LR1110 receive issue

[AlanGWard]

Hi,
I have a setup that uses a LR1110 (firmware 4.1) on the device end and an SX1302 on the base station end.
I'm using Radiolib on the device and the Semtech message forwarder on the gateway.
The device is a tracker and sends a (24 byte) fix once per minute. The gateway then responds with a short (5 byte) ACK.
If the device doesn't receive a response it tries again up to 3 times
This all works fine. It's a mechanism I have been using for several years, but with a SX1262 on the device end.

However, occasionally I need to send configuration update data to the device from the gateway. This message is 29 bytes.
It takes a number of attempts (maybe 10) before the message gets through.

Is there a compatibility problem between the LR1110 and the SX1302 that you are aware of?

Thanks
Alan

[jgromes]

I'm not aware of anything major in the LR1110 that is significantly different from SX126x - definitely not something that could be impacting this. I guess more information is needed. Waht is the behavior of the receiver when the message fails to "get through"? Does it simply not not receive the packet, or is there some error?

[AlanGWard]

Hi, Thanks for your quick response.I am using the interrupt driven receive, so basically I see nothing.Maybe I should switch temporarily to the blocking receive and see if I can spot any error occurring .I have the device connected through the Nordic Power Profiler. Normally, I see a flat line followed by a peak when the receive occurs. My code at that point is trivial as I just reset a timer. When this ‘failure’ occurs I see nothing other than a flat line which I guess is the current taken by the radio in receive mode. So I assume it is just not receiving the packet. Thanks againAlan Ward07508 935833On 15 Apr 2025, at 16:55, Jan Gromeš ***@***.***> wrote: I'm not aware of anything major in the LR1110 that is significantly different from SX126x - definitely not something that could be impacting this. I guess more information is needed. Waht is the behavior of the receiver when the message fails to "get through"? Does it simply not not receive the packet, or is there some error? —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you authored the thread.Message ID: ***@***.***>

[jgromes]

Maybe I should switch temporarily to the blocking receive and see if I can spot any error occurring

If you don't see any output then that probably means the radio is not sending the DIO signal, so blocking receive will not help since it is waiting for the same DIO signal.

In this case, I will need to know what is the configuration of the packet sent from the gateway? Not just the basic stuff like frequency, SF, BW and CR but also things like CRC configuration, whitening, explicit/implicit header mode etc.

[AlanGWard]

Hi, I don’t know where to get that information . I am using the Semtech packet forwarder and that uses standard LoRaWan settings. All I have changed is Public to Private.
Clearly it is the same settings for the 5-byte messages that work and the 29-byte messages that eventually work.
I am currently setting up another (modified) base station to see if the messages are actually being transmitted.

Thanks Alan

[jgromes]

using the Semtech packet forwarder and that uses standard LoRaWan settings

In that case all the less-known settings I listed above should be configured to their default values and should work fine with LR1110. I haven't seen behavior like this before, sorry. For what it's worth, I've had LR1110 running as a LoRaWAN node with the gateway being SX1302 without issues. If I was debuggin this, I would try to send the 29-byte message from the SX1262. If the issue persists, it could be some problem in the LR1110 configuration. If it goes away, my suspicion would be some issue in the SX1302 that for whatever reason does not manifest with SX126x.