LoRa Serial Kit Multipoint

Wireless & IoT LoRa (Long Range)
1

I must be dense because I cannot figure out how to get my new LoRa Serial kit to work in multipoint mode.

I have switched both units to AT-OperatingMode=0. I have set the same AT-Bandwidth on both. I have set AT-Server=1 on one and AT-Server=0 on the other.

I then ran ATT on both and saw:

Server training parameters
  Training netID: 192
  Training key: 537061726B46756E547261696E696E67
Server radio protocol parameters
  netID: 192
  Encryption key: 37782141A665734E4475672AE6308308
OK
Client C208853D5730305020312E50212A09FF Trained

and

Link trained from D9EFD0575730305020312E50221E09FF

I exited command mode on the server and it just shows all 4 RSSI lights lit.

The “client” shows no RSSI lights lit and I don’t seem to be able to send information between them with the serial console.

I tried several reboots.

I must be missing something, but not sure what.

Server ATR:

AT-AirSpeed=0
AT-AutoTune=0
AT-Bandwidth=10.40
AT-ClientFindPartnerRetryInterval=3
AT-CodingRate=8
AT-DataScrambling=0
AT-EnableCRC16=1
AT-EncryptData=1
AT-EncryptionKey=37782141A665734E4475672AE6308308
AT-FramesToYield=3
AT-FrequencyHop=1
AT-FrequencyMax=928.000
AT-FrequencyMin=902.000
AT-HeartBeatTimeout=5000
AT-MaxDwellTime=400
AT-MaxResends=0
AT-NetID=192
AT-NumberOfChannels=50
AT-OperatingMode=0
AT-OverHeadtime=10
AT-PreambleLength=8
AT-SelectLedUse=4
AT-Server=1
AT-SpreadFactor=9
AT-SyncWord=18
AT-TrainingKey=537061726B46756E547261696E696E67
AT-TrainingTimeout=1
AT-TxPower=30
AT-TxToRxUsec=657
AT-VerifyRxNetID=1

Client ATR:

AT-AirSpeed=0
AT-AutoTune=0
AT-Bandwidth=10.40
AT-ClientFindPartnerRetryInterval=3
AT-CodingRate=8
AT-DataScrambling=0
AT-EnableCRC16=1
AT-EncryptData=1
AT-EncryptionKey=37782141A665734E4475672AE6308308
AT-FramesToYield=3
AT-FrequencyHop=1
AT-FrequencyMax=928.000
AT-FrequencyMin=902.000
AT-HeartBeatTimeout=5000
AT-MaxDwellTime=400
AT-MaxResends=0
AT-NetID=192
AT-NumberOfChannels=50
AT-OperatingMode=0
AT-OverHeadtime=10
AT-PreambleLength=8
AT-SelectLedUse=4
AT-Server=0
AT-SpreadFactor=9
AT-SyncWord=18
AT-TrainingKey=537061726B46756E547261696E696E67
AT-TrainingTimeout=1
AT-TxPower=30
AT-TxToRxUsec=657
AT-VerifyRxNetID=1
2

I just saw the note in the docs about using the airspeed parameter instead of setting the bandwidth.

In P2P mode, I set AT-AIRSPEED=400, which I think is the lowest setting.

It set the bandwidth to 125.0. Is this the recommended setting for maximum range?

I also note that ATR always shows AT-AirSpeed=0

3

FYI, the AirSpeed will usually display as 0. AirSpeed isn’t a stored setting; when we set the AirSpeed, five other parameters are calculated to get us the AirSpeed we request, and these five parameters are then set. If you reset the modem and query AirSpeed, it will report as 0. Presuming you saved your settings to NVM (via ATW), the other parameters are stored and you should get the request AirSpeed.

I asked about this in the github for the source code a while back, and sparky responded by helpfully clarifying the documentation. https://github.com/sparkfun/SparkFun_Lo … issues/585

Go to this link in the documentation and scroll down a bit: https://docs.sparkfun.com/SparkFun_LoRa … o-commands

So if you’re like me and want to confirm I configured my modem properly and things “took”, it’s necessary to check the other 5 parameters that determine the effective AirSpeed.