Model 865 | Do I still need to order a Low Noise option on the 865 ? 

The Model 865 is a new product for 2018. The 1 GHz phase noise is extremely low in the standard unit (-87 dBc/Hz @ 10 Hz offset ). For even more demanding applications, we can install a special Low Noise option as in previous models. We believe the performance of the 865 with LN option is the market leading signal source in this class. (-100dBc/Hz @ 10 Hz offset)