Looking for special resistive coax

We need a source for coaxial cable with a resistive center conductor, similar to the coax supplied with the Tektronix P6015A high voltage probe. A few years back we purchased several custom lengths from Unitrek corporation
which has since been sold (twice). I can't seem to get any response from the new company..

This cable is slightly smaller in diameter than RG58, has about 50 ohm, 6pF/ foot resistance/capacitance.

Anyone know of another source for this type of special application cable ?

Hi,
Did you asked Belden Cable, & Tek itself pls?
K.