Node to node Bluetooth? And spreading factor?

Hey folks, just got a tbeam and heltec going on Android phones. Thanks to everyone who got this off the ground, it’s such a cool project!

So first off, I didnt see anywhere if this is a feature, but during my testing it appears that these nodes often send packets to each other without using Lora (I assume via bluetooth?) When first starting up, or when only one node is running, I can see the 900mhz signal on an SDR. But after both nodes are running for a bit in the same room, this goes away and the messages are still passing. I’ll test further, but the reliability is not as good as I had hoped (unsure if this is related?)

Also, what is the spreading factor and bandwidth for the default setting of long/slow? I didn’t see anything definitive on this. But it is sloooooow. On the sdr it looks like most packets TX for about 5 seconds. I saw 3 run consecutively with only a fraction of a second split between. It seems this data rate will negatively affect reliability with heavy use, particularly in a mesh scenario with multiple hops and a lot of messages bouncing around.

Would one of the stock settings be somewhere in the neighborhood of SF10/125khz? This seems to work well for small payloads on Lora.

The mesh is Lora, Bluetooth is just between one device and your phone

Here you go:

Those settings are changing in 1.3 and that’ll be published when it’s ready.

Thanks. Of course now I can’t replicate what I described. I’ll tinker some more. By chance, is TX power throttled when two devices are next to each other with 100% signal?

Thank you! Just saw a transmission on long/slow run continuously for 17 seconds (character limit maxed.) Wow…

1 Like

This is a flood mesh algorithm, not point to point. We need to assume there’s someone at the edge of the possible reception.

I was able to replicate what I described earlier. With normal operation, all of the meshtastic activity is visible via SDR at ~903mhz (long/slow) and ~924mhz (med/fast.)

However, whenever changing channels without resetting the nodes, there is zero activity on the SDR in the 902-928 band, even when sending messages constantly (most of which still show up on both nodes and android phones.) How is this possible?

After rebooting the nodes, normal radio activity resumes. I also checked for radio signal at the Lora antennas with an analog rssi meter. Before a reset, it doesn’t move the needle when passing messages between nodes. After the reset (with no other changes) it pegs at 100%. This seems to happen every time the channel is changed, and then back to normal after reset.

1 Like

this is a known bug.