Anritsu Scorpion MS4623B Vector Network Analyzer

This is an excellent instrument with dynamic range of 125 dB.
Note that the latest ES units of Agilent's 8753 series don't go over 110 dB...

Here is a short list of useful Anritsu Scorpion resources:

Measurement Guide
Operation Manual
Programming Manual
Specification Guide
Maintenance Manual
Intermodulation Distortion (IMD) Option 13 Application Note
Dead Scorpion Recovery Procedure
Wiltron 26N50 and Others - Specification