[TowerTalk] Heliax question

[Paul Christensen]

>"This one I haven’t been able to identify is (as closely as I can measure
with a tape measure) 1/8” larger over the dielectric than the 7/8”. "

Stan,

Is it possible you have a roll of 75-ohm cable?   When I was employed by
AT&T Broadband, in some instances we used Commscope 1-inch corrugated
coaxial cable with a solid inner and foam dielectric.  You could get a rough
idea by applying the simpler formula: Zo=138 × log10(D/d), or better still,
with a cable that long, use a VNA and get a S11 measurement by alternating
between 75 and 50-ohm terminations.  

Paul, W9AC