Calibrations of Wide-Bandwidth Transceivers (WBT Mini) with Dualfrequency Transducers (ES38-18/200-18C) for Saildrone Surveys of the California Current Ecosystem During Summer 2018

The Summer 2018 Survey of the California Current Ecosystem (CCES), conducted by the Southwest Fisheries Science Center (SWFSC), was augmented by five Saildrones, each outfitted with a miniature wide-bandwidth transceiver (Simrad WBT Mini) configured with a dualfrequency transducer (Simrad ES38-18/200-18C). The Saildrones were assessed for their potential to enhance ship-based surveys and research. To optimize the accuracy and precision of the Saildrone-based data collections, each of the five WBT Mini and transducer pairs were calibrated. The 38-kHz three-sector split-beam channel and the 200-kHz single-beam channel were calibrated in both narrowband (CW) and wideband (FM) modes. This report describes the system characterization, calibration methods and results, and issues encountered. This report 3 also includes recommendations for software and hardware development, and refinements to calibration procedures.