On 16 Aug 2006 19:40:03 -0700, N9OGL wrote:
:
: 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
[snip]
Todd, there isn't a law you can quote which governs physics. You
can't repeal the law of gravity, and you can't logically state that
transmitter power and electric field strength are independent of one
another. Think about it: That idea doesn't even make sense.
: 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
Do you know the difference between the far and near fields? Are you
aware that an ordinary field strength meter can give you wildly
incorrect results when it is placed in the near field of an antenna?
Most engineers would tell you that you have to be at least five
wavelengths away from the antenna (and preferably ten) before you are
out of the influence of the near field. At 33 MHz, the wavelength is
roughly nine meters; therefore, your meter is in the near field of the
antenna, and all bets are off.
: 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.
Sigh. That's what we need: Electricians who never even heard of free
space impedance.
====================
God said, "div D = rho, div B = 0, curl E = -@B/@t, curl H = J + @D/@t,"
and then there was light.