George Fliger wrote in a message to Lawrence Garvin:
 GF> RG-8/U used to be used for CB base station setups and is
 GF> closer to the 50-ohm standard than the RG-58/U used for
 GF> mobile setups (closer to 52-ohms).
RG-8 and RG-58 have identical nominal impedance.  The difference is that RG-8 
has a thicker dielectric and is therefore capable of handling higher power 
levels and voltages.  This would be important in a radio transmitter, but not 
at CB power levels or in networks.  RG-8 was often used in radio because it 
tended to have lower loss when cables had air dielectrics, but this is not 
much of an issue these days with moderm foam dielectrics.
 GF> There are differences between the /U and regular cable types
 GF> (just for general info) but you'd be surprised how many
 GF> setups I've found that had segments of /U cable in with the
 GF> accepted cable types for networking. :) ... and they
 GF> wondered why they had connectivity problems!
All RG series cables had the "/U."  The suffix letters indicated the version 
of the specification with which the cable complied.  That is, RG-58A/U would 
have tighter specifications and tolerances that RG-58/U.  In some cases, the 
later versions of the cables also had non-contaminating jackets or other 
special features.
-- Mike
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