Shielding microwave dishes from prying eyes

[Tim May]

On Friday, August 29, 2003, at 10:38  AM, Major Variola (ret) wrote:

> At 06:11 PM 8/28/03 -0700, Morlock Elloi wrote:
>> A 18-24" 2.4Ghz grid dish (available for less than $70-90) with 18-21
> dB gain
>> will associate at 11 Mb/s with consumer-grade APs with diversity
> antennas at
>> 2-3 miles.
>
> Yes; for naif readers note that the "grid" means that you don't worry
> about wind as much
> as a solid dish.  (The uwaves see the screen as solid, however.)  With
> that much gain
> (ie directionality) wind could mess with your (albeit brief) 
> connection.
>
> Its very important that you go *away* from your normal haunts if you 
> use
>
> this (esp. more than once) for attention-receiving activities.


Were I setting up such a system, I think I'd  look closely at 
installing the dishes in small plastic sheds. Small Rubbermaid plastic 
tool sheds, for example. Even an upended plastic garbage can would 
probably work well, though it might look a little odd. (Not odd enough 
to get the attention of the roving vans, though.)

If on a rooftop, where a garden shed or plastic garbage can would look 
out of place, a cylinder of light plastic (semi-rigid, not the Saran 
wrap stuff) would look like just another rooftop piece of hardware. A 
wander through a Home Depot might reveal something already made which 
would hold a 1.5 m dish very nicely.

A cylinder with an overhanging roof would like a roof vent, and would 
also shelter the cylinder walls from ice and other microwave absorbers.

I live in rural, hilly area, so I doubt any FCC vans are rolling around 
looking for (unlicensed?) directional microwave dishes. If I lived in 
any kind of urban or even suburban area, and were setting up such a 
dish system, I'd look for ways to camouflage it.

Transparency of the plastic to the specific microwaves should be 
checked, of course. Easy to check.

Detection of the dish by side-lobe leakage is harder.



> --Tim May
"To those who scare peace-loving people with phantoms of lost liberty, 
my message is this: Your tactics only aid terrorists."  --John 
Ashcroft, U.S. Attorney General