I have some RG-9/U that sounds very similar (double silver shield, etc.)

Jay in the Mojave wrote:

Hello All:

Looking for a few hundred feet of RG393 coax.

This a coax about the same size as RG213, 9913, or LMR400 but has a
silver plated stranded center wire, with Teflon dielectric and a double
silver plated shield.

Working a old aircraft restoration project. So also interested in cable
clamps.

Jay in the Great Mojave Desert