Author Topic: RFM95: Troubleshooting Bad Data in with no CRC Error  (Read 104 times)

jamesod

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RFM95: Troubleshooting Bad Data in with no CRC Error
« on: May 15, 2019, 06:43:41 PM »
I have set up a few nodes communicating with a gateway using the RFM95 at 915MHz.
Everything seems to work fine, but occasionally I get bad packets in. I record the data being sent at the node, and the data received by the gateway. It doesn't match. The first byte is always ok, but after that it looks like garbage. I do not get any CRC errors during this transmission.
Radio settings are:  Bandwidth 31.25KHz, coding rate 4/8, implicit header off, spreading factor 512CPS, and Payload CRC on.
I check the interrupt flags after a transmission is received and the CRC flag is not ever set. The RSSI seems fine at -76.

I am a bit of a newbie at this, but I thought the CRC flag should be hit if the data is wrong. I have a routine that tells the node to resend data if the CRC flag is detected, but it never is. 
Any recommendations on what to troubleshoot next?