You made great interesting experiments!
The electrical field will suffer with a alumni foil, surely. Magnetics will
go thru.
- Henry

Arie de Muynck schrieb in Nachricht
...
"Henry" wrote ...
Why not in metal can? You can use for example alumina. But no
ferroelectrics! (If it's a magnetic antenna)

Arie de Muynck schrieb in Nachricht
Great, an antenna working even if cast in metal....


Lookup eddy currents, skin effect depth, etc.

Placing an antenna in a _closed_ conductive box is not the best way to make
an efficient antenna. Only if the box has a slot the energy may seep though
that - but that's not in "Our tiny antenna can be placed in the car or cast
in metal, and is at least as good". I see casting in metal as a closed box.
The antenna will be shielded unless they use VERY slow changing signals.
Not
good for efficiency either.

Take a working old MW transistor radio with ferrite antenna and wrap it in
Alum foil. Make sure the edges make contact. You may puncture small holes
to
hear the sound - or rather, notice the lack of it.

Arie de Muynck