[time-nuts] Phase noise of HP8663A 640 MHz reference?

[ed breya]

Just wondering if anyone happens to know typical or an actual measured 
phase noise instance of the 640 MHz reference in the HP8663A. It does 
not seem to be specified (unless I missed it somehow), but there's an 
"option 03" that specifies it. I don't think the option provides any 
improvement, just results of an actual measurement on the particular unit.

Ed