[TowerTalk] Screened walls and floors

[Roger (K8RI) on TT]

It was a double wall screen room
With 5W HTs a foot apart, one inside, one outside, caming the door shut 
took them from overload to being undetectable.

At the time (before I quit and went to college) I did the RFI 
measurements and instrument calibration for the plant. The signal 
strength measurements were done with a Singer Metrics receiver. The 
isolation was beyond its ability to measure.

73

Roger  (K8RI)


On 12/5/2016 8:08 PM, jimlux wrote:
> On 12/5/16 1:06 PM, Roger (K8RI) on TT wrote:
>> When I was a tech my desk was in a double wall commercial screen room.
>> The screen was Copper. The door shut into a frame lined with heavy
>> finger stock.  The door latched using a cam.
>>
>> Commercial screen rooms do use copper screen.
>
>
> Indeed - http://www.ets-lindgren.com/iDEI-Screen
>
> I wonder, though, what the attenuation of that is vs the solid panels.
>
> Screen - double layer electrically isolated
>     Magnetic (14 kHz): 68 dB
>     Electric (14kHz): 120 dB
>     Planewave 450 MHz: 110 - 120 dB
>     Planewave 1 GHz: 90 - 110 dB
>     Microwave 10 GHz: 50 - 80 dB
>
> vs a solid (Lindgren type 81) single layer
>
> Magnetic Field
>
>     20 dB @ 1 KHz
>     56 dB @ 10 KHz
>     100 dB @ 200 KHz
>
> Electric Field    100 dB from 200 KHz
>     thru 50 MHz
>
> Plane Wave    100 dB @ 50 MHz to 1 GHz
>
> Microwave     100 dB @ 10 GHz
>
>
> So it looks like a single layer screen is not as good as a single 
> layer solid..