Originally developed for use on wind turbine towers, the TM20 tower microphones are now used in a wide range of applications. With their small diameter of just 20 mm and the three available housing variants, the microphones can not only be installed in holes in concrete tower walls using the TM20 mounting kit. In fact, the mast and magnetic bracket also allows mounting on masts and the outside of metal towers. In addition, the microphones can be installed completely watertight in openings in metal tower walls with a diameter of 25 - 58 mm using Roxtec mounting seals. Last but not least, the M3 internal thread on the back of the microphone can also be used to create your own holding devices. Together with the corrosion-resistant and waterproof stainless steel housing (IP65), the microphone capsule protection of the Plus models and the optionally configurable, seawater-resistant connection cable, the TM20 microphones are also ideally suited for offshore use.
Like all our microphones, the TM20s use Knowles' omnidirectional electret FG microphone capsules in combination with an integrated differential preamplifier. This allows cable lengths of up to 150 metres, even in an electromagnetically demanding environment. The microphone sensitivity can be monitored during long term monitorings using the integrated test signal speaker. To increase the reliability of the microphone in adverse weather conditions, a microphone heater is integrated, which greatly reduces condensation on the microphone. To prevent damage to the recording system caused by lightning, the microphones can be used together with our TM20 OVPbox or a lightning protector integrated into the BATbox.
The microphones are compatible with all BATmode systems and therefore also with the UltraSoundGate 116Hnbm and 416Hnbm from Avisoft Bioacoustics.

Notes:
In order to avoid time-consuming and cost-intensive subsequent drilling of mounting holes in tower walls, it is advisable to contact the wind turbine manufacturer before delivery of the wind turbine. In this way, appropriate drilling can already be taken into account. To reduce interference, it is advisable to position the BATbox with the recording system as close as possible to the microphone and as far away as possible from sources of interference such as power and control cables. The microphone is supplied with a 3 m connection cable for this purpose. In principle, however, it is also possible to install the BATbox at the base of the tower and use an extension of the microphone cable up to 150 metres. However, in this case a reduction in the recording quality must be expected.