Marcio, Jr..
Marcio, Jr.Hello,
I’ve been experimenting with the sync word configuration and I can’t get a clear picture.
Multitech’s conduit only accepts the values 0x12 (private) and 0x34 (public), but others devices can accept any arbitrary value. Unfortunately the documentation isn’t very clear about it. SX1272 and SX1276 datasheets clearly tells about the “Packet Filtering based on Preamble Start” which makes me think that if device’s sync word doesn’t match the gateway’s sync word the packet won’t be received once the gateway will discard it after the preable.
Other people mention that the only acceptable values are 0x12 and 0x34 – it seems to be Multitech’s belief also – and setting it differently could cause unpredictable behaviour.
On my tests, what I got was: using the same values (0x34 or 0x12) on device and gateway makes it work perfectly. But, setting values differently results on 10% – 30% success receiving. I can’t understand why !!!
I got similar results with other brands.
Does anyone knows how this actually works? Can I use any arbitrary value? Can I rely on this sync word in order to achieve a packet filtering?
Thanks in advance !
Jason ReissWhat was the range used between the end-device and gateway?
What is the success ratio at +50m?
Perhaps the preamble sync-word detect gives some false positives when the signal power is very high.
I have seen ~10% success with mismatched sync-word as well when testing at my desk at close range.
Marcio, Jr.Yes, those tests were taken on very close range (under 10m).
Many tests results on 5% – 35% false positive. One specific configuration shows 80% false positive.
Anyway, is this really suppose to provide a packet filtering capacity?
I mean, setting my gateway to, let’s say 0xA5, should make it forward only messages from end devices matching this word?
Thanks.