Today the beat frequency was very difficult to find. Something changed, and I am not sure yet how to drive
the frequency of the beat. However the beat frequency is at 50MHz while so far it was at 64MHz. The PLL lock
more difficult and noisier.
Sometimes today or Yesterday we have increased the temperature of the lab (~ 2 degrees F).
lab computer/control fb2/home/data/20151016_PLL_noise_50MHz