Can somebody explain what are the benefits of using the Lora E5 HF over the STM32WLE5JC module itself. The STM32 part has a Sub-GHz radio system peripheral in the module already so doesn’t really need an additional SX126X…
I can see that if you use it “as is”, there is the benefit of not having to write the code for the module but there is also instructions how to erase the firmware it’s shipped with an reprogram with STM32 software.
Many thanks.
Quote from
“It contains ST system-level package chip STM32WLE5JC, and this STM32WL module is the first SoC integrated with the combo of LoRa RF and MCU chip. This module is also embedded with ARM Cortex M4 ultra-low-power MCU and LoRa SX126X and therefore supports (G)FSK mode and LoRa.”
So wie ich das sehe ist da gar kein Semptech SX chip drin sondern alles CPU / SDR / HF front end von STM mit den Schwierigkeiten von mixed signal chips.
Ich habe außerdem den Verdacht, daß die Performance deshalb nicht so toll ist. Die Messkurven im datasheet von LORA E5 HF sagen Empfindlichkeit bei SF12 -136 dBm.
Demgegenüber behaupted das data sheet vom RAK11720 eine Empfindlichkeit von -148dBm.
Wenn ich da nichts missverstanden habe wären das 12 dB Abstand, das würde die 4 fache Reichweite im Freiraum zugunsten RAK11720 über Seeed ergeben, - oder eben den kleineren Spreizfaktor mit höherer Bitrate.
it looks to me, that in seeed lora e5 there is no discrete SEMTECH chip but some RF on a mixed signal CPU by STM, - with the problems of mixed signal noise reducing RF performance.
data sheet Lora E5 says -136dbm RX performace, but RAK11720 says -148dbm. If that is true then RAK reaches 4 times as far ( 26db= 2doubledistance free field). Is there an independent benchmark somewhere ?
Maybe it is exactly as you said, or maybe the module manufacturers specified the receive sensitivity in different modes of operation of the Lora receiver
hello and thanks,
yes I agree. Meanwhile I found the SX1262 data sheet as well which is contained in RAK discretely as a chip product and in Seeed integrated as on mixed signal silicon.
As you found out Semtech only archieves -148dbm when operating SF12 using 12.4KHz which is not relevant for most apps.
At SF12 /125kHz Semtech states -137db which is in line with Seeeds measurements. RAK cannot have more using SX1262, so I now think there is no big difference. I was wrong.
Starting from there, Seeed is the better solution for us, because RAK does not do LBT in EU868 mode. Seeed seems to do that independent of the US/CN/EU mode. Unfortunately details are not given wether that matches ETSI regulation for more than 1% air time duty cycle. … need to futher investigate.
