[Lowfer] WM too bright!

[Bill Ashlock]

John A,

I'm confused. Are you sure that the higher readings at various measuring 
sites in the winter weren't due to improved efficiency of the transmitting 
antenna (a local effect) and had little to do with the soil conductivity in 
the far field?

Bill A

> >some
> > broadcast engineers attempting to measure soil conductivity in the AM 
>band
> > by means of signal attenuation noted that their conductivity results 
>came
> > out on the high side during very cold winters.
>
>Amen. The difference can be impressive. Over the lousy ground here in the
>Northeast, smart AM guys see that their initial field strength measurements
>are made in the winter. That way, when the FCC sets the limits on their FS
>monitoring points, the station should be safely under them all year.
>
>That said, AM field readings can vary dramatically with temperature over a
>time frame that's much too short to be explained by the ground, trees, or
>anything but the air. I've never seen a convincing explanation of that
>effect. But I've observed days in January where the weather was balmy in 
>the
>morning and very cold in the afternoon following a frontal passage, and
>local AM field readings went right up with the temperature.
>
>John A.
>
>
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