Anzio Catterick repeater to be commissioned in the coming weeks

The first main repeater of the Richmondshire Mesh, Anzio Catterick, is expected to be commissioned in the next couple of weeks, an order will be placed with zerofox3D for the Hermes enclosure, a solar panel and some 18650 cells plus a charger for these will be ordered from Amazon at around the same time, as a temporary measure the antenna on the repeater will be the Paradar indoor antenna I currently have until a proper outdoor one can be obtained later, the solar panel will be for charging, the 18650s are for overnight operation.

As the repeater is based on RAKWireless WisBlock hardware then current consumption is expected to be low and the batteries are expected to last without the repeater ever powering down, it can also be OTA updated via Bluetooth as required (the BLE antenna will be installed on the repeater for this purpose).

Anzio Catterick is to be located at my home address and should in theory cover from the far side of the Allenby Road estate to the Richmondshire Walk shopping area, I will be taking out the spectrum analyser with an 868MHz antenna fitted and one of my companion radios to run tests, of course this all depends on where I mount the repeater and ultimately how high up it is and also what antenna is on it at the time.

Once this is commissioned I can then set to work on building the next repeater I want to deploy which will be CRDARS Hudswell, using identical hardware to Anzio Catterick and should in theory cover a link over to Richmond and potentially being at a higher location fill in some gaps that Anzio Catterick can't manage to do.

So lets get this mesh built

further unexpected experiment

Having now got the RAK Wisblock (RAK4631 on RAK19007 base) for use in the Anzio Catterick repeater and a battery I need to work on to change the connector to make it compatible with the Heltec Wireless Tracker I decided to plug that battery into the Wisblock (after repinning it to make the polarity correct) and topping up its charge before beginning the process of discharging it until the protection board kicked in (the battery is a EEMB 3.7V 2000mAh LP10454 flat battery), the battery as of this morning only hit 80% charged, meaning the discharge is generally quite low.

This suggests the RAK4631, because it uses the nRF52840 instead of the ESP32 most likely, is exceptionally efficient, the base board has LEDs on it but all these are turned off while the board is configured as MeshCore repeater (except the charge LED when the battery is charging which is controlled by a TP4054 charge controller), RAK themselves suggest that in transmit it draws at most 125mA, maybe a little more and when it is in sleep mode it is measured in microamps, in other words almost nothing and 17mA on receive (this is without the Bluetooth as we don't use the Bluetooth radio in these in normal operation for MeshCore repeaters).

The batteries I want to use are quoted as being 3400mAh each and these will be in parallel, in electronics when batteries are connected in parallel the current capacity adds up, a good example of connecting batteries in parallel is jump starting a car, this means that if these cells are indeed as advertised this could give a run time where the repeater once constructed will be able to run off the batteries at night and solar during the day all year round, exactly how we want the mesh to function, the batteries should total 3.7V at 13,400mAh if these cells are indeed as advertised, the runtime will also depend on traffic going through the repeater, but I've not heard of anyone having a repeater go down yet because of battery issues other than end of useful life.

The solar panel I'll be specifying for the repeater is rated 6 Watts but I suspect that is in full sun, something rare in the UK but modern panels are getting efficient due to the fact people want to use them more and more for silly reasons, small off-grid projects like these benefit from it massively, so if the unintended and unexpected experiment is to be believed then I don't see any repeaters on this mesh if built using RAK Wisblock hardware to really go down due to the batteries running out

Experiments carried out

In preparation to fully begin deployment of the mesh I've been out doing some experiments, the first experiment was ping testing to my test repeater, these proved successful to the point I've now purchased a Heltec Wireless Tracker (it's like a V3 but it has GNSS on board (I don't simply refer to that as GPS as it receives more than the GPS satellites), I flashed MeshCore to this and left it at home in a bit of an awkward place as it's not cased (inside a mug) and did some private message testing and all the messages sent from the test node (a Heltec V3) made it back to the Wireless Tracker without having to rely on the repeater at any point, though there were a couple of times I thought it might need the repeater, the test repeater is based on a Raspberry Pi Pico using a Paradar indoor antenna, the test node and the Wireless Tracker both use a DIYMalls 868MHz antenna from Amazon (these were a pack of 4 with some pigtails), these are slightly smaller than the Paradar antenna.

With this in mind I am keen to get the mesh deployed over the course of the summer months, the RAK Wisblock on order should be here next week or the week after, all being well, and work can begin to construct that repeater AND get it on the air.

I've also looked at the datasheet for the SX1262 LoRa chip used in many of thesse devices, particularly the receive sensitivity and also put that through the Radio Mobile coverage plotting program with some temporary figures for mast heights and antenna gain, the results look promising but in practice they could vastly differ.

So let us get this mesh up and running as soon as possible

Construction of the mesh is about to begin

So after my initial tests with the test repeater and still seeing no activity on either meshing system beyond what I was doing, the construction of the mesh is about to begin, the first RAKWireless Wisblock (RAK4651 paired to RAK19003 or RAK19007) for use as a repeater has been ordered, now I recommend these for repeater building as current draw is very low because these utilise the Nordic nRF52840 rather than the ESP32 found in most companion devices, this is important because these repeaters will run on batteries and be charged from a solar panel keeping the mesh going when the power goes off, which is the point here as we want it to be as totally off-grid as possible.

The RAK Wisblock on order is the foundation for the Anzio Catterick repeater, this Wisblock will be fitted to a solar panel and a case (zerofox3D Hermes has been chosen for this but as yet not ordered) next month, at this point it is hoped I can install the antenna and put the repeater up on the air.

The antenna will be an outdoor rated antenna, most likely a Paradar antenna, this will have some gain on it which in LoRa applications due to the very low power levels used by transmitters (around 155mW) helps a lot, height also does help and while I am in a top floor flat the higher I can get the antenna the better, this I can work out when I come to deploy the repeater.

I also have a companion device arriving on the day of writing this, the Heltec Wireless Tracker, while this has a build-in GNSS it does not mean that this feature will work with MeshCore, which the Richmondshire Mesh will be using due to it only transmitting as needed and doesn't spit out constant telemetry and not all devices repeat so the mesh is less likely to become congested and messages, which is the whole point, do not fail to reach their destination.

Now is a good time to get companion devices ready and you can also start putting repeaters on air yourself if you would like to do this, if you have an old Heltec V3 lying around in a drawer why not put Meshcore onto it, the firmware is on the Meshcore website for all supported devices and the Meshcore app is in the usual app stores.

Welcome

Welcome to the website of the Richmondshire Mesh, a MeshCore based off-grid mesh messaging network, here you can see what's going on with regards to the mesh and also find out how you can get involved with the mesh, there's plenty of content coming and as the network grows.

You don't need a mobile phone signal or the Internet to use the mesh, all you need is a small radio device paired with an app on your phone (or any phone, even one without a SIM), or a standalone device which are readily available, and if you want to add to the mesh coverage area you can put on a repeater to extend the mesh coverage, the more repeaters there are on the mesh the further it will cover.