[Lf] [Fwd: LF: Fieldstrength at sunrise]

[Andre' Kesteloot]

MarkusVester at aol.com wrote:

> Hello Alan, hello group,
>
> the typical fieldstrength maximum and subsequent dip around sunrise is a very
> regular feature of ionospheric LF-signals. If it were just a coherent
> addition of two signals with slowly variing phase lag, I would expect
> different patterns depending on a random initial path length difference, and
> a time-reversed maximum-after-minimum behaviour would seem just as likely.
> This leads me to believe it is rather a quasioptical focusing-mirror effect,
> caused by the decreasing altitude of the reflecting ionospheric layers at
> sunrise. Focus and dip would then be essentially frequency-independent.
>
> This approach may be a bit simplistic, but what do you think?
>
> 73 de Markus, DF6NM
>
>   ------------------------------------------------------------
>  [Image]
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From: MarkusVester at aol.com
Subject: LF: Fieldstrength at sunrise
Date: Fri, 3 Nov 2000 17:47:19 EST
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