OM243/OM263 Permanent Outdoor Microphone

OM243/OM263 permanent outdoor microphone is developed by BSWA Tech for outdoor noise monitor. Compared with semi-permanent outdoor microphone, the main improvement of permanent outdoor microphone is the built-in electrostatic actuator which can be used for remote system check. The internal signal source can be controlled by serial communication to generate actuating signals with 5 frequencies (250 Hz, 500 Hz, 1 kHz, 2 kHz and 4 kHz) and sound pressure level of 90 dB.

In order to avoid frequent acoustic calibration of outdoor microphone, electrostatic actuator can be used for whole system check including microphone, cable and measuring instrument. When the sensitivity and frequency response of the microphone change enough to affect the measurement, the microphone is no longer suitable for noise measurement, and it should be calibrated by sound signal or even replaced.

OM243/OM263 uses the electrostatic actuator method to apply the known alternating electrostatic force to the metal diaphragm of the condenser microphone through the electrode to push the metal diaphragm to vibrate for calibration. It can also be used to monitor the change of sensitivity. However, electrostatic actuator cannot replace acoustic calibration, and periodic sound calibration is still necessary.

The frequency response of OM243 is optimized for 0° incidence, primarily for aircraft and airport noise measurement. The OM263 is optimized for 90° incidence, primarily for urban, traffic and industrial noise measurement. Both of two types of microphones have been specially designed to achieve the free-field frequency response in specified direction of incidence within the limits of IEC 61672-1. Each microphone is supplied with an individual calibration certificate that contains the actual sensitivity and free-field frequency response data for the complete set of outdoor microphones. Users can use the calibration data to correct the measurement data for more accurate results.

OM243/OM263 meets the IP55 ingress protection rating. The windscreen, internal rain hood and dust mesh can fully protect microphone to against wind, rain, snow, dust and other severe weathers. Built-in electric heater can automatically work in low temperature and high humidity environment to avoid exceeding the working temperature range of microphone and prevent condensation. The bird spike prevents impact of perching birds to the measurement.

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