Department of Commerce, Mountain Administrative Support Center, Procurement Division, MC3, 325 Broadway, Boulder, CO 80303-3328

59 -- PRESELECTORS The National Telecommunications and Information Administration (NTIA) is seeking information on components which would be suitable for a van-deployed RF interference measurement system. The system design has not been completed, so the following requirements are not absolute and are open to input. The following describes requirements for a tracking YIG and varactor preselectors to be used in the RF interference measurement system. The system is intended to function as a front end/preselector/preamplifier to a spectrum analyzer. The preselector may be of two types: a YIG-tuned preselector operating over approximately the 0.5-18 GHz range, and a varactor preselector operating over approximately the 0.1 - 500 MHZ range. NTIA is also very interested in exploring the possibility of extending the upper frequency range to 26 GHZ. The preselector(s) must automatically track a tuned frequency from a spectrum analyzer. The YIG and preamplifier will be remotely located in an antenna tower box; the varactor will likely be located within the measurement van. The tracking must operate without a computer system to provide tuning information, presumably by using the ''tuned frequency'' output of the spectrum analyzer. The control voltages for both preselector and varactor shall be derived from the following sources: spectrum analyzer tuned frequency output (primary), front panel tracking adjustments (to provide for calibration or adjustments), and computer programmed DAC tuning over an IEEE-488 bus. Additionally, the preselectors must be capable of operating with the spectrum analyzer in stand-alone mode, free from computer busses or other instrumentation. NTIA is interested in exploring both the standard dual YIG configuration and also the configuration of the YIG preselector as a dual two-ball YIG with an intervening preamplifier. This configuration is desired to enable the operator to continuously monitor the tracking of the pre and post-amplifier balls and instantaneously adjust for optimum tracking by maximizing the noise floor observed on the spectrum analyzer. It is preferred that a single YIG and preamplifier cover the 0.5 to 18 (26) GHZ range but not required. The system will use noise diodes with 25 dB excess noise as a basic amplitude calibration and diagnostic tools. These diodes are to be located in the antenna tower, in order to calibrate the system gain up to the antenna switch. Any components supplied must be supported over the lifetime of the system (expected to be 10 - 15 years). Information should be submitted to John Mastrangelo, NTIA/ITS.S1, 325 Broadway, Boulder, CO 80303-3328. Please contact John Mastrangelo on 303/497-3485 if you should have any questions. (0059)

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