By default theRAM4270 is shipped with Channel TX Power = 0 and DR = 5
When monitoring the Transmit Power of the RAK4270 it is over 100mA (at 3.3V) and but ADR downlinks from the server bring this down to 70mA after 60 or so uplinks
This is performed without any MCU host intervention.
Other Lora Sensors that we have looked at have a much lower Transmit Power (approx 35mA) with the same LORA Server (same distance from the LORA Server)
Can the Host MCU simply change the TX Power Setting in the RAK4270 to reduce the Transmit Power or should this be reduced along with the DR setting ?
Should the LORA sensor start with a lower transmit power setting and then increase the transmit power if the Join Request is not successful ?
If the LORA sensor does not get a successful Join Request when on Maximum power what if the best action to perform ?
Generally the Network Server ADR implementations increase the DR until it can’t be changed further and then change the power level - the first priority is to reduce airtime for the benefit of all.
There is less focus on the power level and more on the DR. In theory you could come up with a Join scheme that starts on something suitable for the deployment, say DR4 and quickly escalate it down to DR0 if no join accept is heard. But I think you’d have to get in to using the RUI development environment to have that level of control.
You can also turn off ADR once you have a join & look at the downlink RSSI & SNR to do your own ADR tuning. Or leave it on but have a verification scheme of which I’ve written about on the TTN forum - which in summary is something like every fortnight do a confirmed uplink to check everything is OK and on the other week anticipate a downlink message from your application. If neither of these occurs, then turn off ADR, reduce the DR each time you uplink with confirmed on until you get a response, if you hit DR0 then after a couple of times do a join, if no join-accept wake up at random intervals to try to see it the gateway has come back or if it was IOT Armageddon.
For joining, you will use max TX power. This is fine since you will only join once (ideally) on your device lifetime. On the succeeding uplinks, if you turn on ADR, then the device will adapt based on the network server command. If you want control on the TX power, you have to turn off ADR and control the TX power after a successful join.
This is not yet the final FW and the team is still doing some validation test. Doing good so far. You can evaluate this. Soon a new FW will be uploaded in our download site. The changelog is also here.
