[AlphaWeaver]

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

[wtallis]

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.

[colanderman]

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.)

[riedel]

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)

[sandos]

Nobody uses the 1% bands afaik, there are 10% duty cycle bands.

[nerdsniper]

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!

[colanderman]

Spectral power density is the primary concern.

The legal power limit in these bands is 1 W. If you spread that out over 500 kHz, that signal is weaker than background noise at any given frequency for anyone more than about a city block away. (Give or take many factors.)

But, if you compress that 1 W into, say, 12.5 kHz (typical for FM voice), your signal is now detectable (and will interfere with other, possibly licensed, users) at over 6 times the distance.

There are probably other factors. For example, it's not legally sufficient to simply reduce your power by a corresponding factor. I suspect it may simply be the FCC's goal to reduce conflict between users by mandating spread-spectrum technologies for unlicensed use.

Note also that 47 CFR 15.247(e) [1] gives a spectral power limit which corresponds approximately with the 1 W max / 500 kHz min specified in (b)(3) and (a)(2).

Final side note – https://docs.fcc.gov/public/attachments/FCC-02-151A1.pdf is interesting reading as to how the current form of 15.247 came to be. Specifically it changed the rule from specifically DSSS to digital modulation generally, which in turn allowed the transition from 802.11b (DSSS) to 802.11g (OFDM) on 2.4 GHz.

[1] https://www.ecfr.gov/current/title-47/part-15/section-15.247...

[codys]

The idea with either requiring very wide band or frequency hopping on the 900Mhz band is to make it so that usages of the 900Mhz band 1. are tolerant to some loss (ie: by temporary collision) and 2. don't collide continuously (by using wide band or frequency hopping).

It's a mechanism to try to make the 900Mhz band more useful to uncoordinated users.

[nunobrito]

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.

[nubinetwork]

In the EU, the duty cycle limit is like 10% per hour. North America doesn't have that restriction...

[nunobrito]

Ah, thanks. Had the idea the duty cycle restriction would be common.

Thank you for the update.

[Joker_vD]

That would violate the First Amendment. /s

[mytailorisrich]

I believe that they usually have a maximum dwell time, thoughs sometimes over a specific period (in which case it it equivalent to duty cycle)..

[slow_typist]

Not on the 2.4 GHz band though

[nubinetwork]

Our local discord questions the use of 2.4ghz for longer than 50 feet, between WiFi and Bluetooth, microwaves, and millions of "2.4 GHz (nonspec) wireless devices", the spectrum is just trashed.

[subscribed]

Halow works though.

[slow_typist]

For lora applications or in general?

[ingohelpinger]

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?

[DoctorOetker]

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?

[mapt]

These things aren't "Internet Access", they're an easy way to get service that is bandwidth-equivalent to SMS, MMS, IRC or walkie talkie, over complex and distant terrain, without any central coordinating authority. Potentially even acting as last-mile to repeater nodes that pass through the actual Internet. This is a terrifically useful idea of a network in certain conditions, though in other conditions it's probably just going to be last-mile for your personal Gmail account.

[DoctorOetker]

I didn't assume "internet access", even for machine 2 machine applications, it was a disappointingly low bandwidth.

I don't deny a niche of applications, I tried to understand its popularity, and back then I came to the conclusion it was probably illicit use of the technology, not conformant use.

[jasonwatkinspdx]

The people I know playing around with it are interested in something that offers very basic SMS style broadcast without any centralized authority or infrastructure.

For example here on the west coast we have a non trivial probability of earthquakes big enough that a lot of infrastructure may be down for weeks.

Another motivation is political. We've already seen efforts to restrict people's ability to warn others about ICE's activity. So I know some people that while not going full revolutionary or anything, are interested to learn about some peer 2 peer alternatives as a sort of hedge against things getting worse.

And some people just play with it because the tech is neat, it's fun to see how far your messages can get, etc.

[pstuart]

I'd assume that the ability to communicate without depending on cellular service could have a certain appeal.

[davemp]

> 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.

[andruby]

The point they are making is that if the limit is _per device_ than using 10 devices doesn't break the rules.

[davemp]

The FCC or whoever is almost 100% just looking at power/time/location. Those 10 devices will look like 1 device.

[DoctorOetker]

when would the 10 radios be sufficiently spaced to count as separate devices?

[Zigurd]

Law enforcement that isn't solving 50% of murders also isn't looking for exotic crimes unless there's a lot of money in it for them.

[UltraSane]

Meshtastic routing is also completely broken.

[adev_]

> Meshtastic routing is also completely broken.

I am curious about that.

What is in particular broken ?

Any reason why Meshtastic is not using a well specified / tested a mesh aware routing protocol like BATMAN [1] ?

[1]: https://en.wikipedia.org/wiki/B.A.T.M.A.N.

[wtallis]

I suspect protocols like B.A.T.M.A.N. would consume all available LoRa airtime just with neighbor discovery. On Meshtastic, nodes announcing their presence more than once per hour is seen as unnecessarily talkative.

I also don't think it's possible to make Meshtastic into the kind of reliable and high-performance mesh network some users want without effectively dropping support for most battery-powered devices by requiring much more frequent transmissions to maintain connectivity and participation in the mesh.

[adev_]

> I also don't think it's possible to make Meshtastic into the kind of reliable and high-performance mesh network some users want without effectively dropping support for most battery-powered devices

Interesting.

Zigbee has this distinction between router node and non-router node.

Routers are active members of the mesh (relay). Non-routers are just clients.

Most battery devices in Zigbee acts generally as non-router.

It is surprising that Meshtastic did not follow this pattern. Zigbee is not a young protocol.

[sandos]

Meshtastic did, in a way. There are roles and settings to disable rebroadcasts, then you are effectively a client. And it is used to preserve battery.

[rocqua]

That's just "using lora in the same band as WiFi and Bluetooth" no?

[colanderman]

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...

[Neywiny]

At least the start of the discussion is around the 915 MHz band which is not WiFi/Bluetooth

[RobotToaster]

Seems more of an issue of outdated and de facto unenforceable regulations than an issue with the protocol.

[st_goliath]

> 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.

[altairprime]

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.

[zoobab]

"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).