Random Connections of the Meshcore World

I've never claimed to be an electronics person and, though I always try to pick things up as I go along, I'm still, and always will be, a learner.

That, however, doesn't mean I can't ask questions that get to the heart of the matter. And this is what I've been up to this week. And it seems a lot of people don't have the answers, seemingly because they've been connecting things up without much thought as to maximum voltages and potential longer-term damage to their Mesh boards.

First, let's remember that there are two main types of Meshcore (or Meshtastic, if you prefer that) board: Heltek, now at v4, and the more expensive but often preferred RAK boards. With both Heltek and RAK boards now being optimised for low current draw, one can conclude there is little to choose between them. The only board I've had software, rather than hardware issues, is in fact the RAK board (a database locked error, requiring a re-flashing).

The solar charging of these two boards are not the same. The Heltek v4 has integrated MPPT charging, whereas the RAK boards do not.

Many folk use the external MPPT charging board shown below. It costs around £10 and, in my case, is rated for 12V solar panels, with 5V output. 

MPPT charge regulator. Fine for RAK boards, no good for Heltek.

My real-world test of this board shows it is entirely successful with the RAK boards. You connect any solar panel, of any rating between 6 and 24V, to the 'SOLAR IN' socket. The output goes to the input of the RAK board. Your battery connects to the remaining board socket. Battery charging begins when the MPPT regulator sees about 3.7V. It will only ever provide around 4.2V in full sunshine, which is exactly what we need. The RAK board has a 'never exceed' input limit of 5.5V. 

My test so far this spring shows that the battery is charged up to around 80-81% and only discharges by around 1% overnight. In winter, the charge and discharge will of course suffer more, but we'll cross that bridge once winter arrives; we have summer to enjoy first!

When it comes to the Heltek V4, MPPT is already on-board and you can't therefore connect an external regulator in series, because the battery will see little or even no charging. The trouble with the Heltek is that you need to provide the correct input voltage (not more than around 6V), without going through an MPPT regulator first. That's usually achieved with a simple (and very small) buck converter. As far as my tests show, this seems to be successful, though I haven't tested it for more than a few days. 

One alternative for Heltek is to use the much more complex Waveshare regulator. This is a bit more expensive, physically larger and uses around 16mA continuously, simply by virtue of being connected up. Whether that is too much current draw depends on where you are and how active your board might be.

Waveshare solar power manager module. Nice item, though the screw connectors are never my favourite, and it consumes 16mA at all times when connected, which may or may not be an issue, depending on your location and board activity levels.

 

Another option is to buy a 6V-rated panel which has a buck converter and USB connector glued to the back. This works very well for me on a field-deployed Heltek V3 (not V4, though it should be fine for that, too). The only issue is that these boards tend to be of the flexible type, which can be a problem in field deployments, where a solid surround is usually needed. Also, the USB connection needs either to be modified to a permanent, wired solution, or else protected with sealant of some form, so that the whole thing doesn't rust to bits in the outside environment (which will happen quickly otherwise).

Be aware that directly connecting a supposedly 6V panel, especially of the 'CCTV', smaller types that are widely sold, can result in failure of your boards, regardless of type, because they will often exceed 7V output. Those types of panel, whilst fine in very sunny locations with little cloudy weather, are absolutely useless otherwise. Even on a bright day with cirrus obscuring the sun a little, the output falls to very low levels.

  

 

  

LoRa Coax Losses.

Recently, I installed a test solar repeater at a remote location. This was entirely to assess the reliability of such a system and whether anything might need improving in time.

My test solar repeater, with its short RG174 coax (now changed).

 

As a test, I simply used a 1m length of RG174 coax as part of a pre-made connector to hook up the McGill Microwave Systems 4.5dBi colinear vertical to the Heltek V4 board.

On showing a picture for interest on Facebook, the inevitable 'oh, you shouldn't do that!' comments began to roll in. 

First, I 'shouldn't put an antenna in somebody else's field at random, without permission'.

Er, I've been given a personal easement to use this field and structures 35 years ago.

Then, I shouldn't use 'that very thin wire for a long run; it will defeat the gain of the antenna'.

Er, the cable is 1m long. 

The pole the antenna is fixed to is simply to hold it clear of a roof and little else. Great height isn't feasible and neither is a larger antenna at this very exposed, remote location. The antenna-coax combination was an entirely reasonable system, given what I had available and that it was a short run and that a 1/4 wave antenna using the same RG174 cable assembly had already been shown in earlier tests to give perfectly adequate performance from the same location.

Another factor, significant for me, was that thin coax needs only a narrow hole to be cut through brick walls - in my case, by hand drilling. Wider cable needs a larger hole - very difficult to drill by hand, especially above head height, and otherwise excessive and unsightly for some on a house wall. 

All the same, the question as to whether RG174, which is widely used, almost as standard for LoRa applications, is really so lossy as to require replacement in most cases.

Undoubtedly, RG174 has extremely high losses at or around 868MHz; Farnell's datasheet gives 105dB per 100 metres, or 1.05dB per metre. So any runs much greater than my own 1m length would, indeed, present losses that most people would deem unacceptable, except perhaps where a directional antenna was in use. Even then, a run of more than 2m would really need better coax.

LMR400 coax.

 

The usual alternative is LMR400. In ham circles, we've been pre-conditioned to expect high prices for long runs at HF or VHF, made worse by US-centric discussions online, which usually have very much longer runs to antennas than those in the UK.

In fact, a pre-assembled LMR400 coax of (standard) 3m length for LoRa comes in at just  £19, delivered (mainland UK). This is the kind of length many would choose for an antenna situated on a house wall to be fed from indoors, for example.

RG174, thin coax.

 

The benefit of LMR400 is the low loss: at 868MHz, it's around 12.8dB per 100 metres, or 0.128dB per metre. With a 3m length, the loss is 0.38dB, or already 0.66dB less than just 1m of RG174.

So, is the use of LMR400 and its relatively high price, worth using?  For runs of 2m or less, for most people, no. Beyond that kind of run, LMR400, or even the cheaper and slightly higher loss (~0.193dB/m) X-400, rapidly leaves RG174 in the dust, keeping losses within tolerable limits until one reaches around 15-20m runs or so. Above this length, a better antenna and/or even more expensive, lower loss coax will come into consideration.

 

 

SDRConnect: The Linux Installation

There's a lot of chatter at the moment about how Windows 11 is forcing everyone towards a 'forever rent' model i.e. paying every month for cloud-based computing that you previously ran locally. It's being called 'the end of personal computing' by some.

Whether through use of Raspberry Pi SBCs or more concerted efforts in replacing a computer's OS, most amateur radio operators will have something answering to the Linux label in their shacks.

And so it has long been with me. But I'm no Linux expert - at all. I do enjoy the more interactive aspects of delving into the terminal and actually entering real commands from time to time. But it can also be a bit difficult and frustrating to get to grips with.

I'd tried to install SDRConnect on Linux Mint a few months ago, but I hadn't really gone to much effort to overcome the hurdles I met. Last night, I wiped my 12 year-old HP laptop clear of Windows and Zorin OS, installing only Ubuntu. What follows, though, also applies to Linux, which I tested this morning.

Most of what you need to know is actually on the SDRPlay website, but isn't really that obvious a place to hit during a stressed visit, trying to figure-out how to get the damned software running! It's on a PowerPoint-type page:

The commands are: cd Desktop (or cd Downloads, depending on where you have the downloaded SDRConnect .run file) Note that the directory names are case-sensitive.

Type ls to list the files in the relevant directory. Somewhere, you will see the SDRConnect file with a '.run' at the end. You can highlight and copy this filename to the clipboard to paste it when it comes to the commands.

Now type chmod 755 SDRConnect.[whatever the rest of the filename].run You can paste the filename from the clipboard.

Now type ./SDRConnect[rest of filename].run  Note there is no space between the ./ and the filename.

The user agreement and installation now goes ahead. But if you are missing some files, it will tell you to run the installation of SDRConnect again after downloading and installing the missing ones; it's usually very simple and just one file.  Just go back to the ./SDRConnect[etc] instruction, above, when the missing files are sorted.

You should now find SDRConnect installed and an icon and/or listing for the software.

Easy! Works for Ubuntu, Raspberry Pi OS and Linux Mint so far.

 

 

 

 

 

868MHz DX

It was a very bright, sunny day today, though icy cold when the sun went behind a cloud, up on the few high spots on Anglesey - Mynydd Parys. This is 139m above sea level, with a clear line of sight across the Irish Sea to Cumbria, the Isle of Man and the Mourne Mountains in Northern Ireland. It's a great place for radio, and where I lived for 13 years.

Beaming northern Cumbria...

I had a bit of a stroll up there and took my 8-element AliExpress Yagi along with a GPS-enabled Meshcore transceiver. A convenient concrete block to stop people driving over the historic copper mine tailings heaps provided a useful level surface on which to rest the antenna. 

Cumbria, seen early morning from Mynydd Parys, with background lighting revealing the landscape clearly.

 

Aiming it by eye at northern Cumbria, I was quite surprised to make a direct, 'zero hop' connection with a repeater on Lank Rigg at 137.6km distance. Given this is UHF and the power output only around 0.15W - admittedly boosted by the Yagi's ~10dBi gain to an effective 1.5W, that's pretty good going!  As you can see from the screengrab of the app, below, the direct 'ping' signal there was -13dB and -6.25dB back to me (the rest of the information on-screen is redundant for the ping test). I don't know what the antenna arrangements are in Cumbria.

 

Irish Sea area, showing me (north coast Anglesey, purple dot) and the MCC Lank Rigg repeater that heard me.

 

Cornwall, Some Years On.

Back in 2015 - still not that long ago to my mind - the RSGB waded into what became a political farce, about which I was reminded this morning on reading The Guardian, and its piece on widening celebration of Cornish identity in the region. 

The issue all those years ago? The regional secondary locator (RSL) that OFCOM had decided to grant, on a permanent basis, to Cornwall (Kernow in Cornish, hence the 'K').

Source of hostility by the RSGB in 2015...

This came about as a result, in 2014, of the Cornish being granted National Minority Status, recognised by the UK Government, under the European Framework Convention for the Protection of National Minorities. This brought them into line with the Scots, Welsh and Irish, who had enjoyed such recognition from a much earlier point.

Of course, the bigwigs at the RSGB had other ideas. They issued public announcements of support, whilst rabidly opposing it from the very outset, as soon as they thought they were behind closed doors in meetings with OFCOM.

OFCOM itself added, inevitably, to the mess. It formally involved Cornish MPs by telling them all about the new, permanent 'K for Cornwall' callsign, only to withdraw the whole thing, making it a mere temporary issue, ultimately negotiated to last a year.

The reason for the change of heart at OFCOM?  It was never explicitly said, but minutes obtained under FoIA at the time revealed pressure from the RSGB, to which OFCOM seemed unreasonably willing to bow. 

The RSGB raised the entirely specious spectre with OFCOM that, if Cornwall got its own, permanent RSL, then the country - Lord help us all - could be faced with "wide repercussions" - angry mobs from all over the UK, shaking their pointy antenna sticks at the government and threatening regime change and perhaps the collapse of global civilisation itself. The RSGB, desperately, added that operators across the world would be "confused" by the K RSL. Radio operators are not known for being confused by callsigns and geography.

The Guardian article today contains a beautiful line that anyone who is from one of the National Minorities will strongly identify with and understand: "I'm Cornish. I'm definitely not English". To the English ear, this sounds like a declaration of war; that having a minority identity means you are saying you hate the English. Which is, of course (usually), utter bilge.

Why did the RSGB react in this way, advancing ridiculous and clearly disingenuous arguments to overturn what OFCOM - a government agency - had already decided?  Seasoned critics opined, perhaps not unreasonably, that it was concern from within the ranks of the obsessive contesters, including from the within the ranks of the (non-Cornish) Board, that led them to believe they would be at some disadvantage in their pointless point-gathering of a weekend. Think about it: a hobby society, unaccountable to anyone, somehow forcing UK official policy to be changed, making a fool of OFCOM and its decision.

To the wider world, it was a non-story. To the Cornish and those in the UK who are not English, it was another typical English dirty trick, reminding us all of how petty, oppressive and loathsome they can be. Rather than celebrate Celtic cultures - here way, way before England and English ever existed - the English-centric RSGB and its black-suit-(but no black Board members)-and-tie ways decided to have a tantrum and break everything. They were clearly very satisfied with it all.

The Guardian today, celebrating growing Cornish pride, simply reminds us how disgracefully out-of-step with UK cultural history the RSGB was and, no doubt, still is. A word commonly used to describe such prejudiced responses to issues like the RSGB exhibited towards Cornwall is: 'gammon'.

If you're really bored, you can trawl through my blog to find the several posts I wrote at the time. If you're only mildly interested, you can just read my letter to the then Managing Director, or this summary from a bit earlier. Whilst it's a while ago now, it does tell you a lot about our so-called representative body, the Board of which today still contains some of those around at the time.

 

Meschore Continues

It's been a busy few weeks, including getting to grips with Meshcore and its various elements.

Luckily, there's a repeater within line-of-sight - just - of me and this helps develop the interest. Slowly, more repeaters are appearing across Anglesey and, come summer, this may well pick up significantly.

Attention in the past couple of weeks has turned to antennas. At home, a window-placed test 8.5dBi collinear from Paradar has proved to work perfectly well, although it doesn't really offer any advantage in what can be heard in practice over what the stock stubby antenna was delivering. Not really planning to stay at this property much longer, I've resisted putting this antenna outside and stuck it in the loft instead. It does OK there.

With one unit tied up in the loft, I decided to buy a Heltec V3 with GPS and a 3-D printed case, so that I could shove it in a rucksack and take up the mountains - or just a hill overlooking the Irish Sea on Anglesey. The weather being so wet, though, I haven't managed to get out to do this!

Instead, I've been testing the handheld unit out on my daily walk around the local reservoir, which is surrounded by a relatively narrow strip of conifer trees, which of course have pretty dense branches and needles - very effective in blocking microwaves!

 

The only place I could get a signal from the handheld's stubby antenna to my home was from an old railway embankment across a lake that has a relatively clear line-of-sight path (orange and turquoise positions, both at ~2km). From any position on the dam (pink and white positions), which has a path through 250m of conifers and also lies behind a low hill on which they grow, I couldn't get a signal back home with the stubby. 

Line-of-sight (terrain) map for the dam. LoS is only in the clear areas, free of dark lines (the upper end of the lake isn't correct, because it fails to properly take into account the effect of the trees).

 

I felt I could do better than this, despite the very low power involved (22dBm, or 160mW). 

So I built a simple 1/4 wave vertical with four sloping radials, based on a N-type panel mount socket with a SMA connector on the other side. I simply soldered the radiator into the centre of the N-type and attached the radials to the panel mount holes. With a bit of trimming, I got a nice matching curve with about 1.25:1 SWR. It's probably best to grind the thread mounting down to the level of the centre pin socket, or slightly below it, to avoid the lowest few mm of the radiator being somewhat inside a grounded surround of metal. I fixed the whole thing to a timber stick using a 15mm PVC pipe clip, into which the N-type screw thread mount fits snugly.

The Heltec v3 attached to its stick-mounted vertical.

 

So, looking more of a nerd than ever, off I went for a walk with the handheld, but now connected to the new vertical antenna. I was only going to send one test 'advert' signal from the most challenging position - the nearest point on the dam, at 1.8km exactly and through all those trees and a low hill. Would it get through?

Satisfyingly, it very much did! It's no surprise to anyone who has used stock stubby antennas that they are very poor and something to be discarded as soon as possible. And so it is at 868MHz. 

Success! Signal heard back home from the dam.

 

Of course, a PVC tube collinear is more convenient and robust to carry around that a spidery vertical for mountain hiking, for example. But it's also not an impossible antenna to carry in your hand or sticking up from the backback.

Very satisfying experiment, costing no more than the price of a N-type-to-SMA panel mount connector.

Incidentally, at the moment, you can save yourself well over £20 if you buy the same ~6dBi collinear from McGill Microwave Systems rather than the popular Paradar outlet. 

 

 

 

Meshcore: overcoming the issues

Yes, I'm still alive!

I recently started experimenting with Meshtastic - this lasted less than a day - and straight thereafter onto the much better Meshcore 868MHz network.

Though I live in what is to many a 'remote' area, with not that many active radio people about, I was surprised to find two repeaters on Anglesey and a couple of client nodes over on the mainland. 

Having kicked-off using just the standard stub antenna, I decided to spend the £68 for a Paradar 8.5dBi antenna (1m-long collinear). This is nicely made, though I'm not entirely persuaded by the sealant on the end caps, which remains unset on receipt. A quick spin with the self-amalgamating tape is therefore advisable. The mild steel bracket supplied is also poor; it will rust to bits in no time, especially in a salty sea air environment like mine. You can currently save yourself about £10 on Paradar's direct-to-consumer site if you buy via E-bay; you get the self-same antenna and DHL delivery (from Germany).

The Heltec V3 was easy to flash and configure as a client, and the Meshcore app connected to it, straight away. It's important to remember that flashing requires you to use Microsoft Edge browser.

I didn't have quite the same easy experience with the V4, which I ordered via E-bay from China (which, as always, arrived in just a few days - quicker than most UK sellers can manage!)

The problem I had was largely one of ignorance. Firstly, the V4 I have needs its 'User' button (the top one) pressed on powering-up in order to put it into flashing mode. Once I understood that, flashing via the Meshcore online site was simple enough. 

Where I had a day of scratching my head was: why couldn't I connect to the flashed V4 immediately after this process, which used the exact-same serial (USB-C) connection, in order to configure it?

Turns out that it's a matter of rather clunky sequencing: you put the unit into flashing mode with the 'User' button, do the flashing, disconnect the V4, then reconnect it in the normal sense, such that it powers-up, goes through its 'Please wait' thing and then displays the repeater settings for a while. When the screen went blank, I clicked on 'Configure via USB' on the flasher site (I left the flashing page open and didn't touch it until the Heltec's screen was clear). I then got the configuration screen and I was able to sort everything out.

I used the following settings (you can find out what everyone in your particular area is using from the Meshcore nodes map). You can also just choose 'UK/Narrow' from the app and it will auto-fill the settings for you:

Frequency: 869.618MHz
Bandwidth: 62.5kHz
Coding rate: 8
Spreading factor: 8

This immediately worked and was immediately seen by my client in the other room. I've yet to figure out GPS integration on the V4 board, but that's just a matter of developing enough patience some other day!

Incidentally, using the Paradar antenna at the window, on 30/01/2026, I received a repeater in Greystones, south of Dublin, at 115km! No tropo, no line-of-sight. This was either an aircraft reflection or someone who had come across to Wales on the ferry, setting off a ping or two on Anglesey, having not changed their repeater settings. I will have to try and communicate with the owner to find out!

I later discovered why my repeater wasn't sending periodic flood notifications; I hadn't logged-in to it via the phone app, using the password I'd set. This is very confusing, because if you log in with no password, it lets you do so, but has very few options (because you'd be a guest logger-inner in this case).

When I did log in with the password, I saw I was now logged-in as an admin and all the settings were now available. I still have no idea how to enable the GPS so that's still a wrestle for another day!

NOTE: If you switch off your Meshcore repeater and it has no battery attached, your settings will remain in place on powering-up again, but the repeater's clock won't. So you will need to re-sync the clock from the phone app.