This work compares the random time-varying crosstalk in homogeneous multi-core fibers measured using different types of light sources with linewidths ranging from 100 Hz to 2.5 MHz. We show that the frequency stability of the light source plays a significant role on the quality of short-term average crosstalk measurements with no observable impact from laser linewidth. We also compare the use of filtered amplified spontaneous emission noise and coherent light sources for crosstalk measurements. The former are shown to enable average crosstalk measurements in short time periods. In contrast, measurements using coherent light sources require long measurement periods to reach similar results.