Lech Laszkiewicz wrote:

I wonder why a very highly professional designers of the Decca system went
to the expense and complexity of copper sheet screening of the interior of
their complete buildings containing the antenna tunung/loading coils.

We visited the "coil" room of the Annapolis, Maryland VLF transmitter (NSS),
and the ceiling, floor and all the walls were also covered with copper sheets
73
Andre' N4ICK