Richard Harrison wrote:

Some people are persuaded that resistance = loss. Not so at all.
Resistance is just a name given to the ratio of voltage to current.

If you define resistance as simply V/I with no regard to phase, then
what you say is true but if V and I aren't in phase then you have
impedance consisting of real and imaginary components - resistance AND
reactance.

Free-space has a lossless Zo of 120 pi (or 377 ohms) according to page
326 of Saveskie`s "Radio Propagation Handbook". This is a ratio which is
related to volts and amps but is actually the ratio of the electric
field strength to the magnetic field strength in an EM wave. The volts
and amps are in phase so it has the units of a pure resistance.

I suppose you could also say that a real resistor is also lossless as
the heat due to I*I*R is radiated into space and thus is not lost
Alan