[aprssig] LoRa iGates are inserting RSSI & SNR in comment

[Heikki Hannikainen]

Hi,

Just for wider awareness:

Some LoRa APRS iGates are inserting RSSI & SNR values in the comment text, 
creating duplicate packets.

Here's one example where each single packet is multiplied into three 
different packets, because it reaches three igates. One iGate doesn't 
modify the packet, the two others add different RSSI & SNR values.

https://aprs.fi/?c=raw&limit=&call=OK2ZAW-17

2024-05-28 21:54:33 EEST: OK2ZAW-17>APLG0,qAO,OK1FWG-10:=5016.90NL01625.35E&LoRa sun DiGi
2024-05-28 21:54:33 EEST: OK2ZAW-17>APLG0,qAS,OL7M-10:=5016.90NL01625.35E&LoRa sun DiGi DP_RSSI: -99 dBm DP_SNR: 9.75 dB
2024-05-28 21:54:33 EEST: OK2ZAW-17>APLG0,qAS,OK2ZAW-18:=5016.90NL01625.35E&LoRa sun DiGi DP_RSSI: -111 dBm DP_SNR: -15.25 dB

Naturally each different iGate injecting a unique RSSI value will create 
another duplicate. I'm now dropping these corrupted packets at aprs.fi.

There's some discussion on this here:

https://groups.io/g/APRS/topic/lora_aprs_igates_and/106326352

   - Hessu