ERROR: Packet REJECTED, unsupported RF power for TX - 17

LPWAN Developer Gateways / Concentrators RAK2245 / RAK2243
1

Issue: Downlink “txpk”-type packets not delivered

Setup: RAK2245 PiHat on a Pi-3B+ running Buster, ttn-gateway

Server:Pi-3B+

Details:
I’ve been monitoring traffic through my RAK2245 gateway while trying to get the GPS working. I noticed the following sequence. Seems like an error in the lora_pkt_fwd code in which the transmit power setting for "powe" to a value of 17 isn’t accepted. I haven’t got my remote sensor node (a SAMD21) connected via USB right now so can’t see if it got a packet or not, but it seems like it wouldn’t have. The error is reported in about line 2591 of packet_forwarder/lora_pkt_fwd/src/lora_pkt_fwd.c, but I’m not experienced enough to know if that’s a problem in the c code or in the lut definitions in which there are no lut entries with a power of 17.

JSON up: {“stat”:{“time”:“2020-03-19 09:31:11 GMT”,“rxnb”:0,“rxok”:0,“rxfw”:0,“ackr”:0.0,“dwnb”:0,“txnb”:0}}
INFO: [down] PULL_ACK received in 90 ms

INFO: Received pkt from mote: 2602141D (fcnt=47)
payload size = 52
payload = QB0UAiaALwABuH7GIq1VqX/StG9oeMA83nVFS+b/VIQQdhFF+A==

JSON up: {“rxpk”:[{“tmst”:288042532,“chan”:7,“rfch”:1,“freq”:905.300000,“stat”:1,“modu”:“LORA”,“datr”:“SF7BW125”,“codr”:“4/5”,“lsnr”:9.0,“rssi”:-53,“size”:37,“data”:“QB0UAiaALwABuH7GIq1VqX/StG9oeMA83nVFS+b/VIQQdhFF+A==”}]}
INFO: [down] PULL_RESP received - token[0:19] :slight_smile:

JSON down: {“txpk”:{“imme”:false,“tmst”:289042532,“freq”:927.5,“rfch”:0,“powe”:17,“modu”:“LORA”,“datr”:“SF7BW500”,“codr”:“4/5”,“ipol”:true,“size”:22,“ncrc”:true,“data”:“YB0UAiaKMAADQAIAcQM6AP8Bu7eejw==”}}
ERROR: Packet REJECTED, unsupported RF power for TX - 17
INFO: [down] PULL_ACK received in 91 ms
INFO: [down] PULL_ACK received in 99 ms

2

Please download https://github.com/RAKWireless/rak_common_for_gateway/blob/master/lora/rak2245/lora_pkt_fwd.c and replace /opt/ttn-gateway/packet_forwarder/lora_pkt_fwd/src/lora_pkt_fwd.c.

Then execute the following command to recompile lora_pkt_fwd:
1.sudo systemctl stop ttn-gateway
2.cd /opt/ttn-gateway/packet_forwarder/lora_pkt_fwd
3.sudo make clean; sudo make
4.Restart the gateway

3

@ ZhuQI,

Thanks, but I had just cloned that repository yesterday to do the new install, so I already had the lora_pkt_fwd.c code that was updated 7 days ago.

I did as you suggested, anyway, and I did a diff of the file I downloaded yesterday and the file I downloaded with your instructions above, and the files are the same.

But I did the make clean and make and ran ./start.sh and continued to get WARNING: [gps] could not get GPS time from GPS.

So it’s not out-of-date lora_pkt_fwd.c code that’s the problem.

David

4

@ZhuQI,

My apologies: you’re right.

I had done a fresh clone and install when I got those packet rejected error messages, but I’ve just gone back and recompiled and retested, and I see that the code now adjusts the power setting to 16 if 17 is requested. I have no idea where I invoked the old code from, but the new code fixes the problem.

Thanks for your help!

David

5

I am very happy to solve your problem. :smile: :smile: :smile:

6

Sorry for the late response, this issue was identified, documented and fixed here: