Shazb0tThese are Spectrum Analyzers and Signal Generators. They are used for a variety of things from measuring devices such as antennas, filters, amplifiers to frequency management. These units are used a lot in spectrum management for deploying things such a wireless microphones, etc. I use mine in combination with the signal generator for evaluating filter response of home brew filters used in Software Defined Radios. You can find more here: http://j3.rf-explorer.com/