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Re: [IRCA] Max. Groundwave Propagation Distance?--Thanks!
- Subject: Re: [IRCA] Max. Groundwave Propagation Distance?--Thanks!
- From: Russ Edmunds <wb2bjh@xxxxxxxxx>
- Date: Mon, 10 Mar 2008 04:03:51 -0700 (PDT)
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--- "Jeff T. Casey" <ne2j@xxxxxxxx> wrote:
> However, since surface conductivity (and resistance) presumably do
> not change significantly over time (except when it rains or floods?),
> it would seem that a signal arriving only via groundwave should come
> in either 24/7 or never (assuming no changes at the transmitter
> site). So, I would think that a signal that is heard at noon on some
> days but not others must be arriving via skywave
> only, but maybe I'm neglecting some important factor.
>
>
There can be a significant difference in ground conductivity in a given
area between when the ground is dry and hard, and when it is very wet
an flooded although maximum effect occurs when the gound is staurated.
A similar effect occurs when the ground is snow-covered.
When a signal isn't rock-steady at the same time day to day that is
usually indicative of skywave involvement unless we're speaking of a
water path or mostly water path.
Russ Edmunds
Blue Bell, PA ( 360' ASL )
[15 mi NNW of Philadelphia]
40:08:45N; 75:16:04W, Grid FN20id
<wb2bjh@xxxxxxxxx>
FM: Yamaha T-80 & Onkyo T-450RDS w/ APS9B @15'
AM: Hammarlund HQ-150 & 4' FET air core loop
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