Help with new node/new gateway setup


(Cabsandy) #1

I have been lurking for a while and now need to ask a few questions-some may have been answered but I may need conformation and some help please. So apologies if they seem a bit noob!

My set up:

LoraWAN gateway on a RP3 B+ with a dual Uptronics board mounted running the dual packet forwarder https://github.com/bokse001/dual_chan_pkt_fwd

LoraWAN node on a RPI2, with a LoraHAT board mounted running this ttn gps script as my test output source (GPS output) to the TTN gateway

Both node and gateway set up on the TTN network, with the right Device Address,Network Session and App Session Keys

The gateway is showing as connected on TTN-I can see some messages coming in. I see a few messages from my node, but very hit and miss. When looking at the logs on the RPI3 gateway, I see messages now and again-I am not sure if they are from my node (they are about 3 foot apart on my workbench)?

Oct 11 12:59:32 RPI3-1-Home-Stretch dual_chan_pkt_fwd[1279]: CE1 Packet RSSI: -120, RSSI: -119, SNR: -11, Length: 6 Message:’…xf…’

Oct 11 12:59:32 RPI3-1-Home-Stretch dual_chan_pkt_fwd[1279]: rxpk update: {“rxpk”:[{“tmst”:3023084097,“freq”:868.3,“chan”:1,“rfch”:0,“stat”:1,“modu”:“LORA”,“datr”:“SF7BW125”,“codr”:“4/5”,“rssi”:-120,"ls

I am sure I have the right frequency settings (868.1 & 868.3Mhz) for both devices and both use SF7. The node says connected on the TTN console as well, but no data

My understanding is that my gateway will only be a 2 channel device-which is frowned upon/not the standard-8 channel is the way to go so nodes don’t need to be locked down to specific channels? But before I go down the route and the expense of a 8 channel device, I would like to try it out with my set-up-and that’s where I’m falling down-with all the work I have done I would have expected to see a constant stream of messages between my node and gateway. Am I expecting too much because

a) its not a 8 channel gateway so TTN will mark me down?

b ) there is a limit on the node for how many messages I can send a day?

I’ve spent a week on this, looking at Youtube, going through the forums, reading up on blogs-what am I missing, what else should I be checking?

Thanks

cabs


(Jac Kersing) #2

3 feet is too close. The transmission will be too strong for reliable reception. Use at least 10 feet.

Given the RSSI values in your message I don’t expect those packets to be from a node at 3 feet. Or the antenna on either the node or the gateway is bad, very bad…

a) no.
b) read the fair access policy. Is not enforced but as you seem to be receiving other transmissions you will be interfering with other users if you do not follow it.


(LoRaTracker) #3

Agreed.

RSSI is about 60dB adrift of what it should be.

That sort of reading at 1M is indicative of a shorted antenna, a terminator in place of the antenna, or a transmitter that is blown (which it could be if it was operated without an antenna connected)…


(Cabsandy) #4

Morning.
Thanks for the reply guys, in that message is there part of the message which identifies the sender-or is that encrypted? (I was thinking of the MAC address, or part of it). On the part about transmissions from other nodes, would the gateway not send it onwards to TTN, if said node was on the same frequency?

I’ll move my node and bring in a spectrum analyser from work so I can gauge the TX strength of my node. Looks like I have some more work to do

Thanks

cabs


(Cabsandy) #5

Hi there
Thought I would give you an update on what I found, as you took the time to reply to me. One issue I found was that I had taken code from Github for the single packet forwarder that had the Australian freq plan baked in-as I am in the UK, and the gateway I had set up was listening on 868Mhz…so sorted that-and I have now much more healthier RSSI readings.
I still don’t see any replies on my devices (under Applications on the TTN console)-but I am putting that down to the fact that the TTN sees this as a single channel gateway-and therefore wont forward anything on the downlink? So looks like I am in the market for a 8 channel gateway :slight_smile:

I also ran some range tests- admittedly, I am only using 2dBi 4 inch antennas on both the node and the gateway-and managed -103 RSSI LOS over just 1km-but would have hoped for better? Do the “proper” 8 channel gateways have better sensitivity than these Uptronics/Lora HAT boards?

Cheers
cabs


(Jac Kersing) #6

They might. Placing the gateways antenna at the right location is the most important step to improve coverage:

  • Outside
  • As high as possible
  • No obstacles near the antenna
  • Free view of the horizon (no big buildings shielding the antenna at one or more sides)