LoPy4 LoRa Data Corruption

ssmith

I'm trying to get raw lora data transmission going on the LoPy4's. I've been running the original LoPy's for a year with no issues but the LoPy4's seem to get scrambled data. I created a small test program to verify. Any ideas what could cause this? I'm running the same code on 2 units.

import socket
import machine
import time

# initialize LoRa in LORA mode
# more params can also be given, like frequency, tx power and spreading factor
lora = LoRa(mode=LoRa.LORA)
lora.init(mode=LoRa.LORA, frequency=918000000, power_mode=LoRa.ALWAYS_ON, tx_power=20, bandwidth=LoRa.BW_125KHZ, sf=9,
              preamble=8, coding_rate=LoRa.CODING_4_8, tx_iq=False, rx_iq=False)
# create a raw LoRa socket
s = socket.socket(socket.AF_LORA, socket.SOCK_RAW)
# send some data
s.setblocking(True)
s.send('Hello From COM7')

while True:

    # get any data received...
    s.setblocking(False)
    data = s.recv(64)
    if data:
      print(data)
      time.sleep(0.5)
      s.setblocking(True)
      s.send('Hello From COM7')

    # wait a random amount of time
  #  time.sleep(1)

Here's the console output.

b'Hello From \xc7OM7'
b'Hello Erom \xc7OM7'
b'Hello From \xc5OM7'
b'Hello From \xc5OM7'
b'Hello From\x10\xc6OM7'
b'Hello From COM7'

seb

Hi,

Are both LoPy4's running on the latest firmware? We released a new update yesterday. Can you try updating both and let me know if the issue persists?

ssmith

Yes, both running 1.15. I also see it on ones running 1.13. If I run a lopy4 and a lopy I don't get any data through.

ssmith

This appears to be a receiver saturation issue. At what point does the LoRa receiver saturate? my rssi is at -25 on both devices. If I change the sf to 7 then I don't get errors.