U. S. Department Of Commerce, NOAA, Central Administrative Support Center, 601 East 12th St., CC31, Rm. 1756, Kansas City, Missouri 64106

58 -- DOPPLER RADAR RECEIVER REPLACEMENT POC Charles A. Hughes 816-426-7267, ext. 229, Fax 816-426-7530 E-MAIL: click here to contact contracting office, charles.a.hughes@noaa.gov. SOURCES SOUGHT: MARKET SEARCH FOR DOPPLER WEATHER RADAR RECEIVER REPLACEMENT. THIS IS A REQUEST FOR INFORMATION (RFI) ONLY. The U.S. Department of Commerce/NOAA, National Weather Service (NWS) is conducting market research for the replacement of portions of the analog microwave receiver in its NEXRAD Weather Surveillance Radar WSR-88D. The receiver acquires and converts the radar return from a coherent doppler radar transmitter and provides digitized in-phase (I), quadrature (Q), and log channel signal components to the radar signal processing subsystem within the Radar Data Acquisition (RDA) system. The existing receiver is encountering obsolescence of critical components. Additionally, the National Weather Service is conducting a planned evolution of NEXRAD technology including addition of polarization diversity which will require a second receiver channel. Replacement of portions of the current receiver with digital components is a means of addressing these issues. The purpose of this RFI is to gather information from digital receiver manufacturers relating to the availability of components in the commercial market. The following are the salient characteristics of the existing receiver. The receiver channel consists of the following components: receiver protector, interference filter, low noise amplifier, pre-select filter, mixer (STALO), pre-amplifier, matched filter, automatic gain control, IF amplifier, phase detector (COHO), and analog to digital converter (A/D). The input RF range is from 2700 to 3000 MHz. The intermediate frequency (IF) is 57.5491 MHz. The input signal dynamic range is 93 dB minimum. The first mixer output signal power is -76 dBm to + 19 dBm. Output impedance (to A/D converter) is 50 ohms. A/D conversion rate: 600 kHz. The current receiver contains extensive automatic calibration state determination and built-in-test (BITE) diagnostics. Desired features of replacement digital receiver subsystems are as follows. Noise Figure: less than 18 dB. Input digital dynamic range: 105 dB minimum. Signal input impedance: 50 ohms. Input signal carrier frequency (IF) 57.5491 MHz. Input signal power -76 dBm to + 19 dBm. A/D conversion rate: 600 kHz minimum. Input COHO frequency: 57.5491 MHz. Input COHO power: up to +27 dBm. In phase and quadrature signal output: 18 bit, 2's compliment/ 18 bit custom code. I/Q amplitude imbalance: 0.25 dB maximum. I/Q phase quadrature imbalance: +/- 2 degrees maximum. The custom output data must be compatible with the custom format to the signal processor which is as follows. The I and Q outputs are a custom code with the sign bit and 11 least significant bits sent serially. There is an additional 6 bit parallel output which is the automatic gain control (AGC) attenuator position information. This information is used by the signal processor pre-scaler to scale the data in accordance with the AGC attenuators. GENERAL: The National Weather Service desires to replace as many of the current analog components of the radar receiver as practical, given the current state-of-the-art in digital receiver technology. Responses to this market survey must include the device manufacturer, a product description with performance parameters, and a statement regarding current availability (NDI, prototype, in production, fully developed but not in production) and estimated cost of the product. This RFI does not constitute an Invitation for Bids, Request for Proposals or Request for Quotes. Should the results of this market research indicate feasibility of replacing portions of the analog receiver with existing commercial products, the NWS will consider retrofit options for its nationwide network of 175 RDAs as a potential follow-on product improvement project. This is not a request for proposals and there is no solicitation available. Information should be sent to the attention of Charles A. Hughes, U.S. Dept. of Commerce/NOAA, Acquisitions Branch, 601 E. 12th Street, Rm. 1756; Kansas City, MO 64106. Posted 04/07/99 (W-SN317271). (0097)

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