RadioBanter - View Single Post

Stagger Lee

On Wed, 08 Nov 2006 11:50:55 -0500, wrote:
: One Guass governs eltrostatic and electro dynamic cases as well One
: normaly learns the the electrostatic case case first
:
: FOOLs like you don't bother to learn more
:
: but you have failed to account for the fact in any RF mattter power
: dvideds beteween the elictric and Magnetic and then the 2 regenerate
: each other (with some path loss
:
: in short you can't profrom a calution worth doing without more than
: data than you have and more equation

The result of solving Maxwell's equations for the radiated field is
that the electric field strength in volts / meter can be used to
compute the power density in watts per square meter by means of the
simple equation

P = e^2 / (120*Pi)

120*Pi is the impedance of free space, as obtained from Maxwell's
equations.

Now that happens to be a pretty complete equation, and it can indeed
be used as it stands to figure out which power density, P, corresponds
to a particular r.m.s. electric field, e. You can also solve the
equation for "e" if you want to calculate the electric field when you
already know the power density. It is a steady-state solution, and it
excludes non-radiating fields (the so-called near field), but it is
good enough for most initial calculations.

So, no, one doesn't need additional equations, and one doesn't need
to worry about power division between the electric and magnetic
fields. That's already been included in the formula given above.

: none of which matter either

They only don't matter because you have the details wrong. If we
tried to get at the radiated field strength your way, we'd never get
an answer at all.

: what matters is the measurable filed strangth

If you can't estimate the field strength beforehand, then you CAN'T
possibly come up with a good initial station design. You'd have to
put something up and hope it works out. I suspect that's exactly what
Todd has done, and it is a very dangerous way to operate.

: to determine if Todd is legal or not you MUST prefrom the test and
: till that is done Innocent till found guility is ther Law

If the calculations suggest that Todd is very probably exceeding the
legal electric field strenth (and they do), it is something that no
sane station operator should ignore. Calculations are inexpensive: A
certified field strength meter is not, and a NAL is even costlier.