Abstract: This report describes the methodology and results of an investigation into the source, mechanism, and solutions for radiofrequency (RF) interference to WSR-88D Next-Generation Weather Radars (NEXRADs). It shows that the interference source is nearby base stations transmitters in the Broadband Radio Service (BRS) and the Educational Broadband Service (EBS) and that their out-of-band (OOB) emissions can cause interference on NEXRAD receiver frequencies. The methodology for determining interference power levels and mitigation solutions is described. Several technical solutions that can mitigate the problem are shown to be effective. Trade-offs between effectiveness, difficulty, and costs of various solutions are described, but it is shown that there is always at least one effective technical solution. The report shows that careful planning and coordination between communication system service providers and Federal agencies operating nearby radars is important in the implementation of these interference-mitigation techniques. A number of the report's interference mitigation options have already been implemented in several United States cities served by a BRS/EBS licensee, at licensee WiMAX stations where NEXRAD radar operations are located nearby. As of the date of this report's release, interference from the licensee's WiMAX links to NEXRAD receivers in those markets has been successfully mitigated using the techniques described herein.
Keywords: airport surveillance radar (ASR); electromagnetic compatibility (EMC); interference-to-noise (I/N) ratio; NEXRAD; out-of-band (OOB) emissions; radar interference; radio frequency (RF) interference; WiMAX; WSR-88D
The full report is available at http://www.its.bldrdoc.gov/publications/2684.aspx