i am testing the T1000-A (HW v1.6 / SW v2.5) on TTN and i am wondering about how it behaves with the ADR (Automatic data rate) mode on or off.
With ADR turned ON the T1000 the device can only communicate with the gateway when it is in close range. I noticed that it only sends messages with the lowest spreading factor (SF7BW125), so obviously this means it is limited in the transmission range.
So switching ADR OFF and setting the DR fields to range from DR0 to DR4, the range greatly increases as it will now send messages with higher spreading factors. However it seems as if the device is randomly picking the spreading factors for each transmission.
Is this a known behaviour and if so, what would be the recommended settings to achieve reliable communication while optimizing air-time?
LoRaWAN typically prefers low-spreading factors for faster communication. The device will use the lowest spreading factor (SF7) to maximize data rate and minimize airtime, which is efficient for short-range communication but limits the range.
of course a device ideally uses the lowest possible spreading factor to minimise airtime, i fully agree.
However when configured to use ADR, according to the Lora specification, i would expect the device to start with an uplink at high SF until the ADR algorithm requests the device to reduce the SF.
Likewise when configured NOT to use ADR, i am wondering about the logic the T1000 is applying when sending at random spreading factors. But at least it should be possible to limit the SF range using the configuration parameters.
Hi @rusheee, it’s quite common for trackers to use a random selection for the SF when not in ADR mode, as they’re expected to be moving and therefore are typically not good candidates for ADR. ADR can work well if they move often but within a contained area where the selected datarate works for the whole area, or if they tend to move rarely and you’re interested in where they end up, not the actual route (for asset tracking as an example) as ADR will re-establish itself after a short period.
