Aluminium..Copper... Coil Screening

[pwdrive]

Should work, as long as it is similar thickness (well, minimum 60% of the aluminium thickness strictly).

Conductors work as screens because any changing magnetic field causes eddy currents which cancel the field on the remote side of the screen. As long as the screen thickness is a fair bit more than the skin depth at the frequencies of interest, it'll work well.

Thanks kalee, I am thinking of using copper foil, it's for the shortwave Regenerodyne project that hopefully I will be working on again once the new workshop is finished, I want to do away with range switches if possible so the idea is to make each coil range as a plugin unit similar to that used in the HRO, my metalworking facilities are limited so I want to make the coil pack enclosure box in thin plywood with plywood compartments seperating each coil the created compartments will be lined with copper foil as it is easy to solder the various sections of the copper lining together and earth them, the front panel of the coil pack will be aluminium and also be earthed I can get thin phosor bronze strip to make the chassis side of the contacts, these will be arranged as individual contacts over the top of the plugin coil pack mounted on a composite bar of paxolin or some such material, the contacts on the actual coil pack will be plated studs/rivets etc. which will protrude at the correct hieght from the top of the coil box to make contact with the phosphor bronze spring contacts. If copper foil is not suitable I have an old copper hot water cylinder I can cut to get copper sheets out of.
All subject to change of course..

Lawrence.