Advanced Meshtastic - LoRa Configuration
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- เผยแพร่เมื่อ 4 ม.ค. 2024
- Welcome to part three in the Advanced Meshtastic Series where we continue going over the Radio Configuration settings and take a deep dive into LoRa and the Chirp Spread Spectrum it uses that allows for long distance communications at low power.
More info on Meshtastic can be found at
meshtastic.org/
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Good videos on LoRa
• How LoRa Modulation re...
• LoRa/LoRaWAN tutorial ... - วิทยาศาสตร์และเทคโนโลยี
It always just blows my mind that this level of presentation and knowledge is available to all for free. Thank you for taking the time to make these videos.
Sure thing! I hope the videos have been helpful!
This was a great explanation! I loved the use of SDR to demonstrate the various parameters. I'm impressed that the Meshtastic app allows this much control over the configuration. Among other things, this provides a bit more privacy when configured to a nonstandard configuration. Even though encryption protects the contents of the message, sometimes I may not want people realizing that I'm communicating even if they don't know what I'm saying. 902 to 928 MHz are available for ISM in the US.
Thanks! It was a fun video to make and cool to see on the SDRs waterfall!
Great explanation of LoRA parameters! ♥
Thank you!!
I've had an interest in Meshtastic for over a month. after watching many videos on it. I did build a tiny 915 MHz ground plane antenna connected to my RTL SDR monitoring the frequencies between 902 to 928 MHz and found many, mostly 200 KHz wide blips in varying signal strengths which look and sound like those speeded up chirps on your video, a good sign there is local Mesh action in my area.
You are very good at explaining things. Thank you.
Glad it was helpful!
Man you are just killing it! Thank you!
Well done. Very useful.
Good stuff! 👍
Appreciate it! Watching your video now. Great info!
Thank you for putting all this information together for us!
Sure thing! Glad you're finding the videos helpful!
Thank you for posting all this. Received some Heltec v3's the other day and have been trying to interact with the local net. Feared it was bad settings somehow.
Excellent job.
Thanks!
Wow, an amazing amount of info and explanation.
Thank you! I'm glad you found the video informative!
Got my t echo in route. Thanks for this series!
Nice! Sure thing! I'm glad you're enjoying the series.
T Echo & T beam supreme are on the way from China. I built two yagi antennas and did not manage to have a connection btw Antibes and Nice over the sea. I currently have old version of tbeam 0.7....
Great explanation, many thanks.
Glad it was helpful!
Thank you!
Great job. Will link this video.
Awsome. keep them coming. This is the info I need.
Appreciate it! Will do!
Thank you very much indeed for this series. It helped me getting started. I have a few more boards en route. One headless router and / or repeater will be placed at the local makerspace shortly. Maybe I can get few more started in other places.
Thanks again! 😊
Sure thing! I'm glad you're finding the series helpful! That'll be a nice setup 😃
Great informations. Thank you very much...
Sure thing! I'm glad you found it useful!
Excellent vid
Thank you!
Nice!
Great Video and explanation. Could you please make a video showing just how you were able to make the bandwidth changes on the fly? Looks like you're using an arduino program to make the changes but how is it connected to the radio. Would be interested into seeing how you actually set that up.
Thanks in advance,
Thanks!
Thank you so much for the support!
Thanks
Sure thing!
Nerd stuff at it's finest! Thank you for the great video.
Sure thing!! Glad you enjoyed it!
I love your videos. They are super helpful! Will you be doing any videos dedicated to MQTT and setting up internet tunnels?
Yep, there will be content on MQTT!
thanks for good info at the right level.
thought about doing a section on antennas and placement?
Sure thing! I do have a video on antennas. I'll link it here. th-cam.com/video/F6w4QtYE6L8/w-d-xo.html
Sure thing! I do have a video on antennas. I'll link it here. th-cam.com/video/F6w4QtYE6L8/w-d-xo.html
Thanks for this video, it's great!
In my T-Deck I used the default LONG_FAST channel and the transmission bandwidth received by my RTL-SDR is 256 kHz. Based on your video I started to wonder if it should not be by default lower for the long range communication?
Sure thing! The developers made Long-Fast the default since it's a good balance of distance and speed. The slower settings really do get congested after the number of nodes grow
Thanks for the video, much better than reading! I would love to learn more about your SDR setup to capture those signals and demonstrate it. Did you use a filter?
Sure thing! Nothing special on the SDR side. The key is changing the LoRa transmitter settings, especially bandwidth.
Thanks for the series! I'm curious, with regard to the hop setting and the default of 3. if a packet or message passes through a node set up as router, does the count get reset? The maximum of 7 hops seems kind of limiting for a network that could theoretically cover a pretty big area.
Sure thing! Devices setup as router/repeater don't reset the hop count. High hop counts really make too much network congestion.
I assume the SX126X RX boosted gain option is also valid for selection on/off when using the newer SX127X?
I'm a Ham interested in LoRa coms. Thinking about getting three radios, 2 in our cars and one connected to a high gain vertical antenna on my ham tower. This should give us good coverage in the local area. But, my Smart home equipment is from YoLink using LoRa. I fear the 915 MHz environment here is going to be too polluted. Every YoLink device has a radio running.
Will a com receiver be De-sensed by my YoLink system?
It should be fine. I have a number of devices on 915MHz like my weather station, soil sensors, ect. No issues so far.
Hi. Which SDR are you using?
Once setup - does the receiver accept only one type of transmission (long-fast)
Or will it listen for all transmission types ?
Settings need to match with the transmitter.
You could experiment with laser comms.
Can you go over adding a private channel, for use on a local mesh?
I've gone to the Channel menu (4th icon from left) and clicked on the name Field, I clicked "Add", entered a channel name, then clicked save. I clicked on Send and it presents me with a QR code.
When I scan the QR code on another device that's connected to the public MQTT server on channel zero, all traffic to/from the MQTT server ceases.
My understanding from the documentation was that traffic on channel zero would always be sent and received and that each node with the same channel 1 (for example) setup could talk to each other. That doesn't happen with me. Once I switch to channel 1, the newly set up private channel, by going to Radio Configuration... Channel... And clicking on the new private channel all traffic ceases.
What am I doing wrong?
Do you have to "switch" channels to send a message on Channel 0 and switch again to Channel 1 (private channel) if you want to send a private message to a node on Channel 1?
How do you start a conversation on the private channel if you've not communicated with that node before?
Hey there, you found an issue I also agree is underdocumented. Until it gets fixed, I can give you a few pointers that should get you unstuck.
When sending a message (and 1 and 2 count with MQTT as well) ALL of the following need to match on both devices:
1. LoRa modem preset: If you added a private channel, this probably changed! Double check that the "LoRa channel" is set to 20 if you are using the default LongFast. It's fine if it's 0 unless you added a private primary channel, then you need to change it back to 20 to work with the public mesh.
2. Channel PSK: You added a private channel, I'm sure you got the PSK right, just needs to match.
3. Channel Name: This is the kicker, over Radio AND MQTT, the encryption (and MQTT topics) use the name of the channel to know which PSK to use on the receiver. If sender and receiver have the same channel PSK but different names, there won't be a message received.
Bonus tip: Direct messages only work if sender and receiver have identical primary channels per above :)
I hope the above can be further documented officially (or improved) soon
My sources are experimentation, and some chats with the devs
[Update:] Maybe this was an MQTT issue, as, after several hours, I started receiving messages without me changing anything!
[Was:]
Thanks for your help. A more important problem has arisen!
I have 3 nodes, one is connected to the public MQTT server, the other two can each talk to each other and i send messages to the MQTT server. All was well until 8 days ago... Then, one message would get sent again, and again, and again, at least once every time I cold booted a node... For more than 8 days! This evening, I reset all nodes to factory settings, deleted the Meshtastic app and cleared it's cache and data prior to reinstalling the app and reconfiguring the nodes. Reconfiguring them is pretty easy... Each of the three nodes sees the traffic coming from the MQTT server, but no messages are being received from the MQTT server. I've quadruple-checked all the settings and don't understand why none of the nodes is receiving messages. When I send messages, they get the checkmark, but no responses come back. Messages sent from the node connected to the MQTT server show an up arrow, not a checkmark. Something is wrong! I'm seeing 28 of 59 nodes connected. So confused! Getting this to work is easy, but when it goes wrong, it's a total pain.
The MQTT node has MQTT and proxy to client enabled. The "LongFast" channel has uplink and downlink enabled and is otherwise at its defaults. The channel settings for the other two nodes are at their defaults.
Any suggestions?
How are you getting the node to constantly TX in order to view it on SDR#? I can see the signal when I TX a message, but I can't seem to get it to constantly TX.
I'm using a very narrow bandwidth (12kHz) in order to see the LoRa signal. I don't believe you can set that in the Meshtastic app, so I'm using some code from RAK Wireless GitHub page and setting the bandwidth there
@@The_Comms_Channel oh. That's pretty cool
Is that hop limit explained correctly? I thought that hop limit refered to how many times a node retransmitted the same data. If the mesh only allows a msg to travel through 3 nodes/3 hops it won't make it very far?
The node with the lowest signal (and likely furthest away) will rebroadcast first to ensure that the hops are reaching as far as they can.
@@The_Comms_Channel I see I think. So if a node knows for a fact that the msg was received it will continue to transmit it to the next node. On and on and on?
does the radio freq.matter?
Yes. All devices need to be on the same frequency (LoRa Channel)
Why is mine on the 928mhz ?
Not sure what you mean. Is your frequency set to that?
What about "audio" ?...no body talks about it,plz can you explain it,it is already in the advanced settings
Audio only works on 2.4GHz and there's only one board that supports it. Not much use for it.
You know what time it is? 😂
Nerd Time! 😂