[bb88]

Meshtastic can only use one frequency at a time. So, say, a battery status update can stomp on a message trying to get to a meshtastic router. (He's got the link to the hidden node problem with a great wikipedia article about it).

The more popular the network, the more frequent these message stomps happen. Flood routing makes these stomps more frequent.

There is also no end to end packet acknowledgement system like tcp, so at hop 3 (e.g.) if the message got stomped on, who would know?

Let's say someone made a dual band lora transceiver. Well that would help, but it wouldn't solve anything else, because there's still core routing/reliability/topology issues.

So if you had 20 channels to talk over, well that would be even better. The chance of having your message stomped on would go down significantly making the network much more reliable. That's the SDR part (the listening of 20 channels at once) vs the Lora chip which can only listen/transmit on 1 channel at once.

Edited to add:

"But that's super expensive hardware/engineering to do that!" you might say. Well, it's being done today.

The point is that if you can fit 20 1khz channels in a 20khz RF space. The 20khz RF can be converted into audio and fed into a soundcard and processed. This exists today with FT-8, though FT-8 uses 150hz bandwidth per stream in 2.8khz sections per band.

You can see some FT-8 activity by looking at some websdrs.

Maybe go here and tune to 14.074Mhz Upper Side Band (USB)

http://data3.caprockweather.com:8073/

Each vertical line is one message 150hz wide.

[wtallis]

I still don't see how your suggestions amount to anything other than telling people to spend a lot more money on completely different hardware and use it in a completely different manner.

FT-8 doesn't seem usefully relevant here. The fact that the bandwidth is so low that it can be sampled with a sound card isn't at all helpful when Meshtastic doesn't require a PC. And FT-8 carries minimal payload (typically amounting to no more than the automated status updates you dislike Meshtastic wasting airtime on), and I've never heard of anyone doing routing over FT-8. You're just making noise about a completely unrelated niche radio hobby.

If the constraints of LoRa and Meshtastic don't make it possible to implement the kind of radio system you want to play with, that doesn't prove that Meshtastic has made any wrong decisions. It just says you would get a more fulfilling experience from getting into a different radio hobby, and stop getting in the way of potentially productive discussions about how Meshtastic could be improved within the constraints of the currently-existing commodity hardware.

[bb88]

> FT-8 doesn't seem usefully relevant here. The fact that the bandwidth is so low that it can be sampled with a sound card isn't at all helpful when Meshtastic doesn't require a PC.

This is what I meant about adding noise to the argument. This isn't a useful argument. FT8 could be decoded with a microcontroller. But you wouldn't know that. And it only shows your ignorance of the subject.

Meshtastic maximalists are the true believers, throwing away the decades of experience and knowledge because they drank the kool-aid of the leaders that think they are smarter than the folks who have been doing this for the last 40 years.

[immibis]

Why does this pattern come up so often? Something is promoted ignoring the lessons of the past and claiming not to have those problems, then it's discovered that it does have those problems and that ostriching didn't solve them (surprise) and that ostriching made it even worse than if they'd left a TODO placeholder

[bb88]

There is some issues with "boomers" and "toxic culture". Ham radio can be pretty toxic -- but you have to find the groups that have the knowledge but don't have the toxicity. There is a stigma to being a Ham these days -- often well deserved I think. You can find lots of youtube videos of toxic hams on the air. Or you know facebook forums.

But those people aren't the experts typically. The experts have their own community, friendships, etc. They'll be super nice, and they might speak up, but they expect to have polite conversation. And if the forum is a shit show, they'll take their expertise elsewhere.

[immibis]

The message would be 20 times longer (in time), increasing its chance of collision by 20 times and exactly cancelling the 20 times reduction that it gets from randomly selecting one of 20 channels.

[bb88]

If you're monitoring 20 channels, which you would need to do anyway, you'll know which channels to transmit on.

[immibis]

But that's also true on 1 channel. Doesn't solve the hidden node problem. You have 1/20 as much risk of starting to transmit at the same time on the same channel as someone else, after you both determined the channel was clear, since that's a race condition with a fixed time window per transmission, but is that the main cause of collisions?

[bb88]

Here's a thought experiment. Remember, there's only one channel.

Let's say you have 100 meshtastic nodes in a residential valley. And you have 1 meshtastic repeater up on a mountain overlooking the valley (or it could be on a radio tower or water tower, say).

So it's clear that most of these nodes won't see each other because terrain, housing, trees, etc.

But it is possible that the repeater may have clear line of sight to most of them. And that's where the hidden node problem lies.

And adding more nodes and more repeaters is not going to help. The problem is either solved by increasing the number of channels (hence the sdr angle) or by time division multiplexing the single channel and coordinating who can talk at what time. The first is easy. The second is much harder.

[Groxx]

yeah, that's exactly what I was referring to as "use full duplex" (use at least 2 frequencies, I agree this sounds like pretty solid critique (particularly with meshcore's network setup) and wouldn't make hardware dramatically more expensive) and "buy better hardware lol" (use 20+ frequencies and make it a completely different product at a MASSIVE price increase. why not just suggest wires then).

so there's one bit of probably-usable advice (slightly raise cost for significant benefits) and one that completely misses the point (charge at least 5-10x more for wildly different hardware, use hundreds of times more power, etc). the article spends several times more text on the latter.

flood routing and lack of end to end ack I also agree with, I sincerely doubt those are the best options and if user complaints are any sign then I think it's an existence proof that it doesn't scale, exactly as predicted. neither are part of that article, though it is in a linked also-large mastodon thread, which has basically just one constructive suggestion (8x the channels, though they don't think it'll work either) and many "this sucks" examples (flood fill, hop limit, etc. it amounts to "do better", not "X is better, learn from it").

[bb88]

> charge at least 5-10x more for wildly different hardware, use hundreds of times more power, etc

So I think what's super interesting is that it not necessarily need to be 5-10x more, nor needs hundreds of times more power.

I'll start with the power argument first.

WSPR (pronounced "whisper") often uses 100mW transmissions and can be heard across the globe in the HF spectrum. The techniques for reception can pull the signal out of the noise. It's common for weather balloons to send telemetry this way. People use it to monitor band conditions as well.

The trick is that WSPR puts all the power into one signal approximately 6hz wide. That's why it's so efficient, and one reason why it can be heard across the globe with such low power. Now you're probably not going to get that distance in the 900Mhz ISM band, but you will be heard further if you so choose (or need to be).

As per cost?

100mW assuming a 75ohm antenna (dipole) is 36mA of current. For 1W (which is roughly the ISM limit) it's 115mA of current, so the components won't need to be high power, probably jelly bean parts.

The RTLSDR is $25 bucks with 2.4Mhz bandwidth which is way overkill for this.

Lots of microcontrollers are cheap.

There's engineering cost and time, sure, but Meshtastic did show that a need for reliable mesh low power messaging exists even if it's not the final form.