Good explanation bob. After saying something, I started to wonder exactly
how much steel was in a house. Probably varies depending on the builder.
"Bob McConnell" wrote in message The only
effective RF shield is a continuous metal grid on all sides,
top and bottom. It is called a Faraday cage. So, if you have a metal
layer in both the subfloor and ceiling, and all of those studs are
electrically connected to them and each other, and you install metal
cross braces every 16", you would reduce the strength of all signals
below about 300 MHz, so channels 7 to 13 might have more snow than the
neighbors do, but 2-6 and FM would be much weaker. The commercial AM
band would be much weaker still, which might not be a bad idea.

For any one interested in the theory, a wire mesh screen will reflect
signals whose wavelength is longer than twice the size of the space
between the wires. Twice 16" would be 32 inches, just less than one
meter. For a wavelength of 1 meter, the frequency is 300 MHz. The
reflection is not total, and the change is not instantaneous, but
gradually becomes exponentially stronger as the frequency drops. At
300 MHz, the signal would be half reflected. at 150 MHz about 3/4,
etc. FM broadcasts are grouped around 100 MHz, between TV channels 6
and 7. AM is way down at 1MHz.

On the other hand, a steel building sitting on the ground pretty much
blocks everything.

Bob McConnell
N2SPP