"But for most sources, the transition from
near to far field occurs at roughly 1/6 wavelength"
I don't believe sources I cited not a month of two back
are in agreement with that statement NOR does it
agree with the empirical results that those using
shielded magnetic loops experience (which I had
just alluded to in, I think, my previous post.)
I will provide those sources again this evening when
I've got more time.
As to your contention that a measureable amount of
noise, from man-made incidental radiators, can create
S4 levels of noise, say, 100 miles distant, even
considering cumulative effects (that is, many sources
adding together to create 'the noise') I cannot at this
----- Original Message -----
From: "Jim Brown" <firstname.lastname@example.org>
Sent: Thursday, August 10, 2006 12:18 AM
Subject: Re: [RFI] [BULK] Re: Ambient Noise Levels
> On Wed, 9 Aug 2006 23:37:54 -0500, Jim P wrote:
> >I don't know that I entirely agree with that statement of
> >the origins of the noise, however.
> Of course the noise at any location will be the sum of noise
> from many sources, some of them local, some of them distant. A
> few of those that are local may be close enough to be in their
> near field. But for most sources, the transition from near to
> far field occurs at roughly 1/6 wavelength, so at HF and above,
> most noise sources that aren't in our own home are far field
> sources. I live and work in the pro audio world, where virtually
> all of our baseband noise sources are power-related magnetic
> sources, and our systems are in their VERY near field.
> My point, and Tom's, is that once you've cleaned all the local
> noise out of your QTH and leveled your neighbors's homes, you're
> still left with skywave.
> Jim K9YC
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