LoRa band interference 868Mhz (869.525)

Anyone seen anything like this on their area? This seem to be blocking any weaker signal that comes from further away.

Trying to reach the next town from me, I can get good reception from there, but nobody hears me in the next town (this is where the interference is).

Any idea how to mitigate this other than complain to the authorities that someones spamming the band?

it’s basically constantly bombarding the channel. I don’t think this is someone doing it on purpose but possibly some kind of harmonic of other frequencies or maybe a bad antenna connector that’s causing it to broadcast on the wrong frequency. It is however suspiciously right on the dot with EU’s Lora. It ranges from around -20 to -35db

I’ve seen some - very short lived - bursts on the chosen meshtastic frequency on SDR. Haven’t got enough to figure from what.

Note, that it might even be meshtastic traffic, just with different lora settings. You might be using the default “longfast” for example, but that traffic is using some other settings. Its hard to see, but those could be lora ‘chirps’ in your screenshot.
At the very least you can measure the bandwidth of the chirps, and see if are 250khz (default on LongFast) or something else. The chirps look a nice set bandwidth, although admit havent figured out the scale on your image.

The bandwidth looks too regular to be general harmonic interference or similar. But maybe you can carefully match Lora settings to listen to it, but may need to go outside meshtastic devices to be able to see the messages.

It’s nothing like lora and we have very few nodes here. Small town.
I have a video about it so you can hear. I posted it over at Reddit in the hopes of getting some info.

I dont exactly how Mestastic chose 869.525, but is the exact middle of the 500mW, 10% ‘band’ (869.4->869.65)

So it not inconceivable that someone else would make the exact same choice of frequency by accident.

I do agree it not like typical ‘packets’ like meshtastic use of Lora (short bursts), but it could still be still be lora itself.

I know on SDRsharp, really had to slow down the waterfall speed to really see the lora chirps, otherwise they did just look like lines in your screenshot.
(only just got the SDR device so havent tried actully decoding Lora yet, or tried much software)

same here, and some other place nearby…
looks similar, blocking half of the meshtatic bandwith 868 here…
seems to be from some directional antenna !
meshtastic devices that are “in” this signal are almost deaf ! they can send, but not receiving much

Hmm…that looks like an actual transmission as opposed to what I’m getting that just sounds like static. Either way it’s not exactly adhereing to the 10% duty cycle. i.e illegal

i dont know whats static /whats transmission :slight_smile:

its illegal, depending on where you are

you can build an easy directional antenna, and locate where it comes from .

OUt of interest who would you report it to?

In the UK, been looking, appears to be Ofcom, other countries presumably have similar bodies.

Closest found was this

but does say

  • It is unlikely that Ofcom would investigate a report of interference that is not regarded as ‘harmful’. It’s not our policy, and we don’t have powers to do this effectively.

Doubt much can be done about ‘hogging’ on the ISM bands.

in germany we have someone to report to :slight_smile:
Bundesnetzagentur - Prüf- und Messdienst

I’m from Finland. We have a body that governs the use of frequencys and should act if someone interferes / missuses them.
Though I kinda expect something similar to what you found. Why would they care about a small blib on the 868 but I really don’t know how seriously they take these kinda things.

Here in the UK the PilotAware safety system uses the same 869.25MHz frequency as Meshtastic, so if you live anywhere near an airport you might be seeing interference from that.

Pretty stupid having two things on exactly the same frequency, but I suspect that given the safety critical nature of PilotAware and the increasing uptake of Meshtastic our little hobby will cause them more problems than the other way round!

1 Like


Do you know if anyone checked that meshtastic on 869.25MHz is permitted ?

The original post was about 869.525Mhz, so that looks like 500mW at 10%.

IRE 2030 (the regulatory document for the UK) does have a general allocation from 868 to 869.7Mhz, but you need to check you are not causing interferance or use a duty cycle of less than 0.1%.

869.25Mhz is reserved for alarms; and on the band end of Social Alarms. Reference ERC RECOMMENDATION (70-03) Page 26 - 3700 (cept.org)

There was a typo in my reply. Meshtastic uses 869.525MHz, not 869.25. So the alarm restriction doesn’t apply.

Both Meshtastic and Pilot Aware share the same 869.525mhz frequency.

Apologies for the missing 5!

1 Like