Re: [AV Media Matters] New Test Results

[rohre@ARLUT.UTEXAS.EDU]

If the melting of media was from an RF or microwave source, then it
likely
is caused by resonance of the metallic coating of the media near enough
to
the source to produce heat, or by dielectric losses causing the heating.
There are metal parts to tape media shells, and there is metallic
coating on
CDs.  I think there needs to be some research into the deleterious
effects,
and the postal authorities made aware of the losses they are causing.

Use of mu metal carriers for media will ensure that it does not receive
any
magnetic fields, and little electric field.  Also, the mu metal carrier
will
register as a dark mass on the X Ray scan.  I would hope that packing
media
with large space between the media and the outside of the package would
attenuate any fields and potential heat build up.

When we ship magnetic media, we use a three inch spacing /padding
criteria
in all dimensions, and wrap the media in aluminum foil for electric
field
shielding at least, if it is not in metal can or mu metal box.  That
came
about some 25 years ago, when some kind of random electric/magnetic
event
damaged data on some instrumentation tapes that were not isolated within
the
package sent to our lab by another lab.  Our packages are prominently
labeled with anti magnetic international symbols and DO NOT X-RAY
labels.
Of course, they are registered or sent as high priority packages.
This is only done for working copies, Masters are always hand carried in
mu
metal cases.

Stuart Rohre
Applied Research Labs

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