[ARC5] Ceramic insulator beads

[J Forster]

Hi Mike,

I have them in packages of 10 and 12 and 100 in a small tube box (none are for sale). The box of 100 is date coded 1952.

Very similar beads are still made for insulating high temperature heater wires . I checked and posted the info a few years ago, including part numbers and sources.

I think the purpose of the beads was to prevent human contact w/ the Tx antenna wires to avoid RF burns more than to actually insulate the wire. Also, it does make sense because the beads might well be less susceptible to corona problems than insulated wire at
reduced atmospheric pressure.

Best,
-John

===========

Mike Morrow wrote:

> It seems to me that the use of many individual beads strung on a wire was a bad idea.  I wonder how often a bead-covered lead broke or came loose from an antenna terminal and dumped scores of the beads into the bottom of the airframe.
>
> Bead use seems to have been a USAAF custom.  I don't recall seeing any pictures of USN installations using the beads, nor manuals calling for their use.  The USN seems to have been content with using appropriately insulated wire.
>
> Still, for historical restoration, one has to go with what was used, no matter how impractical it was.
>
> William Donzelli ("toober" on ebay) once had supplies of IN-33 insulator packets that he sold or auctioned.  I don't know how many beads were in each packet...it didn't look like all that many, so many packets of beads would be required in a typical installation.
>
> Mike / KK5F
>
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