The hard RAK831 cafe part 2

Interesting, I am wondering how does itfix to the board, thermal paste also required?

I would guess thermal self-adhesive tape would be used because presumably there are no mechanical mounting points.
On the right picture, the pink-brown material (2 pieces) under the heatsink appears like it is not sticking to anything.
The material has to perform three different functions:

  • As electrical insulator to prevent short-cutting the PCB
  • As heat-resistant glue to mount and keep the heatsink onto the PCB
  • As thermal conductor to transport heat from the PCB to the heatsink.

The heatsink is wider than the PCB. This increases thermal performance but also makes it mechanically less robust and more sensitive to shocks and bumps (and does not help cool the Raspberry Pi MCU).
I’m curious how they are going to attach it.

It seems that RAK wireless copied the datasheet of iC880A. Typical chinese way of doing business…

I’ve found this link :blush:
AliExpress Link - Rak Wireless Store

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Hi I have had my gateway for a few months, I know that indoor placement with a little whip antenna is not the a good solution. We have quite poor mobile phone coverage as we have gypsic plates with silverfoil in our walls - but anyway I would expect some TX signal going to my gateway that should sniff some RX. So I need some help to debug
What to do?


This looks al perfectly healthy, do you have a node near the gateway? (Not too near, 3-5 meters distance should work)

Thanks for a quick reply. Well I don’t have any nodes myself, so I thought that I would receive data from other nodes when they transmit?
I would expect from that I would receive adn forward some node-packages

Now when I look into my log, then I see that It looked like that I have received something, but I got CRC fail
Can this behave due to poor antenna reception?

Could be the signal level is too low to receive an undamaged packet. Could be the received data is not a valid packet at all.

Best way to test is to obtain a node and try to send data :smile:
The ttnmapper data could have been obtained last year so your gateway had no chance of receiving it. However the antenna and its position inside a faraday like room will not help. If possible you could position the gateway outside (when it’s dry) for a couple of hours to see if that makes a difference.

I have been thinking what could interfere with 868MHz and I somehow wasn’t thinking of my Zwave devices for homeautomation, they also operate on ISM band

I need to extend my Ethernet cable to the garage away from my house, to check if I then can receive some good data packages from somebodies node

@TonySmith In my country, the 868MHz frequency is forbidden but I see its popularity in the world :slight_smile:

So you are illegally using that frequency in your country and the TTN network.
Off course we don’t approve that.

Has anyone programmed RAk831 with ESP8266 or other MCU? I want to deep understand about communicating SPI between RAk831 and raspberry pi. I reading Lora packet_forword but I have a problem when converting SPI of raspberry Pi to SPI of MCU.

please explain… what did you use as MCU… what did you exactly convert and where can we see the converted code ?

hi BoRRoz. I use STM32 to connect RAK831. I want to know what did raspberry pi write/read into the address of RAk831 but I don’t know about SPI of Pi so some line in code I don’t clear.

I don’t know why I am not able to send anything from my RAK831 Gateway to my RFM95 node using util_tx_test.c program (from as plain LoRa packets. Nothing gets received on the node(using Radio Head library on node).

The log on the RAK831 is fine:
Sending 10 packets on 868400000 Hz (BW 125 kHz, SF 7, CR 1, 16 bytes payload, 8 symbols preamble) at 14 dBm, with 100 ms between each
INFO: concentrator started, packet can be sent
Sending packet number 1 …INFO: tx_start_delay=1495 (1495.500000) - (1497, bw_delay=1.500000, notch_delay=0.000000)

Things I checked:

  • Tested inverted modulation from gateway.
  • Changed SyncWord to 0x12 on end node and set loraWAN_public=false in the code.
  • matched frequency, CR, SF, BW, preamble.

I can send from the RFM95 node to the RAK831 gateway using util_pkt_logger without any problems. I also tried with another Dragino-gateway that could send to the end node without problems, so the end node is fine.

What could be wrong?

Thanks in advance!

Picture from RAK831 + RPi Converter + RPi from the RAK Wireless Module Store.

That GPS antenna picture is truly creative. :wink:



2 questions,
Has anyone got some pointers on how to change the packet forwarder to the TTN one on openwrt?
I keep getting “Failed to start concentrator”. About every 5th attempt does start it and then everything works ok. At the moment I am just testing the system and am using the leads that came with the system to join the MCU board to the Rak board. Could this be the cause? and if so are there any ways around this apart from using a PCB to link the two? I have already tried changing the SPI speed but it made no difference, although I might be changing it in the wrong place.

I just ordered one, looking forward to contributing because there are so few open gateways in Vancouver Canada.

these two writes up sold me:

I thought I’d try some of the packet forwarders, both of these are well liked/used on things network? ~/ic880a-gateway

and… is there a command line flag to run the packet_forwarder without the radio module, just to send a test packet to things dashboard?

all the startup guides begin with new image, is that really necessary? easy to enable SPI on most pi’s.


-yes preferred methode… and then update

use your first link to start
or look here for more tutorials.