Am I correct that I need to use the sum weight of the steel rod and the weight of the uniform load to calculate the total load on beam (W)?
https://engineersedge.com/beam_bending/beam_bending1.htm
I ask because the calculations do not seem to be correct using a load of zero (so only the weight of the rod) or very small loads like 1 or 2 lbs for a large span.
The purpose is for a 1.5" diameter steel curtain rod that needs to span 232" supported only on both ends, not in the center. The curtains will weight 2 Lbs in total, and so the deflection in the center with this uniform load will be mainly with the weight of the steel rod.