GF 1

Primary use:


Polar patterns:

Common name: Microtech Gefell GF 1

Production Status: In production

The boundary layer GF 1 and the weatherproof power supply unit WN 1 are specifically developed extensions in order to record the sound emission of wind power stations with measuring microphones pursuant to DIN EN 61400-11. Due to the operation near the ground, unwanted influences of the measurement results by reflections of the ground are avoided. The low wind speed near the ground also has the effect of reducing the wind noise at the microphone. The The GF 1 primary and secondary windscreens ensure a broadband reduction of the induced wind noise at the microphone of 40 dB. Due to the acoustic effect of the sound-reflecting boundary layer, the microphone sensitivity increases by 6 dB as inherent to its functional principle. Thus, an overall improvement of the signal-to-noise ratio of approx. 46 dB can be achieved. As measuring microphone element, class 1 measuring microphones are suitable, which consist of measuring microphone cartridges with a frequency range from 20 Hz to a minimum of 10 kHz, a dehumidifier adaptor and a measuring microphone preamplifier with 200 V or IEPE supply. The WN1 is a weatherproof power supply unit with the measuring microphone power supply unit MN 921. It provides an operating voltage for conventional measuring microphones (7-pin LEMO®) as well as for IEPE measuring microphones. It can be operated with accumulators, batteries or mains voltage. The amplification of the microphone signal can be set using a rotary switch. The integrated line driver allows a transmission of the microphone signals over a cable length sufficient for measurements on wind power stations. The structural design of the GF 1 allows a simple calibration with a sound calibrator. With the impregnated secondary windscreen, the ground plate coated with varnish and the weatherproof power supply unit, GF 1 and WN 1 form a weatherproof system for the standard-conforming sound emission measurement of wind power stations. Includes GF 1 with ground plate (demountable in three parts), primary windscreen W 2.1, secondary windscreen W 450, 1100 x 510 x 405 mm suitcase.

Electrical Characteristics

Frequency Response
20Hz - 10 kHz
Output Sensitivity
Self Noise (CCIR)
Self Noise (DIN/IEC)
Output Impedance
Recommended Load
Proprietary unit
Supply Current
Alternative Powering

Switchable Options


Physical Characteristics

Lemo 7-pin
Connector notes
Available Colours
15000 g
Min diameter width
Max diameter


Ground plate (demountable in three parts), primary windscreen W 2.1, secondary windscreen W 450, 1100 x 510 x 405 mm suitcase.