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having read that meshtastic section: I mostly agree with their requests tbh. the only suggestions in there seem to be "use full duplex" (with approximately one

by Groxx 10mo ago

having read that meshtastic section: I mostly agree with their requests tbh. the only suggestions in there seem to be "use full duplex" (with approximately one reason why, though it's a good one) and "solve frequency discovery with SDR" which they've already addressed as somewhat ridiculous - because it is, for someone interested in a low power and low cost network. particularly the SDR stuff, which is the VAST majority of that section. this is not at all the same target audience as meshtastic: >A computer with “sufficient” compute power and RAM, to run the ka9q-radio software. KA9Q has stated that a Raspberry Pi 4 is sufficient, and now we have the Raspberry Pi 5 with up to 16 GB of RAM, for only $120. that's like suggesting the way to fix a wireless problem is to use a wire. otherwise the criticism seems to summarize as "it's slow and bad" and well. okay? that's hardly constructive, whether or not it's accurate. the whole thing reads like "the solution is left as an exercise to the reader ;)" because it sounds like it's written by and for people who are already experts and just want to read a cathartic list of flaws they already know. and/or "buy better hardware lol". it's not at all the logical slam-dunk that you seem to think it is.

bb88 10mo ago
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/ http://data3.caprockweather.com:8073/ Each vertical line is one message 150hz wide.
- Groxx 10mo ago
  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 10mo ago
    > 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.

by Groxx 10mo ago

bb88 10mo ago

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/ http://data3.caprockweather.com:8073/ Each vertical line is one message 150hz wide.

Groxx 10mo ago
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 10mo ago
  > 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.