Congratulations on your purchase of a 2706 RF Preselector. This instrument improves the flexibility and accuracy of your spectrum analyzer measurements, and is especially useful for EMI applications. Some of the outstanding characteristics of the Preselector are: Multiple filters – the Preselector has 7 bandpass filter steps covering the range from 9 kHz to 1000 MHz, and a high-pass filter covering the range from 1000 MHz to 1800 MHz. Reduced distortion – the Preselector limits potentially distorting input to a spectrum analyzer by attenuating signals outside the frequency range of interest. Increased broadband dynamic range – the Preselector increases sensitivity to low-level signals by attenuating strong signals outside the frequency range of interest. Manual or remote operation – you can operate the Preselector using its front-panel controls or a GPIB equipped controller or computer. Bypass mode – you can remove the Preselector from the testing circuit without disconnecting it. Convenient installation – the Preselector mounts below Tektronix 271X- Series Spectrum Analyzers with the optional mounting plate and rigid coaxial cable assembly (see the Parts List in Appendix D).