Hello. I have a Dragino LPS8 gateway and some temperature and humidity Dragino LHT65 sensor and I have encountered a really annoying problem that prevents me from getting readings from TTN outside a limited distance range.
I’m installing this system on my workplace that is a manufacturing plant, we want to place the sensors inside the production area but we encountered a problem with this.
The Gateway and Sensor have to be forcefully in a distance more or less between 10 to 30m apart. If the sensor gets more than that apart from the gateway, we stop getting readings from TTN without touching a single configuration. The gateway log displays data is being sent but not uploaded, also the sensor blinks blue when I request a manual downlink indicating that a message is being sent, we also sometimes get an accepted join request from sensor on TTN but we never get readings outside that distance range.
30m is a really short distance considering that the LoRaWAN technology promises to work with 15km distance. It is really an impossibility for us to have the gateway that close since we plan to place various sensors across a space of around 200m indoors and we also don’t have available ethernet nodes to connect inside the production area.
We are running the gateway on a private network with admin permissions so firewalls are not the problem. What could be the problem? Are there any solutions?
Look at the wiring, what you’ve used, give us details on the antenna, placement, lumps of metal, electrical interference, moving bags of water standing next to the antenna having a fag break.
PS, there is no such thing as “standard” range. My record is currently 5cm (gateway + device on my desk, appropriate antenna arrangements to prevent overload) and 118km (gateway at home with moderately OK mag mount antenna, device at 31,000m with a bit of bent wire for the antenna).
There are a few problems you can have in an industriell enviroment when using LoRaWAN.
One problem is the RF-propagation that is disturbed by machines and metallic construction parts or walls.
The other problem can be EMC. Motor drives, welding machines, electronic systems emitt RF-noise that can disturb the used frequencies.
The LPS8 gateway and it’s power supply are not intended to be used in an industriell enviroment. You need additional filters and overvoltage-protectors.
We need to know more about your environment and how you installed gateway and antenna to give you some hints.
Hi. The gateway is placed on an office inside the plant, with the antenna being upright. And yes we have AHU’s, motors, pumps, forklifts, data centers, you name it… near the gateway and the sensors.
What can it be recommended to do in these cases? Are there any possible solutions other than getting another more powerful gateway?
No such thing…all GW’s are essentially same core technology just built to meet different environmental and operational standards whilst working to the (local) legal limits on RF etc.
Can I simply attach a bigger antenna into the gateway?
Doesn’t help (search forum) as bigger(as in higher gain) ant means having to dial down gw Tx power to keep within limits above, and brings with it additional complications such as notching & often unwanted directionality…and in industrial environments with more metal around can often end up firing stronger reflections etc.
LoRa/LoRaWAN can be made to work well and certainly better than many (most?) other technologies in really challenging environments such a the bowels of ocean liners and their boiler/engine rooms and deep in nuclear installations… it all about how tuned and how configured…and not doing sillies like adding rp-sma antennas to standard sma’s, female to female, etc (Yes, I got the TShirt!). Tell us more about set up config environment (picture work well…) etc and we may be able to help/advise…also grab a soft RF receiver/spectrum analyser and monitor the local RF environment for a while to see what you may be up against…
Check that both gateway and node antennas are actually connected to the respective radios.
Also check that all the hardware is specifically for the frequency band it’s being used on, and not another which might make the tuning networks less than optimal.
Node radios also have some RF path selection, but hopefully the vendor firmware would get that right.
Thanks for your insight. I currently dont have access to a RF spectrum analyzer and it is relevant to say that the system works on a domestic environment perfectly but not in the industrial environment that we bought this system for (without touching configurations). The devices are configured correctly as per the user manual and they work perfectly fine. The only problem is the limited distance the sensors need to be in order to work inside the plant.
I’ve tried placing the gateway in various places and with different antenna placements and we have the same results. Do we have a faulty gateway? What hopes do I have of this working?
What sort of distances were you achieving then? Similar short range only or did you test in the true far field? In moving have e.g. antennas been swapped or failed to be retightened/not properly fitted etc.
What rssi & snr values are you seeing at the gateway (as reported via ttn console)?
Where/how are nodes mounted…hidden/underneath big lumps of metal can screen and depending on ant type may serve to ‘de-tune’ ideal operating frequencies, which then becomes a problem similar to running gw and or node on wrong or mis-matched frequencies, imparing signal leves etc. need lots of details and analysis to really help without actually being on site…
While these are excellent sensors, the internal antenna of them is close to the battery impacting the antenna performance. The Dragino LNS50 or LTC2 series would be better devices for your application.
I connected the gateway and placed the sensor in a distance range that most of the time works (around 5m) to test what you say. rss values vary from -90 to -100 and snr form 7.5 to 9. If I test it from a larger distance I cant get the values since it stops reading.
I didn’t test it on a true far field just a couple of meters since thats where i’m having problems. The nodes are just placed on a desk near the gateway for testing. If I handhold the sensor and move away from the office it stops getting readings. Both the gateway and nodes are set to US915 F2 band used by TTN. Since I’m in a manufacturing plant there are a lot of machines such as AHUs and industrial air compressors nearby.
Then your system is clearly badly set up or defective! Sorry. 5m is actually too close and is at the inner limit of recommended safe and reliable/consistent operating distance between Node & GW that can reasonably be used - we woudl normally suggest min 5-10m ideally with a wall or other absorber in between. Otherwise you are ‘shouting in each others ears’ At 5m in normal modes of operation and with antenna properly connected, matched and aligned you would likley be seeing RSSI values around -35 to -50db with SNR 7->10. Fact you are only seeing -90 to -100 is a problem. Have you ever run GW or node without antenna attached? (If so Tx energy reflects back into RF front end imparing long term operation and in some cases knocking reception out). Also if operated close to a lightning strike I have see front ends degrade anywhere from -20 to -50db below normal operation, but still ‘function’.
I would recommend take back home. set GW on a window high in your building (if weather allows even place outside for a short time!) and take node 100, 250, 500 & 1000m approx away from GW with clear line of site and see what you get…then report back
This are the values I get when my LIG16 gateway is working on a dummy load and the node has its"normal" antennas. Looks like there is something broken.
Exactly, one of the antennas isn’t actually connected to the radio chip at one end or the other.
If that’s a broken antenna cable, broken antenna connector, broken circuit board, or software not setting an RF path correctly would be the question that needs answering.
At 5m in normal modes of operation and with antenna properly connected, matched and aligned you would likley be seeing RSSI values around -35 to -50db with SNR 7->10. Fact you are only seeing -90 to -100 is a problem. Have you ever run GW or node without antenna attached? (If so Tx energy reflects back into RF front end imparing long term operation and in some cases knocking reception out). Also if operated close to a lightning strike I have see front ends degrade anywhere from -20 to -50db below normal operation, but still ‘function’.