[RFI] [BULK] Re: Ambient Noise Levels

Tom Rauch w8ji at contesting.com
Sat Aug 12 00:16:41 EDT 2006


Let's deal with one basic useful fact at a time.

 > Time varying fields.
> Tell me, can a magnetic field penetrate a copper sheet?

Certainly, as long as it is static and not time-varying at 
high frequencies. Once the sheet is several skin depths 
thick, the answer is no.

>> of about 1/8th wave, a magnetic loop is electric field
>> response dominant! It's only right next to the antenna it 
>> is
> Proof?
> I've got proof to the contrary:
>     http://www.emcesd.com/pdf/emc99-w.pdf

I'm not sure if Smith doesn't understand what the shield is 
doing or didn't explain it well.

> Until you can provide some measurements, Tom,

I already did, it's on my website at the link I posted.


> going to have to side with the guys who have actually
> used and seen the practical, useful, proven utility of the
> loops for the reasons they cite.

I'll side with Maxwell, Lentz, and Faraday and all the 
engineers I've worked with over the years.

> Still no cite from one of you guys to support this, just
> continued assertions.

Reference Data for Radio Engineers, ITT Books, Chapter 29, 
Radio Noise and Interference.

 That's a peer reviewed technical reference publication, not 
a personal paper or non-reviewed article.

Anyone interested in noise should get that book if they find 
it someplace.

The fact weak distant noises accumulate is exactly why the 
ARRL is so worried about BPL. It will affect everyone, not 
just those near the BPL sites.

73 Tom 

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