Peter Peres wrote:
>>
........
>>The sticker says 55-60 dB attenuation at 30-2000 Mhz. Is the energy
>>absorbed or reflected back inside? The case is certainly not spongy.
>
>
>Both. Nothing is prefectly reflecting, or perfectly absorbing, but I
>suspect it's more reflective than it is absorptive.
>High resistances would indicate absorptive to me.
>The ideal material would have a gradient of impedances arriving at near
>zero for the outer wall.


Actually, as I loosely determined by poking with my DMM, the
outer surface of the case has very low conductance, >10 Mohm.
However, poking the edges of holes cut thru the case, you get
readings around 20+ ohms. So, would seem this is like
1/[your ideal material]. Gradient is infinite on outer/inner
"surfaces" - with low Z inbetween.
============


>All the RF would then (in theory) be converted to heat, which is still
>legal to radiate.
>
>Somehow, it seems like cheating to upconvert all the noise beyond the FCC's
>reach in the spectrum though :)

Guess they trap the heat inside the box after all, rather than radiate
it. Hmmm, box is black - must mean something - heat eventually
"conducted" to outside surface, then radiated.

- danM

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