All depends on the starting point data which may not be easy to obtain.


For EXACT classical calculation of loss along coaxial, solid polyethylene
insulated lines for given conductor dimensions, for any terminating
impedance, any SWR, from power frequencies to UHF, download program COAXPAIR
from website below. This program may be used to check accuracy of
simplified formalae available in handbooks.


For power and voltage ratings and temperature rise above ambient, download
program COAXRATE. Information is much better than is generally provided by
manufacturers.


Approximately, at HF,

Attenuation = 4.34*R/Zo decibels per metre.

Where R is the HF resistance per metre of the inner plus outer conductors
and Zo is line impedance.


R = Sqrt( F.MHz ) * ( 1/d + 1/D ) / 12 ohms per metre.


Where d = inner conductor diameter, mm

and D = outer conductor inside diameter, mm

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Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
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