OM242/OM262 Permanent Outdoor Microphone Class 1

    OM242/OM262 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 of the microphone. The external excitation signal source that can generate sine wave signal with frequency of 500 Hz and amplitude of 210 Vpeak ~ 280 Vpeak (about 150 VRMs ~ 200 VRMs) can excite the microphone generate 90 dB@1 KHz output signal. Electrostatic actuator can be used for whole system check including microphone, cable and measuring instrument, but it cannot completely replace the sound calibration. Therefore, it is still necessary to use sound calibrator for calibration regularly.

    The frequency response of OM242 is optimized for 0° incidence, primarily for aircraft and airport noise measurement. The OM262 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.

    OM242/OM262 meets the IP54 ingress protection rating. The 90mm windscreen, internal rain hood and dust mesh can fully protect microphone to against wind, rain, snow, dust and other severe weathers. The bird spike prevents impact of perching birds to the measurement.

★NOTE: The generation of the signal required by the electrostatic actuator needs to be realized by the circuit designed by the user. If the user lacks relevant knowledge, please directly purchase the permanent outdoor microphone OM243 / OM263 with built-in signal generator.


  Optimized for 0° and 90° incidence to meet IEC 61672-1

  Delivered with individual calibration data

  IP54 enclosure to against rain, dust and perching birds

  The protection kit can be quickly remove for calibration

  Built-in electrostatic actuator for remote system check (external excitation signal source is required)

  ICCP power supply, low self-generated noise, typical noise level is ~17 dBA

  It can be installed on the tripod by 1/4-inch thread on the bottom


  Aircraft and airport noise measurement

  Urban, traffic and industrial noise measurement

  Acoustic measurement in severe weathers





Aircraft and airport noise

Urban, traffic and industrial noise




GB/T 3785.1-2010 Class 1, IEC 61672-1:2013 Class 1, ANSI S1.4-1983 Type 1

Built-in Microphone

1/2” Prepolarized Microphone

Sound Field


Sensitivity@250 Hz (mV/Pa) (±3 dB)

50 (-26 dB re 1V/Pa)

Polarization Voltage

0 V (Prepolarized)

Frequency Response (Hz)

10 ~ 20 k (According to IEC 61672-1)

Dynamic Range (dBA ~ dB)

17 ~ 134

Self-generated Noise (dBA)


Maximum SPL (dB)

≥ 134 (3 % distortion)

Peak SPL (dBA)


Output Impedance

< 30 Ω

Maximum Output Voltage (Vpeak)


Power Supply

ICCP (2 mA ~ 20 mA, 4 mA Typ.)

Output Connector

BNC (Microphone), 10-32 UNF (Actuator)


Optional, IEEE 1451.4 compliant (default v0.9, optional v1.0)

Mounting Thread for Tripod

1/4” thread


IP54 (Microphone vertical placement only)

Operating Temperature Range (°C)

-30 ~ 80

Operating Humidity Range (%RH)

0 ~ 95

Dimensions (mm)

Ø90 x 222 (without extension rod), Ø90 x 376 (with extension rod)

Weight (g)

94 (without extension rod), 214 (with extension rod)

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