Comment by AlphaWeaver
18 hours ago
The "100x bandwidth" claim needs to be substantiated.
There are some significant regulatory issues with the current popular mesh network protocols in the USA, namely that neither MeshCore or Meshtastic are compliant with the actual FCC regulations. 100x bandwidth because you're breaking the rules isn't the same as 100x bandwidth legally.
Here is the issue discussing this in the MeshCore repository: https://github.com/meshcore-dev/MeshCore/issues/945
I never understood the popularity of these protocols, because when I looked at the legal duty cycles and multiplied that by time in a day and instantaneous bitrate, the result was a disappointing amount of data per day...
So many spectrum rules are totally weird though: should they be interpreted per radio device? or per user?
What -apart from cost- prevents a user who wants more bandwidth from installing 10 devices in parallel and alternate each radio so none of the radios exceed their allowed transmit duty cycle?
> What -apart from cost- prevents a user who wants more bandwidth from installing 10 devices in parallel and alternate each radio so none of the radios exceed their allowed transmit duty cycle?
Folks with badges knocking on the user’s door. It is pretty trivial to locate stationary signals.
The issue you linked to is about MeshCore using channels that are too narrow. A mesh system claiming to offer 100x bandwidth is probably not violating regulations in that particular way.
Correct. The LoRa configurations mentioned which offer 100× the speed of Meshtastic/Core operate at 800 kHz and 1.6 MHz bandwidth, which are permitted by the FCC in 15.247.
As far as I know there's not actually anything particular to 2.4 GHz allowing higher throughput for LoRa than that the corresponding Semtech chip happens to support wider bandwidths. (I.e. no legal barrier.)
The tradeoff is less range due to lower link budget. Doubly so because 2.4 GHz has higher free-space path loss. You're not going to get outside your house with these speeds. The primary use (as stated in the original post) is likely through clear space with a directed antenna.
(The 2.4 GHz band is better suited to this use since you can use antennas with higher than 6 dBi gain. If my math is correct, anything higher than 11 dBi is a win even accounting for FSPL and the power derating the FCC imposes.)
(Aside, I am the author of that MeshCore ticket.)
At least in Europe the 868 Band is is in contrast to 2.4 allowed only for low duty cycle applications that do not actually occupy the channel for more than 1% afaik (given space multiplexing). I also remember also that the free to us band was quite narrow by design (we built sensor nodes bit banging a PHY transceiver that were in the grey area of unenforced rules, 20 years ago .l)
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What issues does it create for others to use too narrow of a bandwidth? Why “should” the FCC care if someone is only using a small portion of the spectrum that would otherwise be fine fr them to use?
Thanks for educating us!
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There are more rules being broken. For example, overusing the frequency which effectively prevents others users from sending messages.
In the end, won't be used.
In the EU, the duty cycle limit is like 10% per hour. North America doesn't have that restriction...
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i am just reading "its not allowed" "rules are being broken" "not premitted" lol. how should you invoate and break free from the current ISP model, if everythig is not premitted?
That's just "using lora in the same band as WiFi and Bluetooth" no?
The 915 MHz, 2.4 GHz and 5.8 GHz bands are regulated in the US largely in the same manner, see https://www.ecfr.gov/current/title-47/chapter-I/subchapter-A...
At least the start of the discussion is around the 915 MHz band which is not WiFi/Bluetooth
Seems more of an issue of outdated and de facto unenforceable regulations than an issue with the protocol.
> de facto unenforceable regulations
I guess you have never encountered the anger and wrath of a retiree who's into ham radio and has the regulatory office on speed dial.
In the U.S. I believe the FCC has federal authority to knock down your door, if they can pinpoint an illegal interference emanating from within your home. Intent is not particularly a factor in that, since interference can have a large radius and be unintentional. Seems like an awful time to be intentionally emanating ‘de facto unenforceable’ illegal signals.
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"regulatory issues with the current popular mesh network protocols in the USA"
There are other countries in the world.
And there are also places where there is no electromagnetic policies (think about over the oceans).