TFA Dostmann 30.3030.IT Livret D'instructions page 39

4. Neighbors using electrical devices operating on the 868 MHz signal
frequency can also cause interference.
Note:
When the 868MHz signal is received correctly, do not re-open the battery cover of
either the transmitter or Temperature station, as the batteries may spring free from
the contacts and force a false reset. Should this happen accidentally then reset all
units (see Setting up above) otherwise transmission problems may occur.
The transmission range is about 100 m from the transmitter to the temperature
station (in open space). However, this depends on the surrounding environment and
interference levels. If no reception is possible despite the observation of these
factors, all system units have to be reset (see Setting up).
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