[Lf] [Fwd: LF: GW F-s versus Wx parametres]

[Andre' Kesteloot]

WarmSpgs at aol.com wrote:

>      As a broadcast engineer, I have had opportunities to observe apparent
> ground conductivity changes with temperature, and over at least some types of
> soil, there does appear to be a fairly decent correlation (if not exactly
> huge, under temperate conditions) at mediumwave.
>      The "Influence of Atmospheric Humidity on Low-Frequency Radio Ground
> Waves" article, however, is one which caused a bit of a fuss when it first
> appeared over here in The LOWDOWN.  It invokes a new cause, without any
> hypothesis for a working mechanism, for an effect that is already quite easy
> to explain.
>      One might note that some of the numbers in the article have
> pre-corrections applied that involve precisely the variables whose effects
> are supposedly being demonstrated.  Of course a "correlation" will be found
> when one does that!
>      Furthermore, the atmospheric humidity values are not known over the
> paths to the different stations whose signals are being measured...only near
> the receiving site.  It is not valid to assume the humidity is the same over
> such a wide geographical area.  (Nor is it legitimate to assume the radiated
> power of each station remains constant, but that's another matter.)
>      If one disregards the pseudomathematical circular reasoning and looks
> only at raw signal voltages, the only legitimate inference is that humidity
> levels at the receiving site have an effect on the terminal voltage at the
> receiving antenna--which is exactly what one would expect of an electrically
> short vertical atop an unprotected insulator, feeding a high impedance
> voltmeter.
>      In short, the data are meaningless.
>      For the experiment to prove the author's contentions, conditions over
> the signal paths would need to be known to at least some extent, the field
> strength would need to be measured with an environmentally protected active
> whip antenna or loop antenna, the transmitter parameters or transmit antenna
> current would need to be included, and the measured field intensities would
> need to be presented without any sort of doctoring.  In the years since the
> article's first publication, this followup has not been forthcoming.
>
> 73,
> John