Meshtastic devices have really taken off in the UK over the last few months and there is now an established Mesh across a large portion of the UK mainland.

Looking to expand the device capability I stumbled across a really interesting little project that is still in the early stages of development but, is functional and worth trying out.

The TC²-BBS Meshtastic Version is a simple BBS system that runs on a RaspberryPi, Linux PC or virtual machine (VM) and can connect to a Meshtastic device via either serial, USB or TCP/IP. Having my M0AWS-1 Meshtastic node at home connected to Wifi I decided to use a TCP/IP connection to the device from a Linux VM running the Python based TC²-BBS Meshtastic BBS.

Following the instructions on how to deploy the BBS is pretty straight forward and it was up and running in no time at all. With a little editing of the code I soon had the Python based BBS software M0AWS branded and connected to my Meshtastic node-1.

The BBS system is very reminiscent of the old packet BBS systems of a bygone era but, it is ideal for the Meshtastic world as the simple menus and user interface are easily transmitted in seconds via the Mesh using minimal bandwidth.

The BBS is accessible by opening a Direct Message session with the M0AWS-1 node. Sending the letter H to the node will get you the initial help screen showing the menu above and then from there onwards it’s just a matter of selecting the menu item and following the BBS prompts to use the BBS.

The BBS also works across MQTT. I tested it with Dave, G4PPN and it worked perfectly via the Meshtastic MQTT server.

This simple but, effective BBS for the Meshtastic network will add a new message store/forward capability to the Mesh and could prove to be very important to the development of the Meshtastic mesh in the UK and the rest of the world.

More soon …

Source

A couple of folks have asked for my configuration files for my LoRa APRS trackers and i-gates, so I thought I would just share them in a follow-up post. Be sure to read my first and second LoRa APRS posts.

Here is my tracker_config.json file:

{
	"beacons": [
		{
			"callsign": "W0RMT-XX",
			"symbol": "[",
			"overlay": "/",
			"micE": "",
			"comment": "",
			"smartBeacon": {
				"active": true,
				"slowRate": 120,
				"slowSpeed": 3,
				"fastRate": 60,
				"fastSpeed": 15,
				"minTxDist": 50,
				"minDeltaBeacon": 20,
				"turnMinDeg": 12,
				"turnSlope": 60
			}			
		},
		{
			"callsign": "W0RMT-XX",
			"symbol": "k",
			"overlay": "/",
			"micE": "",
			"comment": "",
			"smartBeacon": {
				"active": true,
				"slowRate": 120,
				"slowSpeed": 10,
				"fastRate": 60,
				"fastSpeed": 70,
				"minTxDist": 100,
				"minDeltaBeacon": 12,
				"turnMinDeg": 10,
				"turnSlope": 80
			}
		},
		{
			"callsign": "W0RMT-XX",
			"symbol": "b",
			"overlay": "/",
			"micE": "",
			"comment": "",
			"smartBeacon": {
				"active": true,
				"slowRate": 120,
				"slowSpeed": 5,
				"fastRate": 60,
				"fastSpeed": 40,
				"minTxDist": 100,
				"minDeltaBeacon": 12,
				"turnMinDeg": 12,
				"turnSlope": 60
			}
		}
	],
	"display": {
		"showSymbol": true,
		"ecoMode": false,
		"timeout": 4,
		"turn180" : false
    },
	"other": {
		"simplifiedTrackerMode": false,
		"sendCommentAfterXBeacons": 10,
		"path": "WIDE1-1",
		"nonSmartBeaconRate": 15,
		"rememberStationTime": 30,
		"maxDistanceToTracker": 30, 
		"standingUpdateTime": 15,
		"sendAltitude": true,
		"sendBatteryInfo": true,
		"bluetoothType": 1,
		"bluetoothActive": true,
		"disableGPS": false
	},
	"winlink": {
		"password": "ABCDEF"
	},
	"bme": {
		"active": false,
		"sendTelemetry": false,
		"heightCorrection": 0
	},
	"notification": {
		"ledTx": false,
		"ledTxPin": 13,
		"ledMessage": false,
		"ledMessagePin": 2,
		"ledFlashlight": false,
		"ledFlashlightPin": 14,
		"buzzerActive": false,
		"buzzerPinTone": 33,
		"buzzerPinVcc": 25,
		"bootUpBeep": false,
		"txBeep": false,
		"messageRxBeep": false,
		"stationBeep": false,
		"lowBatteryBeep": false,
		"shutDownBeep": false
	},
	"lora": [
		{
			"frequency": 433775000,
			"spreadingFactor": 12,
			"signalBandwidth": 125000,
			"codingRate4": 5,
			"power": 20
		},
		{
			"frequency": 433775000,
			"spreadingFactor": 12,
			"signalBandwidth": 125000,
			"codingRate4": 5,
			"power": 20
		},
		{
			"frequency": 433775000,
			"spreadingFactor": 12,
			"signalBandwidth": 125000,
			"codingRate4": 5,
			"power": 20
		}
	],
	"pttTrigger": {
		"active": false,
		"io_pin": 4,
		"preDelay": 0,
		"postDelay": 0,
		"reverse": false
	}
}

And here is my igate_conf.json file:

{
    "callsign": "W0RMT-XX",
    "wifi": {
        "autoAP": {
            "password": "1234567890",
            "powerOff": 10
        },
        "AP": [
            {
                "ssid": "networkssid",
                "password": "networkpwd"
            }
        ]
    },
    "beacon": {
        "latitude": XX.XXXXXX,
        "longitude": XXX.XXXXXX,
        "comment": "LoRa APRS IGATE",
        "interval": 15,
        "overlay": "L",
        "symbol": "a",
        "path": "WIDE1-1",
        "sendViaAPRSIS": true,
        "sendViaRF": true
    },
    "digi": {
        "mode": 2
    },
    "aprs_is": {
        "active": true,
        "passcode": "XXXX",
        "server": "noam.aprs2.net",
        "port": 14580,
        "filter": "m/50",
        "toRF": true
    },
    "lora": {
        "txFreq": 433775000,
        "rxFreq": 433775000,
        "spreadingFactor": 12,
        "signalBandwidth": 125000,
        "codingRate4": 5,
        "power": 20,
        "txActive": true,
        "rxActive": true
    },
    "display": {
        "alwaysOn": true,
        "timeout": 4,
        "turn180": false
    },
    "syslog": {
        "active": true,
        "server": "logservernamehere",
        "port": XXXXX
    },
    "bme": {
        "active": false
    },
    "ota": {
        "username": "",
        "password": ""
    },
    "other": {
        "rememberStationTime": 30,
        "sendBatteryVoltage": false,
        "externalVoltageMeasurement": false,
        "externalVoltagePin": 34
    }
}

In each case you will need to customize for your callsign and SSID, Winlink pwd, WiFi network, APRS-IS access, lat/lon, etc.

Please comment if you have any questions!

I’ve been experimenting with and using LoRa APRS for a couple of weeks now. Here is the first post I wrote about getting started with it. If you haven’t read that one yet, I suggest you start there. I’ve also been trying to learn a bit more about the LoRa modulation (or “Frequency Shift Chirp Modulation”) protocol.

LoRa Modulation

This video offers a very good introduction to the specifics. It is a bit mathematical, so be prepared for that, but also accessible.

LoRa APRS as implemented in the code by Ricardo CA2RXU uses a spreading factor of 12. If you watched the video you know that this corresponds to a symbol set of 2¹² (4096), or 12 bits/symbol. That is 4096 different chirp waveforms! LoRa uses a pretty interesting method to discern one waveform from another, and therefore decode the corresponding symbol. Watch the video above as the author explains it better than I can.

What I am really interested in knowing is how this modulation technique performs in real-world applications with beaconing positions at low power.

LoRa APRS Practical Use

I’ve been trying to use LoRa APRS in a variety of use cases. I now have i-gates set up at my home and work locations. I am also building a portable LoRa APRS digipeater and/or i-gate that I can deploy as needed to additional coverage. That will be the subject of a future post.

The i-gate in my office (W0RMT-41) in downtown Denver is on the 7th floor of my building against a window facing northeast, and uses one of the small “Hershey’s kiss” 433 MHz mag mount antennas on top of my filing cabinet. I would call it a compromise setup for sure.

I have a tracker in my mobile with a 10W amplifier, and a low-power (100 mW) portable tracker that I use while walking and running. I have re-cased the low power tracker since my last blog post, thanks to AG7U for providing the 3D printed case!

At 10W, my mobile tracker does very well in all of the areas that I drive on a regular basis. I get solid tracks that are much better than those I get using VHF FM APRS and the same smart beaconing settings. Here is a typical track from home to the office, before I installed an i-gate in my office in downtown Denver.

Since installing the i-gate in my office, I also get good coverage for the 100 mW tracker downtown. In this example, you can see where I parked my truck (W0RMT-46), the truck of another local amateur using LoRa APRS (AB0VZ-45), and my walk from the truck to the office (W0RMT-45).

And here is where it gets impressive, I think. I went for a run of about 5 miles from the office and wore the tracker in my running belt with the antenna against my back. I was curious to see if my office i-gate would receive my beacons. Part of this run is actually below the street grade along Cherry Creek, and then things open up a bit more once I get to the Platte River and head south. While there is certainly a bit of wonkiness in the below grade section, I would still consider this a full coverage track. Amazing, I think.

And here is a little 3 mile run from home while wearing the tracker in my running belt, with the terrain at or below the home i-gate. This track has great coverage. Remember- the tracker is only 100 mW!

Finally, I have been pushing the limits of the little 100 mW tracker in terms of power and terrain when running from home. I’ve done a couple of tests wearing the tracker in my belt as described above, and also while wearing it in the front of my running vest/pack.

Here are the tracks from two test runs, one (green track) with the tracker in my belt, and the other (blue track) with the tracker in my vest. The actual route is shown in red, as recorded by my watch.

To be fair, this was challenging for the little tracker as the run goes up on to a mesa above my home digi, and then out across the mesa. So there is no line of sight, and no good reflection surface either (as there is in the city). Here is the profile (out and back).

I’ve got a lot more testing ideas and I am looking forward to plaing with the portable digi/i-gate once I build that.

Isn’t amateur radio a great hobby? There are so many things to pursue and learn about. It’s fun when you open a new door and develop new skills and knowledge.

After having ditched Meshtastic, for now at least, I had a fiddle with two of the LoRa modules with a view to repurposing them. And there they are. The first is a LoRa APRS r/o iGate, listening on 439.9125MHz, and the second is a receiver for radiosondes listening around 400MHz.

Nestled under a 70cm ground plane in the shack is, of course a good way to ensure nothing is ever received unless it is very close! However, it is destined for greater things… although at the end of the day it’s just me fiddling. The LoRa APRS map is at https://lora.ham-radio-op.net/

The radiosonde one stands a better chance of actually receiving something, especially as it is currently connected to the 70cm big wheel antenna in the loft. See https://sondehub.org/

The plan is to connect these two along with the module running TinyGS to a common antenna currently in the loft. They will be connected using a Crosscountry Wireless multicoupler which is due to arrive in a day or so.

A local amateur operator (WB5PJB Gary) reached out to me recenty to see if I wanted to get involved using LoRa APRS on 433 MHz. Gary and I used to talk quit a bit years ago when were experimenting with D-STAR and D-RATS file transfers, but we had never met in person. I had played around with 915 MHz briefly using Meshtastic, and had a few of those boards but never really got into it. So when Gary reached out I though this sounded like a fun thing to dive in to and a good opportunity to meet him in person.

A group of amateurs in the South Metro/Douglas County Colorado area have been using LoRa APRS and setting up a network of i-gates which feed into APRS-IS. They have used this system to support a motorcycle ride in the foothills, and have had a lot of success. Check out the ARESDEC LoRa APRS web page for more details.

LoRa (“Long Range”) is a chirp spread spectrum modulation technique which can be used at low power levels. LoRa “encodes information on radio waves using chirp pulses – similar to the way dolphins and bats communicate! LoRa modulated transmission is robust against disturbances and can be received across great distances.” LoRa generally operates in unlicensed radio spectrum (e.g., 433 MHz, 868 MHz, and 915 MHz). Because LoRA is suited for small data packets that do not need to be transmitted and received at high speeds, it is a good fit for APRS. Using LoRa for tracking locations and feeding into the APRS system requires LoRa i-gates to connect to APRS-IS, hence this project.

Gary and I met along with Art (N0AIU – another north metro amateur operator) to set up some LoRa i-gates and trackers. The i-gate hardware are the LILYGO® LoRa32 433 MHz (version 1.6 through 2.1), and the trackers are LILYGO® T-Beam Meshtastic 433 MHz (soldered OLED version 1.0 through 2.1). These devices get programmed with firmware by Ricardo CA2RXU. He has both i-gate firmware and tracker firmware. These are programmed using VSCODE. Ricardo has good instructions for this on his github repositories. Power output for the boards is set at 20 dBm in the firmware, which corresponds to 100 mW. One can use an external amplifier to boost this up to 1W, 5W, 10W, etc if needed.

Thanks to Gary, I am up and running with the northern-most LoRa APRS i-gate in the Denver metro/Front Range area: W0RMT-40. It seems to be the informal convention of this group and mode to use higher SSIDs to distinguish from VHF APRS stations.

I’ve also got one low powered (100 mW) tracker (W0RMT-45) to mess around with, and a higher-powered (10W) tracker to experiment with as well.

I’m looking forward to using this system and experimenting a bit. I am impressed that my i-gate is receiving and decoding beacons from a low-power i-gate over 47 miles away at -123 dBm / -9.75 dB! Below is a profile for the line from a mobile tracker I received that is 34 miles away. It’s an advantageous line of sight for the mobile, but still an impressive reception and decode for a lower power tracker.

And finally, here is a quick test of the 100 mW tracker on the dash on my truck while making a short local round trip. It is amazing what such low power can do.

Next steps will be to install a tracker in my truck, and use another tracker in a smaller case (the Pelican case is temporary) while I am hiking and running.

If you were to ask a member of the public about the subject of 'radio', they'll probably answer that it was some old technology that existed in the past and is now nearly dead. The reality is that it's hiding in plain sight. 

Think WiFi, Bluetooth, mobile phones, Satellite TV, Starlink, parking sensors, etc, we're surrounded by 'radio' technology. It's just that 'radio' has evolved and is increasingly in a digital format.

More and more devices now have microprocessors embedded and they are communicating with other devices using the concept of the 'internet of things'. One of the systems for doing this is LoRa (Long Range Low Power).

This concept has been developed so that radio signals from experimental satellites in low earth orbit can be received by hobbyists all around the world and then the data is fed back by the internet to the control station. One of the frequencies used for this is at 433 MHz in the radio amateur 70cms band.

TinyGS is one such network and is described as follows... "TinyGS is an open network of Ground Stations distributed around the world to receive and operate LoRa satellites, weather probes and other flying objects, using cheap and versatile modules."

Jeffrey, EI7IRB recently gave a presentation titled "TinyGS, the Open Source Global Satellite Network" to the Mid-Ulster Amateur Radio Club and they now have it up on their YouTube channel.

The video starts at about 7 mins, you can skip back to the start of you want to watch the introduction.

This Meshtastic business seems often very hit and miss. Locally there is an expectation that it will always work and if you can hit one node one day you should always be able to. Or at least that’s what I glean from comments. Of course, just a few mW at 868MHz is not destined for long distance comms, and yet I can get 24 miles provided the path is line of sight. Not bad. But I can’t manage 1.3km to my nearest neighbour who can get out all over the place. There is a hill to consider there, plus many houses, so not surprising really. Oh yes, and there is the small matter of the antenna still being in the loft so it has to punch through wood and concrete, often wet at that, before it gets to air.

For now, at least locally traffic is mostly messages asking if one can be heard.

There is a series side of course. Nodes can be placed in advantageous positions, run off battery and solar recharged, and left as area repeaters (or routers in Meshtastic parlance) forming a mesh with other similarly advantageously placed nodes. We have this locally to some extent. It is very easy then to get into a position where you a reach those nodes, just don’t expect it to work from your basement. Used correctly – and that probably means used as originally proposed – it is certainly neat, potentially ubiquitous, even anonymous. I already have a use for it at ‘work’ where I need data comms across 3km with no line of sight and with little or no money available…

For now, we’re all playing and having fun or getting frustrated. The worry is people will give up and lack of coordination will make that worse.

Of course, it’s early days, the software is still being developed, the boards are hard to come by but that will change as stock moves. It’s quite interesting to be in this now, relatively early on and as it develops further.

The Heltec ESP32 v3 LORA devices have a coil type Bluetooth/Wifi antenna on the PCB from the factory. This antenna doesn’t work particularly well and has very limited range so, I decided to do something about it.

Getting out the calculator a quarter wave at 2400Mhz is 29.7mm. Looking at the coil antenna on the PCB I decided the best way to connect the new antenna would be to solder it to the coil of the existing antenna. This would short out the coil completely whilst creating a solid mount point for the new antenna.

After a little measuring I decided to use a 31mm long piece of 1.5mm hard core mains cable for the new antenna. I stripped back the insulation from one end of the wire so that the exposed copper wire was exactly the length to short across all the windings of the coil antenna on the PCB.

Attaching the the wire to the coil was easy enough to do but, it’s worth pointing out that you need to be quick so that the heat doesn’t transfer down onto the PCB desoldering the coil antenna from the device.

Whilst tinkering with the Bluetooth antenna I decided I would also make a neat little quarter wave 868Mhz vertical antenna for this device whilst I had it all apart. This is my Meshtastic node-2 and it’s sole purpose is to allow me to use my iPad to send/receive messages via bluetooth which are then forwarded on to my base node-1 in the house. Node-1 is connected to the house wifi and the Meshtastic MQTT server. This combination allows me to message people on the mesh even though there are no local nodes within RF range.

Running the numbers for the 868Mhz antenna the vertical will need to be around 82.1mm long with a radial of similar length. I had to hand a very nice SMA to N Type chassis mount socket that would be ideal to mount the antenna to the case. I drilled out the holes in the case, measured out the wires and attached it all to the case. Connecting the antenna to the N Type socket I connected my VNA and set about tuning the antenna to resonance.

Squeezing the radial and SMA connector into the case I realised I really could do with a 90 degree SMA connector so, I quickly ordered one from Amazon which will be delivered tomorrow. Connecting up my VNA, I had to trim the antenna down to get it to resonance. The SWR ended up at 1.2:1 which is ideal. I ended up cutting off more wire than I thought I would to get the antenna to resonance but, this is due to the extra capacitance caused by the insulation on the wire. If I had used bare copper wire then I wouldn’t of had to cut so much off. I eventually ended up with around 72.9mm of wire for both the antenna and radial.

Putting the device back into the case and connecting the USB battery the device fired up and immediately connected to my node in the house. Checking the signal strength of node-1 in the house I could see a 7dB increase in signal strength compared to the little wire antenna that comes with the device. This is a significant improvement for such a simple antenna and well worth the effort.

Next I had to drill a hole in the front of the Heltec case so that the Bluetooth antenna could poke out the front and be bent up vertically. This worked out really well and improved the Bluetooth range massively.

Putting the node back in the house and taking my iPad down to the end of the garden some 30m away I could instantly connect to the device via Bluetooth from my iPad, something I’d not been able to do prior to adding the new antennas. I can now use the Heltec device via Bluetooth from anywhere in the house or garden making it much more accessible.

It’s amazing the difference an hour and two little pieces of wire can make to these devices and is well worth the effort.

More soon …

In the latest video on the Tech Minds YouTube channel Matt tests out the Meshtastic software running on varius Lilygo LoRa devices. Meshtastic is software that can run on cheap LoRa hardware that enables off-grid mesh network based communications.

Being mesh network based means that there are no central repeaters, and instead each device can extend the range of the network by being a repeater itself. Meshtastic can run on various cheap 'Lilygo' branded LoRa devices that come in 433, 868 or 915 MHz license free frequencies depending on your regional band plan.

In his video Matt tests out various models in the Lilygo range, including a ESP32 based wrist watch and he also shows how to install the firmware on each using the online flasher.

Meshtastic is a relatively new thing in the internet of things (IOT) world and is gaining traction in the U.K. at the moment.

So what is Meshtastic?

Meshtastic is an open source, off-grid, decentralised mesh network built to run on affordable, low-power devices on the 868Mhz industrial, scientific, and medical (ISM) band. (Some devices can also run on the 433Mhz 70cm HAM band.)

The ISM band is licence free but, has limits on the RF power levels that can be used. The one plus over the HAM bands is that you can legally transfer encrypted messages over the ISM band making it secure.

The best way to think of Meshtastic is a radio version of the online decentralised Matrix chat system but, without the large server requirements and ever growing database!

There are quite a few Meshtastic compatible devices on the market today with many costing around the £20 mark whilst others like the LillyGo T-Echo costing over £100 in the U.K. even though they are less than half the price in the USA.

Since I’m just starting out on my Meshtastic adventure I thought I’d start with a pair of Heltec ESP32 v3 devices that are normally readily available on Amazon but, due to the current push to build a U.K. wide mesh, they are currently out of stock pretty much everywhere.

Loading the Meshtastic firmware onto the devices is fairly straight forward and can be done using the web installer via either the Edge or Chromium web browsers.
(Note: If using Windows O/S you will need to install some drivers from the Meshtastic website to be able to communicate with the devices)

Having neither of the two browsers and being a Linux command line junkie I decided to use the Python programme to load the firmware onto the two devices. It’s worth noting that you don’t need any drivers to be able to communicate with the devices if you’re using either Debian or one of the many Ubuntu flavours of Linux O/S.

Using the Python command line program sounds like a more complicated approach but, in reality it’s super simple, extremely reliable, quick and if like me you use a Linux PC in the radio shack then you most likely already have most of what you need to get the job done. Just follow the simple steps as laid out on the Meshtastic web site and you’ll have the firmware loaded in no time at all.

The firmware takes less than a minute to copy across to the Heltec device and is automatically rebooted ready for configuration once the transfer has completed.

It is possible to configure the device via the command line tool however, since there is a nice GUI app for both Apple iOS and Android devices I decided to install the Meshtastic app on my iPad and connect to the device via Bluetooth to configure it.

Once you’ve got the Meshtastic app installed on your device and have connected via Bluetooth you’ll be ready to start configuring the device to join the mesh. The first thing you want to do is set the region. This is different in each country but, in the UK we use the EU_868 region settings. This will set the device to use the 868Mhz ISM band which is the band being used to build the U.K. wide mesh.

There is a multitude of configuration options within the app which I will go into in greater detail in a series of articles at a later date.

For those of you that, like me aren’t near any other nodes you can connect the devices to the internet and use the Meshtastic MQTT server to communicate with other nodes. This of course isn’t off-grid but, it will get you started until the mesh grows into your local area at which point your device will automatically start communicating with the other nodes over radio.

Once you are connected to either the MQTT server or other nodes via radio you will see the other node details appear in the Meshtastic app. It’s interesting to look at the information and see signal strengths and traffic levels etc for each node.

There are a multitude of cases available for the Heltec v3 devices, especially if you have access to a 3D printer. One of the nicest cases I have seen is the Bender from IKB3D (I know, it’s a strange name!) but, it really is a super little case for the Heltec series of devices.

You can either buy the 3D print files for £8.99 and print it yourself or just order a pre-printed and assembled case directly from the website although, due to demand there is a long lead time currently.

More soon …