EM-nature (was: infra-org)

coderman coderman at gmail.com
Mon Dec 9 08:07:18 PST 2013


On Sun, Dec 8, 2013 at 9:01 PM, Bill Stewart <bill.stewart at pobox.com> wrote:
> ...
> The shielding was basically plywood with sheet metal on both sides,
> with special metal joints in between them and on the corners,
> packed with wire mesh in the joints to plug any extra leaks,
> making a nice big Faraday cage.  The air vents were metal grates
> an inch or two deep with zig-zaggy airflow paths,
> and our data connections used fiber optics going through
> waveguide holes that were about 3" long and 1/8" diameter.
> Power feeds used big inductive low-pass filters.


effective attenuation of emanations above 10Ghz would be interesting.
even at >5Ghz you run into trouble with the AC filer route as you
mention; best practice seems to be DC batteries inside the cage :/

attenuation at high frequencies for air flow mesh less problematic;
optical communication links will always be useful of course...

i would be curious to see high dBm with high dBi gain
emitters(antennas) worst-case testing against actual build outs at
>5Ghz, as many designs aim for ~50dB attenuation with 120 (!!!) being
beyond exceptional..

Teletronics makes some nice 1W 5.8Ghz amps for 802.11a which could be
so purposed inexpensively.


best regards,



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