On the unlicensed 869 MHz frequency band, there is a limitation in the duty cycle in Europe. Without Listen Before Talk, the channel can be used for transmissin for only 36 seconds per 1 hour (1% of 3600 seconds). If a weather station wants to send its measured value every second, this leads to a 10 ms transmission and 990 ms pause.
Calculation for a LoRa module with the following parameters
Frequency: 869 MHz
Transmission power: 14 dBm
Spreading factor: 12
Bandwith: 250 KHz
Data volume per telegram: 6 including CRC
TX: approx. 10 seconds
Pause (no RX): approx. 990 seconds
Battery: 19000 mAh @ 3.3 Volt
Screens shots of the LoRa calculation
LoRa radio for weather station on 14 dBm
LoRa radio for weather station on 14 dBm
Has this application piqued your interest? Do you have a wireless IoT idea? Do you plan an IoT device with embedded antennas? Do you have an IoT prototype and have a need to optimise the design or minimise the price? If you have answered YES to any one of these questions, then please do not hesitate to drop an email to harald.naumann (at) gsm-modem.de and to ask for an proposal or some engineering services to make your IoT idea a cost-effective reality.