RE: E-field drop off with distance (1-30MHz)

[owner-emc-p...@majordomo.ieee.org]

Dave,
 
>I assume the RF is driven into line and neutral differentially with 
>the neutral eventually connected to earth ground at the power entrance. 
>Radiation will be by common mode current. 
 
The problem with assuming everything in the house wiring is common mode,
one has to assume the light switches to every room are always ON.  Kind
of makes sleeping a problem. ;-)
 
Cheers,
 
dave garnier

        David Garnier 
e GE Medical Systems 
___________________________________________ 

                David S. Garnier 
        Senior Technician 
        PET Engineering 
        3000 N. Grandview Ave - M/S W-1250 
        Waukesha, Wi. 53188 
        Tel: 262.312.7246 
        



From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of drcuthb...@micron.com
Sent: Monday, December 15, 2003 1:29 PM
To: drcuthb...@micron.com; iain.summ...@blueyonder.co.uk;
emc-p...@majordomo.ieee.org
Subject: RE: E-field drop off with distance (1-30MHz)


I ran a quick simulation of what I see as a one story house. The RX antenna is
at a height of 1 meter. Frequency is 10 MHz and the RX antenna was moved from
1 meter to 40 meters. Ground is average Sommerfield/Norton. The E-field falls
roughly 10dB with each doubling of distance beyond 6 meters. The H-field falls
roughly 6dB with each doubling of distance beyond 6 meters. 
 
This is just a first cut. One could make a real project out of modeling and
measuring BPL. 
 
   Dave Cuthbert
   Micron Technology

From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of drcuthbert
Sent: Monday, December 15, 2003 10:07 AM
To: iain.summ...@blueyonder.co.uk; emc-p...@majordomo.ieee.org
Subject: RE: E-field drop off with distance (1-30MHz)


lain,
 
this can be calculated (I can send you the formulas) or simulated with NEC. If
you give me dimensions of a "typical" house wiring antenna I can run some
simulations and see how the e-field goes. As far as a real test, you can drive
some RF into an AC socket and take field strength measurements. One way or the
other, when you are >1/2 wavelength from the building you will be in the 1/r
region.
 
What to use for a house wiring antenna model? I assume the RF is driven into
line and neutral differentially with the neutral eventually connected to earth
ground at the power entrance. Radiation will be by common mode current. So, an
antenna model could be just a single wire to drive the common mode current on.
 
    Dave Cuthbert
    Micron Technology
 
 
 

From: owner-emc-p...@majordomo.ieee.org
[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of PLC Webmaster
Sent: Sunday, December 14, 2003 6:04 PM
To: emc-p...@majordomo.ieee.org
Subject: E-field drop off with distance (1-30MHz)


I am currently researching the radiated emissions from High Frequency Power
Line Communications (1-30MHz). 
 
I am trying to obtain information on how the e-field typically falls of with
distance. I have read books that have made claims that this is anywhere in the
rang 1/d to 1/5d. I am trying to make a statistical analysis to explain to
those who claim that in the near field it is (1/d^2) which they derive from an
infitesimally small dipole.
 
Does anyone know of any papers, experiments or actual EMC compliance
measurements in the range 1-30MHz that I could use to make an analysis of the
drop off rate.
 
Thanks,
Iain