AM alignment generators like that EICO ( which will work for marker generator in sweep/marker TV alignment with an additional RF sweep generator) tend to have very non-sinusoidal waveforms...which helps with radio alignment...the distortion makes the modulation detectable to FM radios and eliminates the need for a dedicated generator for FM...those waveforms can boggle some frequency counters into giving false readings....I have an older HP pure sine wave generator that lacks modulation so if I need to know precise frequency from my modulated tube Heathkit alignment generator I connect it to a scope, count divisions a cycle takes, hook the HP to the scope and dial it to the same number of divisions and then hook the HP to my frequency counter...the reverse can be used to set the Heathkit...
I'm a fan of finding (needlessly) complex ways of circumventing limitations of my test equipment.
