RAK 7200 reporting only stationary

Issue: RAK 7200 can’t send packets to TTN while moving

Setup: RAK7200 connecting to MikroTik LoRa8 GW

Server: ttn eu

Details: I started to measure LoRa coverage in my region with RAK 7200 tracker. Sadly - when I’m very close to my gateway (like 1000 meters) everything is OK. But when I drive further from it I can see traffic on my TTN app only when I stop (or slow down to 20km/h or so). What can be the issue?

Hi @rolfo,
Is this a 1km line of sight?
Could you provide some downlinks from TTN so we can see the SNR and RSSI values?
Also the response of “at+get_config=lora:status” to check if there are any problems with the node’s configuration.
The node should be with a disabled ADR function.
Also, the speed that you are moving with may be the problem.

There are issues with the way that radio propagates & reflects that can cause uplinks to be scrambled just enough they fail CRC.

Or words to that effect, I can’t find the original post where it was discussed.

Given allowed message intervals on TTN, driving is probably not a good way to do mapping, at least unless you have something like a mountaintop gateway overlooking a large flat area as in more typical circumstances a car would have you moving between coverage and non-coverage too quickly for packets spaced as widely in time as required to be able to capture.

You might start by walking or riding a bike.

1 Like

at+get_config=lora:status

Work Mode: LoRaWAN
Region: EU868
Send_interval: 30s
Auto send status: true.
Send_interval work at no sleep
Join_mode: OTAA
DevEui: XXXXXXXXXXXX
AppEui: XXXXXXXXXXXX
AppKey: XXXXXXXXXXXX
Class: A
Joined Network:true
IsConfirm: unconfirm
AdrEnable: false
EnableRepeaterSupport: false
RX2_CHANNEL_FREQUENCY: 869525000, RX2_CHANNEL_DR:3
RX_WINDOW_DURATION: 3000ms
RECEIVE_DELAY_1: 1000ms
RECEIVE_DELAY_2: 2000ms
JOIN_ACCEPT_DELAY_1: 5000ms
JOIN_ACCEPT_DELAY_2: 6000ms
Current Datarate: 5
Primeval Datarate: 5
ChannelsTxPower: 0
UpLinkCounter: 6162
DownLinkCounter: 0

I doesn’t matter if it is line of sight or no. ADR is disabled. So to conclude - can you confirm that the speed can be issue?

The problem is not the speed itself. As @cstratton said the problem may be that you are moving between areas with coverage and areas with no coverage too quickly, due to the speed. The effect is that the node dont have enough time in the coverage zone so the whole packet to be captured.

It actually matters. If you have a complete line of sight for the full test field that will eliminate the possibility for the node to move too fast from coverage to non-coverage areas.
Try to take a walk with the node on the same road and see if the problem remains.