Suddenly RSSI and SNR decreased of nodes

Hello,

We have installed about 300 nodes, and 4 gateways in 3km of area, and running from 20 days.
All nodes data comes from 18 days. Suddenly from last 2 days, We are getting data of only 20-25 devices.
And also these 20-25 devices RSSI and SNR decreased by sharply, can say from +8 SNR to -10 SNR, in all 20-25 devices.
We also checked that Node and Gateway, Antenna, is connected properly, and doesn’t seems to have any issue,
and we doesn’t change any software or hardware side configuration in 20 days.

Please guide us what can be issue in this case?
Hs anybody face this type of issue?

Thank You

To help fill in the details, a few questions:

  • What area? The co-ordinates of the centre would be useful to see if anything may interact with the terrain. And also what the temperatures & weather is like - we’ve no idea where in the world you are.
  • Did it happen all at the same time?
  • Are the remaining devices heard by a mix of the gateways?
  • Are any of the remaining devices heard by more than one gateway?
  • When all the devices were operational, were any heard by two or more gateways?
  • Are any of the remaining devices in this all list and are they still heard by the same gateways?
  • What are the devices, gateways & antennas? (model numbers please)
  • How are they powered (exact model / order code of battery)
  • Is this on TTN or a paid for instance?
  • Have there been any announcements about a new radio service in the area - like a summer pop-up radio station?
  • Has anything happened around the environment of the gateways? (building work / scaffold etc)
  • Are the missing-in-action devices actually still there / transmitting? (ie, go and retrieve one)
1 Like

Have you had rain in the last 2-3 days?

Has there been a near miss lightning strike close to any of the gws….this can render near deaf, leaving either other distant gws to cover or the affected gw continues to pass messages but with severely reduced signal strength (rssi &/or sni)… have seen 30-65db reduction in rssi in the past….

1 Like
  1. Area: 28.2490° N, 77.8549° E( Khurja, India). In last 5 days temperature max is 31 degree Celsius. In start of 5-6 days there is rain, but from last 5-6 days no rain in this area.
  2. All happen at same time from after 26-8-2020 7:00 AM IST.
  3. no only nearby devices to gateway’s(about (200-400 meter) heard, no mix of the gateway.
  4. Yes some devices are heard by multiple gateways before this issue, they are in between of these gateway.
  5. Nearby devices to gateway heard by same gateway as before.
  6. Devices uses RAK3172 Module, and gateway is RAK7268, antenna is 5dBi RAKWireless RAKARG18 Antenna.
  7. Devices Are powered by a PANASONIC NCR18650GA 3500mAh (3c) LI-ION BATTERY (using a voltage LDO), also device battery is healthy 4180mAh nearby (on start -4185mAh) in all devices.
  8. TTN
  9. Hard to find, We started to searching about this.
  10. no changes or development like building near gateway.
  11. Yes they are working, we relocate 5 device near to gateway(doesn’t off or change any configuration just relocate), and they are working, but SNR is poor.

Did you weather proof the antenna connectors?

We use high end N-Type connectors, although they are stated to be weather sealed, over time they get water ingestion. This is due to the rapid temperature change when it rains. So we always seal with a self vulcanizing tape and then some insolation tape with two cable ties.

The self vulcanizing tape is not UV stabilized, that is why we add the insolation tape to protect from the sun.

2 Likes

I’m guessing it could be ADR setting gone wrong or the battery (measure the voltage). Most of the transceiver module can run down to 1.8V, but of course the power output drops and range reduces as a result.

This can be issue, Thanks for suggestion

If all the devices are the same, I’d look at the firmware - the code you wrote to run the device.

The only standout item in your answers is:

Having 300 nodes on TTN doesn’t reflect community use - is this a commercial setup?

Yes commercial setup

So you are consume the resources of TTN for your commercial endeavours as well as hoping for free support?

3 Likes

The circle represent a 20km radius, no public location published for any gateways.

So no community users are aware of a gateway available for use.

image

This is forum, and and helps each other, so if some want to be paid, then I think its not a right place. and I think everybody here is doing something commercial projects, testing Lorawan in real projects.

Gateway doesn’t have GPS so location is wrong in map.

Testing is half a dozen devices and a couple of gateways - it’s not 300 devices - and once more “I think” isn’t accurate - TTN is the community network primarily for community, maker, personal & learning use and yes, those starting out with their commercial activities.

But not 300 devices and no publicly published gateways - gateway coverage being the heart of TTN

So set them up properly - there are only 8 to do after all!

1 Like

Testing a dozen and testing 300 node, there is huge difference between them. Dozens are setup easily and tested, with no issue, but as network become dense, problem like this start over. So, 300 is also testing. Yes I will set gateway location properly,
But now issue is of RSSI and SNR decreases suddenly, and not able to find any clue, tried to change gateway & its Antenna to new one, some nodes, but it didn’t help.

Easily solved using the ‘Location’ tab on the GW console page, good community practice is make public so users know it exists and show approx. correct location - unless moved for temp test deployments, rtb for repairs/updates etc. or if security a potential issue for housed or remote GW then reality is dither actual location by say 25-250m.

2 Likes

From a hobbyist.

Post the JSON part with the gateway information in it. Post a few so we can form a good understanding of how the RF environment looks like. And we can see where you are noticing the degradation in the RF.

Will also bee good to know the rough location of the nodes and gateways you are using for the sample data.

Please indicate which one is the original getaways and the replace ones.

If you say you have made no software changes, it needs to be the hardware or environment.

When you took the gateway down, have you opened the gateway and antenna and inspect for water?

If you can afford 300 devices to test with, why can’t you run your own stack?

And testing at that volume is not something the community is very keen on because if you are not confident in your systems and need to test that many nodes, what impact might that have on TTN?

1 Like

Sorry @descartes, I read your answers in many other questions, and I feel , that you try to change the main objective of question. My issue may be faced by other, in future may be using TTN, or their own stack. Issue is of RSSI and SNR, not of stack or TTN to use, please be specific to question.