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

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

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