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LoRa Gateway Antenna not picking up anything

Hello,
We have been trying to get our LoRa gateway to pick up packets from our end nodes. Previously, before we had transferred our gateway to a new location, it had been able to pickup packets from our end nodes but now we couldn't.

The above ground level of our gateway is 35 meters. We placed the end nodes in various locations (a few meters to several several kilometers) and are about 1 meter above ground level. but none have been picked up in the gateway's log files, not even corrupted packets.

We have been able to pin point the likely culprit is the gateway's antenna by taking it off and then tested to see if we could receive packets in a short range. We were able to receive the packets but now we are wondering what exactly is wrong with the antenna.

This is the specs of the antenna: https://cdn3.taoglas.com/datasheets/OMB.868.B05F21.pdf.
Are the specs inadequate for what we are trying to achieve? Could the antenna be damaged? I have read somewhere that if a transmitting end node is too close to the gateway's antenna, the antenna would get damaged. Is this true and if so how much should the minimal distance be?
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Hi,

What is your LoRaWAN regional parameters ? Could you please confirm that you are at 868 MHz ? Are you able to visually check your connectors to see that nothing is broken ? Also please check your cable continuity.

Do you have acces to a VNA to check antenna's frequency ?

Having devices close to the gateway can not damage the antenna, but can damage radio chips. Few meters away is a safety rule of thumb, even if you can get closer.

What is the device RSSI with device close to the gateway ?


As a reminder, the packet forwarder need to be set to your antenna gain in order to respect your local regulations.
Thanks for your reply Olivier.

We are not using LoRaWAN, just only LoRa. Our LoRa settings are 125KHz bandwidth, Spreading Factor 12 and the Coding Rate 4/5. We have configured our LoRa network to use the 865.20MHz frequency and we are able to confirm we are on this frequency by using a packet sniffer. Looking at the connectors, nothing seems to be broken. From what my colleague said, we cannot check the cable continuity because the connector is sealed.

Unfortunately we do not have access to a VNA.

The device's RSSI varies between -50dbm to -110dbm. Although sometimes whenever a packet is received, the next packet did not get picked up. We are the only users of this frequency in the area.

Our packet forwarder's antenna gain are set to respect our local regulations. Our gateway will only be receiving the packets. There is no two way communications.
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Have you confirmed that both device and gateway are set to use the same preambles and I/Q invert or not?