You all are talking power, implying VxI and perhaps worried about heating
effects. Another consideration is the insulation voltage breakdown point,
which another correspondent touched on. This related to the operating VSWR
of the coax.
>From the ARRL Antenna Book:
V = square root of (2xPxZxSWR)
where,
V = voltage developed in the transmission line
P = peak power in watts
Z = impedance of the coaxial cable in ohms
SWR = standing wave ratio
Using the Characteristics of Coax chart in the same Antenna Handbook, the
maximum RMS operating voltage can be read in the right column for a variety
of typical coaxial cables. RG-58 (foam polyethylene dielectric) is listed
at 600 RMS volts, RG-58 (solid polyethylene dielectric), 1900 RMS volts.
(all references from the 17th edition of the ARRL Antenna Handbook)
Hope this helps,
Steve Zettel KJ7CH
near Libby, MT USA
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