In the past few years we’ve seen the rise of low-power mesh networking devices for everything from IoT devices, weather stations, and even off-grid communications networks. These radio modules are largely exempt from licensing requirements due to their low power and typically only operate within a very small area. But by borrowing some ideas from the licensed side of amateur radio, [Peter Fairlie] built this Meshtastic repeater which can greatly extend the range of his low-power system.
[Peter] is calling this a “long lines relay” after old AT&T microwave technology, but it is essentially two Heltec modules set up to operate as Meshtastic nodes, where one can operate as a receiver while the other re-transmits the received signal. Each is connected to a log-periodic antenna to greatly increase the range of the repeater along the direction of the antenna. These antennas are highly directional, but they allow [Peter] to connect to Meshtastic networks in the semi-distant city of Toronto which he otherwise wouldn’t be able to hear.
With the two modules connected to the antennas and enclosed in a weatherproof box, the system was mounted on a radio tower allowing a greatly increased range for these low-power devices. If you’re familiar with LoRa but not Meshtastic, it’s become somewhat popular lately for being a straightforward tool for setting up low-power networks for various tasks. [Jonathan Bennett] explored it in much more detail as an emergency communications mode after a tornado hit his home town.
Local codes may be different, but it isn’t uncommon that power limits for unlicensed radio devices refer to e.r.p. (effective radiated power) rather than the transmitter power. This makes using directional antennae less effective (at best, because it requires transmitter output power to be limited) or illegal (at worst). Know, what you are doing.
There are different rules for fixed backhaul links too
Good thing the FCC has no enforcement officers and they can’t hardly enforce real issues much less these matters.
Yes, no FCC in Canada but there is an equivalent agency. Enforcement in both countries tends to be driven by complaints.
The FCC has not enforced anything(outside of TV/FM/Pub.safety) in
30 years. If someone is making ALOT of money from it the FCC
could care less. Real shame… :(
Edit: If someone IS NOT making money.
Will we EVER get a “Edit” feature????
It’s generally not a good idea to leave those cheap OLED displays running all the time. They’ll wear out in a year.
Ask me how I know.
They auto shut-off after like 15 min.
How you know ?
The default settings of the Meshtastic firmware turns off the display after 10 minutes.
they dont run all the time.. they default to turn off after 10 min
What’s the range?
“These radio modules are largely exempt from licensing requirements due to their low power”
Bad joke.
I seem to be missing something; how are these a repeater unit?
Are these two transceivers Bluetooth linked together to share the payloads?
Is [Peter] just expecting RF to leak from the first unit to the second (clearly the directional antenna isn’t perfect)?
Meshtastic nodes are not linked trough BT. They are designed to repeat messages on the same frequency (902 -928 MHz) until the message hop count is exhausted.
(https://meshtastic.org/docs/configuration/radio/lora/#max-hops)
But how do the 2 units talk to one another to hand off the messages for re-broadcast?
LPDA for a fixed frequency narrow band signal…. I guess use what you have.
Use a log-per antenna for a single frequency band. He could have had so much more gain in the same volume.
I too have seen a range of YT videos in the sidebar mentioning ‘meshtastic’.
And all I could think was how much that word irks me.
Not sure why but I do so dislike it.
LANtastic was a notorious PO(steaming)S networking package, many years ago.
I’m sure there are other examples of terrible ‘tastic’ products. Can any body think of a ‘tastic’ that didn’t suck? I’m drawing a blank.