[600MRG] EIRP and such

[Rudy Severns]

I think you guys need to read my recently published QEX article (Jul/Aug,
Sept/Oct) on Rr and Rg at LF-MF versus HF.  A copy of the prepublication
draft is on my web site: www.antennasbyn6lf.com
<http://www.antennasbyn6lf.com>  .   When I get a final .pdf of the
published article I'll post it but the differences are small.

 

What I argue is that, because the soil characteristics are dominated by
conductivity and LF-MF, the Rr for small antennas at LF and MF is very close
to the value for ideal ground.  The value for Rr is easily found using
either modeling or calculation.  As I show, this is not true at HF but who
cares!  We're not concerned with EIRP on 20m.

 

I argue that all you have to do is model/calculate Rr for ideal ground and
measure your antenna current.  The radiated power Pr= Io2Rr.  The EIRP for
the small antennas likely to be used by hams is simple Pr/3.  For EIRP= 5W
we are allowed Pr=1.667W.  You can also determine Pr from a measurement of
Ri and Pi: Pr= PiRr/(Rr+Ri).  

 

Besides the base article there are an extensive set of appendices with the
back-up for my argument.