I'm probably wrong, but my understanding is that LoRa takes advantage of the spread spectrum between 902 - 928Mhz. You can set a channel offset to adjust the center frequency, but the default would be 0 and starts near the 902 end. For my purposes, I'm using the Very Long Slow channel with an channel offset of 210, which gives me a center frequency landing around 918 or so. The number of "channels" you setup in Meshtastic will increase in frequency accordingly. For my purposes I've setup a "private" mesh network and don't want to compete with other generic LoRa devices. Also after diving into this head first I've learned that resonance and capacitance chance with antenna position and plastic shielding. Your workspace looks awesome!
Ha! This work space is a mess and a reflection of how my brain works. I also figured it was a wide enough spectrum that 915 would be the middle and then the firmware would move around in that space. While the LoRa transmit pattern is spread spectrum, it’s not multiple MHz wide. Watching the nodes around my place communicate for a few hours with an SDR, it became obvious that the default ‘channel’ it’s using life’s for RX/TX at 906.875. I also moved the channel on a device and landed at 912mhz. Why a time to be alive with all these cool tools and options. Hope you can share what you’re using LoRa for. Godspeed
@@JuliansRandomProjectI’m setting up a LoRA / MQTT network in a somewhat remote mountain community for the purpose of SCADA alarms. We often loose power / cellular service in winter storms. I’ve jumped head first down the rabbit hole and purchased a Nano VNA, TinySA ultra and just recently a SDR software defined radio to observe communications and noise floors. Absolutely wild.
The frequency used depends on the slot chosen, I'm using the defaults. I used an SDR to figure out what frequency it was using (it's documented too). I'd built some antennas that worked well, but for remote nodes I use commercial antennas since they're more resistant to weather and vandalism.
Australia and New Zealand have LongFast on 919.875MHz. The other presets are mostly between 915 - 920MHz (except medium fast and medium slow are 926Mhz and 927Mhz)
Great info! Thanks. Is there a term we can search for in the Meshtastic code to find the freqs used per setting/channel? I’ll grep for medium slow and the others to see if I find anything.
I eould recommend not having such high Q antennas. You want an antenna that is a bit more wideband and has swr less than 2. As you move around, change orientation, weather, etc your antenna resonance can change. If you have a very narrow bandwidth, it can get bad fast. There is a reason meshtastic has the testing report section. I recommend you use it.
You can check your exact frequency in the Meshtastic app, in Radio Configuration under LoRa, it's listed as Override Frequency. In the EU this is 869.525MHz rather than the more rounded figure of 868 that you hear mentioned.
Hey. The plastic cover changes the _velocity factor_ of the wire. So if you have a bare wire, it will appear electrically longer with the plastic over it It’s not so much any conductive material, more a dialectic effect that slows down the wave propagation along the wire, making the wire appear longer. Same effect you get with Coax cable. Hope that makes sense Keep experimenting, you’ll discover and learn so much Cheers :-)
Velocity factor, I’m aware of it but not enough to teach others just yet 😊. Same goes for the heat shrink on internal antennas. I’ve got them to tune by just removing some amount of the heat shrink. Thanks!
@@JuliansRandomProject cheers Got 2 more little V3 boards with antenna and case. Already had one. The second unit took less than 10 mins and I was on the air. Foolishly I only purchased one to start with. Couldn’t see anyone via LoRa I now have that on an antenna that was originally supplied with an old PSTN cellular gateway and had a nice dip at 915MHz without doing anything. I can pick up a couple of nodes that are local to me, but once I set it as a router with MQTT set up for our region’s topic, everything started coming through. Once I had the second unit on the air. It could see the first device along with all its MQTT peers Very impressed. Keen to see how many _furthers_ I can get out of the router unit with an antenna with some gain, located at a decent height
Sounds to me that you would need some Local HAM Radio operators to get on board .. Or get a Amateur Radio License.. So you can set up some Higher Power Repeater Nodes in the 33 cm Band (5 Watts) at least ... This system is a Low Power (No Licence) needed.. And similar to Packet or RTTY. Digital Communication Modes. (1/10th of a Watt) AKA 100 Mili-Watts (Won't get much range) think of the potential with Towers and Higher Power. 73s
@@x_CrossHair_x when using my ham license I have to turn off encryption. I’m only interested in Meshtastic to talk to non-licensed folks in a secure manor :)
Nice logo, NSDQ. You are 100% correct above the actual frequency for LoRa Radios. Outside the LoRa Radio world it is common to refer to radio by the "center" of the radio frequencies they use.
Ah yes seen somewhere when messing with python cli that the device was at 906. And was confused. Forgot about that. Spent a day or two on my rtl sdr/HT/flipper looking for signals between 910-930 mhz confused then bam 906ish found em a finally.
But did it work better, after you trimmed the antenna? As I have heard some of the antennas are not even close to the bandwidth needed for the frequency allocation. Good on you for making it work for your situation. 👍
I think he’s right that they trim them between two marks on the workbench or something cause I measured a whole heap of antennas that have come with wireless gear and only two were on the nose, the rest were miles off. Your antenna could be 50mhz plus off resonance. Anyhow, hope yours aren’t but it seems every day at their antenna plants is a Friday 😉
sooo im new to the whole meshtastic thing and i admit im still learning all of it but US "default " public long-fast freq is supposed to be 915mhz.... i have 3 devices and ive been messing around to find out that by default out of the box the override setting is always set to 906 for some reason... and when i set 1 device to default out of box 906, 1 device to 906.875, another to the 915 us default public channel.... none of then see each other let alone communicate with each other... sooo this might be good for private settings but if u have intentions of talking to others publicly on the default us channel it dont work...
Now with that Knowledge (Of the correct Frequency) Build a Coaxial Collinear Antenna (8 Segment At least) .. Don't forget the Velocity Factor of the Coax you use when Trimming the Segments. (With the Aid of your VNA) should help alot.. (Nice Discovery) for Peek Performance and Efficency. 👍👍
@@JuliansRandomProject The device the antenna is used at, e.g. t-beam, t-echo. Remember: 1/4 wave is just a half of the dipole, so it uses the device and/or human (if you hold it) as another half, so its performance will depend on the device it is used with.
@@sofia-p7d4tCorrect. In this example I’m testing with the 3D printed enclosure that I’ll be using the antenna with and the exact length of coax from ipex to female SMA. I even when as far as buying a little ipex to make adapter for the VNA. This is the Device Under Test. I won’t be moving it to another enclosure or different ground plane without testing and adjusting again. Thanks for the feedback!
I'm probably wrong, but my understanding is that LoRa takes advantage of the spread spectrum between 902 - 928Mhz. You can set a channel offset to adjust the center frequency, but the default would be 0 and starts near the 902 end. For my purposes, I'm using the Very Long Slow channel with an channel offset of 210, which gives me a center frequency landing around 918 or so. The number of "channels" you setup in Meshtastic will increase in frequency accordingly. For my purposes I've setup a "private" mesh network and don't want to compete with other generic LoRa devices. Also after diving into this head first I've learned that resonance and capacitance chance with antenna position and plastic shielding. Your workspace looks awesome!
Ha! This work space is a mess and a reflection of how my brain works. I also figured it was a wide enough spectrum that 915 would be the middle and then the firmware would move around in that space. While the LoRa transmit pattern is spread spectrum, it’s not multiple MHz wide. Watching the nodes around my place communicate for a few hours with an SDR, it became obvious that the default ‘channel’ it’s using life’s for RX/TX at 906.875. I also moved the channel on a device and landed at 912mhz. Why a time to be alive with all these cool tools and options. Hope you can share what you’re using LoRa for. Godspeed
@@JuliansRandomProjectI’m setting up a LoRA / MQTT network in a somewhat remote mountain community for the purpose of SCADA alarms. We often loose power / cellular service in winter storms. I’ve jumped head first down the rabbit hole and purchased a Nano VNA, TinySA ultra and just recently a SDR software defined radio to observe communications and noise floors. Absolutely wild.
@@nathanmatthews8172You are a nerds nerd!
The frequency used depends on the slot chosen, I'm using the defaults. I used an SDR to figure out what frequency it was using (it's documented too). I'd built some antennas that worked well, but for remote nodes I use commercial antennas since they're more resistant to weather and vandalism.
Australia and New Zealand have LongFast on 919.875MHz. The other presets are mostly between 915 - 920MHz (except medium fast and medium slow are 926Mhz and 927Mhz)
Great info! Thanks. Is there a term we can search for in the Meshtastic code to find the freqs used per setting/channel? I’ll grep for medium slow and the others to see if I find anything.
I eould recommend not having such high Q antennas. You want an antenna that is a bit more wideband and has swr less than 2.
As you move around, change orientation, weather, etc your antenna resonance can change. If you have a very narrow bandwidth, it can get bad fast.
There is a reason meshtastic has the testing report section. I recommend you use it.
Thanks for the information here. I have been scanning trying to find the frequency and this is exactly what I was looking for.
You can check your exact frequency in the Meshtastic app, in Radio Configuration under LoRa, it's listed as Override Frequency. In the EU this is 869.525MHz rather than the more rounded figure of 868 that you hear mentioned.
Hey. The plastic cover changes the _velocity factor_ of the wire. So if you have a bare wire, it will appear electrically longer with the plastic over it
It’s not so much any conductive material, more a dialectic effect that slows down the wave propagation along the wire, making the wire appear longer.
Same effect you get with Coax cable.
Hope that makes sense
Keep experimenting, you’ll discover and learn so much
Cheers
:-)
Velocity factor, I’m aware of it but not enough to teach others just yet 😊. Same goes for the heat shrink on internal antennas. I’ve got them to tune by just removing some amount of the heat shrink. Thanks!
@@JuliansRandomProject cheers
Got 2 more little V3 boards with antenna and case. Already had one. The second unit took less than 10 mins and I was on the air.
Foolishly I only purchased one to start with. Couldn’t see anyone via LoRa
I now have that on an antenna that was originally supplied with an old PSTN cellular gateway and had a nice dip at 915MHz without doing anything.
I can pick up a couple of nodes that are local to me, but once I set it as a router with MQTT set up for our region’s topic, everything started coming through.
Once I had the second unit on the air. It could see the first device along with all its MQTT peers
Very impressed.
Keen to see how many _furthers_ I can get out of the router unit with an antenna with some gain, located at a decent height
Sounds to me that you would need some Local HAM Radio operators to get on board .. Or get a Amateur Radio License.. So you can set up some Higher Power Repeater Nodes in the 33 cm Band (5 Watts) at least ... This system is a Low Power (No Licence) needed.. And similar to Packet or RTTY. Digital Communication Modes. (1/10th of a Watt) AKA 100 Mili-Watts (Won't get much range) think of the potential with Towers and Higher Power. 73s
@@x_CrossHair_x when using my ham license I have to turn off encryption. I’m only interested in Meshtastic to talk to non-licensed folks in a secure manor :)
watched from Bryan,tx...
Starting Meshtastic in 1 week...
Nice logo, NSDQ. You are 100% correct above the actual frequency for LoRa Radios. Outside the LoRa Radio world it is common to refer to radio by the "center" of the radio frequencies they use.
NSDQ!
You figured out the recipe of the secret sauce!
Ah yes seen somewhere when messing with python cli that the device was at 906. And was confused.
Forgot about that.
Spent a day or two on my rtl sdr/HT/flipper looking for signals between 910-930 mhz confused then bam 906ish found em a finally.
But did it work better, after you trimmed the antenna?
As I have heard some of the antennas are not even close to the bandwidth needed for the frequency allocation.
Good on you for making it work for your situation. 👍
I think he’s right that they trim them between two marks on the workbench or something cause I measured a whole heap of antennas that have come with wireless gear and only two were on the nose, the rest were miles off. Your antenna could be 50mhz plus off resonance. Anyhow, hope yours aren’t but it seems every day at their antenna plants is a Friday 😉
Yes. Got 3 more miles out of it with this single change.
Hi, can you link to the IPEX to SMA cap you are using? Thanks...
I'm using the iPEX to SMA adapters that came in this multi pack amzn.to/3vuulj6
sooo im new to the whole meshtastic thing and i admit im still learning all of it but US "default " public long-fast freq is supposed to be 915mhz.... i have 3 devices and ive been messing around to find out that by default out of the box the override setting is always set to 906 for some reason... and when i set 1 device to default out of box 906, 1 device to 906.875, another to the 915 us default public channel.... none of then see each other let alone communicate with each other... sooo this might be good for private settings but if u have intentions of talking to others publicly on the default us channel it dont work...
You might find the about page for my local mesh helpful. www.austinmesh.org/learn/#about
Is that a Nintendo DS stylus?
Yep :)
Yup, I was struggling with materials changing SWR. Is this the same Julian I met in Belton last weekend?
Velocity factor in effect with materials. If he was handsome... yes, same guy.
Which case is that?
Simon Muzi’s H1 case for the heltec board. makerworld.com/en/models/160873#profileId-229552
@@JuliansRandomProject Thank you!
How is the cover removed from the antenna, without breaking it?
Pull and wiggle.
Same question! Im pulling and wiggling with no luck.
Try a little heat. That worked for me!
Pair of pliers and some balls and I got her loose. Thanks 🎉
I purchased 4 devices and all 4 have died. Had them 2 weeks. They all died and YES I put batteries in After the antenna, JUNK!
Which model did you purchase and from where? I hear good things about the RAK wireless boards but haven’t bought them yet
Now with that Knowledge (Of the correct Frequency) Build a Coaxial Collinear Antenna (8 Segment At least) .. Don't forget the Velocity Factor of the Coax you use when Trimming the Segments. (With the Aid of your VNA) should help alot.. (Nice Discovery) for Peek Performance and Efficency. 👍👍
Another mistake you're making is tuning it for the wrong DUT.
DUT? Device Under Test?
@@JuliansRandomProject yes
@@sofia-p7d4t what would be the correct DUT? I feel like I’m missing something :)
@@JuliansRandomProject The device the antenna is used at, e.g. t-beam, t-echo. Remember: 1/4 wave is just a half of the dipole, so it uses the device and/or human (if you hold it) as another half, so its performance will depend on the device it is used with.
@@sofia-p7d4tCorrect. In this example I’m testing with the 3D printed enclosure that I’ll be using the antenna with and the exact length of coax from ipex to female SMA. I even when as far as buying a little ipex to make adapter for the VNA. This is the Device Under Test. I won’t be moving it to another enclosure or different ground plane without testing and adjusting again. Thanks for the feedback!
So much wrong in this video. Please learn more.
Are you ok?