LoRaWAN 915Mhz in the US
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After not being able to get the LoPy/LoRaWAN to work with my Multitech Conduit gateway configured for 915Mhz (USA), I grabbed the source to understand why (Other LoRaWAN devices worked out of the box).
I determined that the add_channel and remove_channel methods do not have any effect for LoPy's loaded with 915Mhz configured firmware. Channel configuration is necessary if you have a gateway that can only listen on 8 channels (most gateways, including the Multitech are limited to 8 channels of the 915Mhz band). This meant that I had a 1 in 8 chance of joining or receiving messages as the LoPy was trying to use all 64 channels instead of the 8 the gateway could receive.
I added basic functionality to the firmware to make remove_channel() functional on 915Mhz configured LoPys. This is enough to make the LoPy work 100% reliably with my Multitech Conduit/Things Network gateway since I can prevent the LoPy from using channels that the gateway isn't listening on.
Here is sample code that works for joining TTN and sending 20 messages:
from network import LoRa import socket import time lora = LoRa(mode=LoRa.LORAWAN, public=True, adr=False) #Setting up channels for sub-band 2 for TTN for index in range(0, 8): lora.remove_channel(index) for index in range(16, 65): lora.remove_channel(index) for index in range(66, 72): lora.remove_channel(index) auth = (bytes([... ]), bytes([... ])) print("joining...") lora.join(activation=LoRa.OTAA, auth=auth, timeout=0) x=0 # wait until the module has joined the network while (not lora.has_joined() and x<10): time.sleep(2.5) print('Not yet joined...') x=x+1 print(lora.has_joined()) if (lora.has_joined()): # create a LoRa socket s = socket.socket(socket.AF_LORA, socket.SOCK_RAW) lora.remove_channel(65); #drop the 500khz channel for index in range(0, 20): s.send("test1234567");After some headaches figuring out GitHub and Pull requests, I submitted the changes to be included in a future firmware release. I should add that Fred and Daniel with Pycom have been very helpful--thanks to both of them.
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Just for easy reference, here is a table of frequencies and data rates that are the default in 915Mhz:
channel 0: 902300000 hz min_dr 0 max_dr 3 channel 1: 902500000 hz min_dr 0 max_dr 3 channel 2: 902700000 hz min_dr 0 max_dr 3 channel 3: 902900000 hz min_dr 0 max_dr 3 channel 4: 903100000 hz min_dr 0 max_dr 3 channel 5: 903300000 hz min_dr 0 max_dr 3 channel 6: 903500000 hz min_dr 0 max_dr 3 channel 7: 903700000 hz min_dr 0 max_dr 3 channel 8: 903900000 hz min_dr 0 max_dr 3 channel 9: 904100000 hz min_dr 0 max_dr 3 channel 10: 904300000 hz min_dr 0 max_dr 3 channel 11: 904500000 hz min_dr 0 max_dr 3 channel 12: 904700000 hz min_dr 0 max_dr 3 channel 13: 904900000 hz min_dr 0 max_dr 3 channel 14: 905100000 hz min_dr 0 max_dr 3 channel 15: 905300000 hz min_dr 0 max_dr 3 channel 16: 905500000 hz min_dr 0 max_dr 3 channel 17: 905700000 hz min_dr 0 max_dr 3 channel 18: 905900000 hz min_dr 0 max_dr 3 channel 19: 906100000 hz min_dr 0 max_dr 3 channel 20: 906300000 hz min_dr 0 max_dr 3 channel 21: 906500000 hz min_dr 0 max_dr 3 channel 22: 906700000 hz min_dr 0 max_dr 3 channel 23: 906900000 hz min_dr 0 max_dr 3 channel 24: 907100000 hz min_dr 0 max_dr 3 channel 25: 907300000 hz min_dr 0 max_dr 3 channel 26: 907500000 hz min_dr 0 max_dr 3 channel 27: 907700000 hz min_dr 0 max_dr 3 channel 28: 907900000 hz min_dr 0 max_dr 3 channel 29: 908100000 hz min_dr 0 max_dr 3 channel 30: 908300000 hz min_dr 0 max_dr 3 channel 31: 908500000 hz min_dr 0 max_dr 3 channel 32: 908700000 hz min_dr 0 max_dr 3 channel 33: 908900000 hz min_dr 0 max_dr 3 channel 34: 909100000 hz min_dr 0 max_dr 3 channel 35: 909300000 hz min_dr 0 max_dr 3 channel 36: 909500000 hz min_dr 0 max_dr 3 channel 37: 909700000 hz min_dr 0 max_dr 3 channel 38: 909900000 hz min_dr 0 max_dr 3 channel 39: 910100000 hz min_dr 0 max_dr 3 channel 40: 910300000 hz min_dr 0 max_dr 3 channel 41: 910500000 hz min_dr 0 max_dr 3 channel 42: 910700000 hz min_dr 0 max_dr 3 channel 43: 910900000 hz min_dr 0 max_dr 3 channel 44: 911100000 hz min_dr 0 max_dr 3 channel 45: 911300000 hz min_dr 0 max_dr 3 channel 46: 911500000 hz min_dr 0 max_dr 3 channel 47: 911700000 hz min_dr 0 max_dr 3 channel 48: 911900000 hz min_dr 0 max_dr 3 channel 49: 912100000 hz min_dr 0 max_dr 3 channel 50: 912300000 hz min_dr 0 max_dr 3 channel 51: 912500000 hz min_dr 0 max_dr 3 channel 52: 912700000 hz min_dr 0 max_dr 3 channel 53: 912900000 hz min_dr 0 max_dr 3 channel 54: 913100000 hz min_dr 0 max_dr 3 channel 55: 913300000 hz min_dr 0 max_dr 3 channel 56: 913500000 hz min_dr 0 max_dr 3 channel 57: 913700000 hz min_dr 0 max_dr 3 channel 58: 913900000 hz min_dr 0 max_dr 3 channel 59: 914100000 hz min_dr 0 max_dr 3 channel 60: 914300000 hz min_dr 0 max_dr 3 channel 61: 914500000 hz min_dr 0 max_dr 3 channel 62: 914700000 hz min_dr 0 max_dr 3 channel 63: 914900000 hz min_dr 0 max_dr 3 channel 64: 903000000 hz min_dr 4 max_dr 4 channel 65: 904600000 hz min_dr 4 max_dr 4 channel 66: 906200000 hz min_dr 4 max_dr 4 channel 67: 907800000 hz min_dr 4 max_dr 4 channel 68: 909400000 hz min_dr 4 max_dr 4 channel 69: 911000000 hz min_dr 4 max_dr 4 channel 70: 912600000 hz min_dr 4 max_dr 4 channel 71: 914200000 hz min_dr 4 max_dr 4
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I've now submitted changes to make add_channel functional for 915Mhz, too. They should be visible in the pull request if you want to roll your own firmware.
Here is some sample code to for using add_channel to configure a sub-band:
from network import LoRa import socket import time def select_subband(lora, subband): if (type(subband) is int): if ((subband<1) or (subband>8)): raise ValueError("subband out of range (1-8)") else: raise TypeError("subband must be 1-8") for channel in range(0, 72): lora.remove_channel(channel) for channel in range((subband-1)*8, ((subband-1)*8)+8): lora.add_channel(channel, frequency=902300000+channel*200000, dr_min=0, dr_max=3) lora = LoRa(mode=LoRa.LORAWAN, public=True, adr=False) select_subband(lora, 2)