Hello,
SPICE has both models for lossy transmission line (O) and lossless transmission line (T). The .AC command gives you the frequency sweep simulation.
Before you start the simulation, you need to know the transmission line parameters that is: characteristic impedance and electrical length (or delay time). When you want to use the lossy line, you need to know the inductance/m, capacitance/m and resistance/m. You can derive that from the characteristic impedance and propagation velocity of your transmission line (except for the resistance/m).
For the simulation: Some spice programs have a network analyzer feature. If you don’t have that, you can use a current source of 1A and put a voltage probe across the current source. The voltage (phase and amplitude) equals the impedance of the transmission line segment.
If you use the lossless transmission line model , make sure to add a T or PI attenuator to model the losses of your line. When you use the lossy line, you have to play with the resistance/m to make sure the loss of your simulated line equals the actual loss. You can make a first guess based in the skin depth and size of inner conductor of the transmission line.
You can do it empirically by terminating the piece of line with its Z0 and determine the transmission (output voltage/input voltage). From there you can calculate the loss/m of your simulated line based on the length of the line.
Hope this helps you a bit.