
> > what the signal-to-noise ratio was. The high noise level on LF is
> > one of the major factors deciding if communications can take place
> > or not. If a lot of the background noise on the band is from distant
> > electrical storms, one would expect the noise level to be subject to
> > the same propagation effects as the signals are. It could go either
> > way I suppose, so I await the solar minimum with interest.
> >
> > Cheers, Jim Moritz
>
> As an anecdotal comment, in ZL, when we started on LF in the early 1990s,
> the DX propagation seemed to be better than it is now.  We were doing quite
> well for DX, and first-built transmitters were generally lower power than
> are used nowadays.
>
> I've also had a look at ITU-R propagation graphs, but they are confusing to
> interpret as they are normalised.  As somebody else commented on, the thrust
> of some ITU-R work is to determine reliable ground wave coverage for LF and
> MF broadcast stations, and the likes of sporadic transcontinental DX is not
> in their terms of reference for results.
>
> My opinion is that LF DX is statistically better around a sunspot minimum,
> late at night, in winter.
>
> 73, Bob