B-WL5M-SUBG1 LoRa communication range issue

[VR_Antoine]

Hello everybody,

For a proof of concept, I attempted to validate the LoRa modulation by having two B-WL5M-SUBG1 boards exchange ping-pong messages. However, I couldn't manage to exchange data with these boards at a distance greater than 230m in an open field. I expected at least 1km of communication distance.

My radio configuration is the following:
Tx output power: 14dB
RF frequency: 868.0 MHz
Bandwidth: 125kHz
Spread factor: SF7
Coding rate: 4/5
I used the antennas coming with the development boards

Few questions:
- I have connected the B-WL5M-SUBG1 to a vector analyzer and measured a VSWR of 2.339 for the 868.00 MHz frequency. Is it expected to change the C19, C20, and L1 components to better adapt the board for my frequency to reach the expected communication range?
- Are the provided antennas with the development board able to reach a communication range greater than 250m?
- I have found the AN5528 evoquing range greater than 1km for S2-LP in 868MHz. Should I expect similar results with WL5 MCU?

[VR_Antoine · Accepted solution]

After new tests, I finally succeeded in reaching the expected communication range with the B-WL5M-SUBG1 board.
My main issue is that I was using a plastic pocket to protect the board from rain. However, the pocket I used appears to be ESD-proof and effectively mitigates a lot of my radio signal.

For those interested, I managed to reach about 900m without the plastic pocket, using the same radio configuration as in the initial post. Also, one of my boards was lying on the ground, so better results should be expected with both antennas placed 1m above the ground.

Yet, if someone can answer me, whether a 50-ohm impedance matching on these boards is expected to achieve the best results. I would be glad to know the answer.