Indoor range of HTCC-AB02

Hello,

recently i bought some HTCC-AB02 CubeCell boards, to test the indoor range of the LoRa transceiver. Before i tested the indoor range with some other RF transceiver with a receiver sensitivity of around -113 dBm, the SX126x LoRa transceiver should have about -130…-140 dBm. So the range should be much greater than before, but it isn’t.

With a range of some meters between two HTCC-AB02 boards the RSSI is -50 and the SNR is 3 or 4. With some obstacles and around 70 meters between these boards (pingpong example from git) the RSSI shows -110 and SNR -14 or less. Then 2 meters more in range the communication isn’t possible anymore.

Why is the RSSI so bad in short distance with no obstacles and why doesn’t the RSSI goes down to -130…-140?

LoRa settings:

  • 868 MHz
  • 14 dBm
  • SF 12
  • 125 kHz
  • coding rate 4/5
  • preamble length 8

This article shows LoRa communications over a 12-floor building https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8273458

Try increasing TX-power to 22dBm? I tested HTCC-AB01 with the LoRa32V2 on the other end and I got about 2km range with just the basic, crappy antennas and through several buildings and some forest.

Besides which, if you wanted even better results, you should buy 433MHz - parts; the higher the frequency, the less easily the signal penetrates through obstacles.

I’m in Europe so +14 dBm is the maximum allowed transmit power on 868 MHz. Did you test the range in buildings over several floors or only the horizontal communication?

I know that 433 MHz would perform better then 868 MHz in range. But there are more devices that work on 433 MHz and there are no restrictions.

Only horizontal. Haven’t had the need to test vertically.