Stagger Lee wrote:
On 15 Aug 2006 19:40:07 -0700, N9OGL wrote:
The power in wattage and the electrical field are not related because a
power output in wattage can produce different fields depending on lengh
of coax, antenna, antenna height...and your friends in the Office of
You can't get around physics, Todd. The power density is directly
related to the electric field through an Ohm's law type of relationship,
expressed as the square of the r.m.s value of e, divided by the
impedance of free space. Once you know the power density, it is a
matter of summing that power density over the radiation pattern of the
antenna to figure out the total radiated power. Therefore, there *is* a
relationship between radiated power and field strength. In the case of
an isotropic radiator, the relationship between radiated power and field
strength is easy to calculate, and it provides one with a limiting case
which can act as a guideline.
engineering and technology at the FCC will tell you that. The antenna
I'm using is a very imefficient antenna, in fact the signal is acually
I'm not interested in your rationalizations, Todd, because I'm not the
one who is at risk. In this real world, your power output is about
five orders of magnitude larger than the power theoretically needed to
produce the maximum allowed electric field. To me, that would be a
cause for great concern.
If you want to risk an FCC enforcement action against you, be my guest.
====================
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t,"
and then there was light.
I would really suggest you read the FCC Office of Engineering and
technology bulletin on PART 15, it OET Bulletin 63
http://www.fcc.gov/Bureaus/Engineeri...3/oet63rev.pdf
expecially page 29 which states:
What is the relationship between "microvolts per meter" and Watts?
Watts are the units used to describe the amount of power generated by a
transmitter. Microvolts per meter (µV/m) are the units used to
describe the strength of an electric field created by the operation of
a transmitter. A particular transmitter that generates a constant level
of power (Watts) can produce electric fields of different strengths
(µV/m) depending on, among other things, the type of transmission line
and antenna
connected to it. Because it is the electric field that causes
interference to authorized radio communications, and since a particular
electric field strength does not directly correspond to a particular
level of transmitter power, most of the Part 15 emission limits are
specified in field strength.
So logically if you use a ineffecient antenna and ****ty coax then you
can create a low enough field....I'm tell you right now, I Have a field
strength meter that reads microvolts, and I check the field ever
morning, at it's not at no 30 meters either, it's around 17.5 meters
and the electrical field is 1,0000 uV ...So believe what the hell you
want I check it every morning and it's 1,000 uV @17.5 meters and at 30
meters it's 0. I would also point out I come from a long line of
electricians (my father, my grandfather and my great grandfather) and
THEY will back me up.