Operates with the 8566B and 8568B spectrum analyzers Reduces overloading from out-of-band signal Improved system sensitivity Built-in transient limiterThe 85685A RF preselctor is designed to operate with the 8566B and 8568B spectrum analyzers. The RF preselector adds tracking filters to reduce overloading from out-of-band signal and preamplifiers for improved system sensitivity over the 20 Hz to 2 GHz frequency range. The 85685A RF preselector has two input, 20 Hz to 50 MHz and 20 MHz to 2 GHz. There is also a bypass mode which is DC to 18 GHz. Input 1 has a built-in transient limiter for protection from transients generated by line impedance stabilization networks (LISN). The preselector is fully programmable over the GPIB.