Indoor range of HTCC-AB02

#1

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

#2

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.

#3

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.

#4

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

#5

any update about this?
I came across a similar problem

#6

Linkbudget is about 151 dBm (SF12)!
Now you can calculate all the walls and other things like defraction!

One normal building would be not a problem!

E_T

#7

Sorry i have no updates for that problem.

Like @ernst.schulz says the link budget should be 151 dBm at SF 12, but my RSSI doesn’t go down to that limit. My maximum limit was down to -113 dBm, missing the rest down to -151 dBm…