[Boatanchors] Tube shields

Michael k3mxo.hi at gmail.com
Sun May 25 20:12:58 EDT 2014

Note that the only good ones are the IERC shields made to MIL-S-9372 specs.
Of those, only the ones which were made on alternate Tuesdays that coincide
with a new moon between the hours of 7:14 AM and 1:23 PM are worth having.
The others made to this spec resonate imperceptibly at frequencies between
516 Hz and 2.16 kHz.  This resonance is impossible to see on any test
equipment.  Only a true expert's ear can hear it.  Other IERC shields also
have resonance issues, mostly at negative frequencies which cancel out the
positive counterparts in music thus leaving the music sounding hollow and
unfulfilled.  Non-IERC shields sound metallic and aren't worth the metal
they're made from.

Best Regards,
Michael, K3MXO, CBLA #6, BL01hx15np24 ... or there abouts  
What was the greatest thing before sliced bread?
Hiki Nô! 

-----Original Message-----
From: Boatanchors [mailto:boatanchors-bounces at puck.nether.net] On Behalf Of
Brian Carling
Sent: Sunday, 25 May, 2014 13:44
To: Bob Jackson
Cc: porch.boat; puck.boat; qth.boat
Subject: Re: [Boatanchors] Tube shields

I have a bunch of the black ones if anybody is interested...

Best regards - Bry Carling

> On May 25, 2014, at 6:48 PM, "Bob Jackson" <bob145 at suddenlink.net> wrote:
> I always assumed that tube shields were used to keep stray RF either in or
out of the tube or both. Are there other reasons as well like keeping them
securely in their sockets via the little springs inside the shield?
> Bob
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