Setup for Range Test
The receiver was placed in the middle of a room, 1 meter above the floor. The room was in the third floor of a building, approximately 8 meters above ground. The windows were closed.
The humidity outside was 48%, temperature was 9.5 °C.
The path between sender and receiver was not completely unobstructed. There were parts of a building in between.
The humidity outside was 48%, temperature was 9.5 °C.
The path between sender and receiver was not completely unobstructed. There were parts of a building in between.
The receiver
The receiver was a Canique MK2 with an integrated RFM69HW 433MHz radio module mounted on a breadboard. Breadboards are not ideal for such tests.
The MK2 was connected to the 5V rail of a Raspberry Pi 3 which was connected to an official Raspberry Pi power supply.
A 0.01 uF capacitor was used on the input of the MK2 - it might well be that the capacitor is not needed at all.
The antenna of the Canique MK2 was a straight vertical wire antenna of 17.3cm length.
The MK2 was connected to the 5V rail of a Raspberry Pi 3 which was connected to an official Raspberry Pi power supply.
A 0.01 uF capacitor was used on the input of the MK2 - it might well be that the capacitor is not needed at all.
The antenna of the Canique MK2 was a straight vertical wire antenna of 17.3cm length.
The sender
The sender was a Canique MK2 with an integrated RFM69HW 433MHz radio module. It was powered by a single Eneloop battery via a 3.3V Canique Boost.
The battery had a voltage of 1.33V at that time.
The antenna of the Canique MK2 was a straight vertical wire antenna of 17.3cm length.
The battery had a voltage of 1.33V at that time.
The antenna of the Canique MK2 was a straight vertical wire antenna of 17.3cm length.
The software
- Bitrate: 19.2 kbps
- AES: off (custom Chacha20-Poly1305 Encryption)
- CRC: off
- Payload length: 14-25 bytes (including sender byte, receiver byte and control byte)
- Transmission every 30 seconds
Results and Conclusion
- 1km range @ RSSI -100
- no transmission errors up to RSSI -95
- Very similar test with receiving MK2 connected to Raspberry Pi Zero (with EDIMAX EW-7811UN) showed poor result of 250 meters. Reason: Power supply or some data line has high ripple voltage.
- Conclusion: Make sure every cable connected to your MK2 has a clean voltage and does not oscillate.