Charlie,
It seems to me if your friend just wants to make Q-meter measurements he
might get by with building a 5-sided aluminum box just to contain his HP
Q-meter since he is probably making measurements in the AM broadcast
band frequency range. He needs to make the box big enough to maintain
at least a coil diameter from the top of the box when the coil is
attached to the Q-meter. This won't be perfect isolation like a screen
room but it will might be good enough and a whole lot easier.
Tom W0IVJ
On 5/11/2013 9:34 PM, n0tt1@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?
73,
Charlie, N0TT
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