[RFI] RF tight rooms - somewhat OT

[Roger (K8RI)]

On 5/12/2013 11:13 AM, Roger (K8RI) wrote:
> On 5/11/2013 11:34 PM, n0tt1 at juno.com wrote:
>> Hi Gents,
>>
>> I know a crystal radio enthusiast in CA that lives near
>> a 50KW BCB radio station.  He's been having trouble
>> making Q-meter measurements on some of his hi-Q
>> coils using a HP Q-meter.  He's been making
>> experiments with various shielding methods
>> using an AM BCB portable radio as a detector.
>> He says that the best he's found so far is aluminum
>> foil, as long as the "seal" is tight.
>>
>> To make a room that is large enough for him and a bench
>> takes a LOT of foil.  The floor, ceiling, walls, floor and a
>> good seal on a screened door would be needed for a
>> really good RF room.  The power for the room would also
>> have to be filtered or he could use a computer's UPS.  The
>> shielding would be grounded, and the shielding, whether
>> it's say, chicken wire, AL screen, etc would have to be
>> bonded together at the corners.  Then the door would
>> have to be sealed as well (maybe metal weatherstripping
>> for that?).
>>
>> My question to the group is what, in your opinion, is the
>> best/cheapest RF-tight test room he could build for himself?
>> Has anyone on this list done that?
>
>
> Many years ago, in another life, (I spent 26 years working as an
> Instrument tech, I did instrument calibration traceable to NBS.
> My work area and desk were inside a double wall screen room.  Thia was
> about 20 X 10, or 12 feet,  The door was likewise double wall, with what
> looked like large finger stock all the way around each layer. The
> "fingers were about 3/4 or 1 inch wide and maybe 1.5 inches long.  The
> door "cam locked" shit

Freudian slip!

Well that and the letters i and u are dide by side.
So are S and d  <:-))

73

Roger stuck with one handed typing (K8RI)

  with about a 2' handle on the cam.  The room was
> constructed out of panels that were ...Guessing...about 4' X 8" and 4"
> thick. Frames were either brass or bronze as were all bolts were 1/2" "I
> think".
> All electrical came in through a "filter panel" for lack of a better name.
>
> We could stand just feet apart with 10 watt HTs and still hear each
> other with the door closed, but not camed shut.  As the handle was moved
> you could watch the S-meters go down until no signal was left with the
> cam fully closed
>
> This was a commercial system. Not exotic, but very effective for an
> example.
>
> 73
>
> Roger (K8RI)
>>
>> 73,
>> Charlie, N0TT
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>
>
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