I started testing Meshtastic and Meshcore recently. I don’t really need them right now, but I like the idea of sending a message to someone else without relying on a mobile provider or the internet. It’s not a very expensive hobby and gives me a reason to go out to other areas, explore, see if the system works, etc.
I want to add some coverage at home as I don’t get signal from anyone else. While I can’t install an antenna outdoors, I can put something on my window and provide signal for a few hundred meters. Since I’m not taking these with me and power is always available, just a board and antenna is fine. I ended up buying two cheap Heltec V3 (two because I want to run a node on each mesh). For the case, I decided to copy an idea that I had seen online before: adapting the case it comes in to give it some protection and mount the antenna.
Here’s the thing, on the videos I’ve watched, sometimes the antenna is mounted on the side that has the hinge, sometimes people attempt to remove the sticker on the “front” of the case (which leaves glue behind), etc. Not always ideal. This is how I did it, with the help of a precision knife:
- The screen faces the bottom/rear of the case. No need to remove the sticker and clean the glue.
- The lid opens horizontally. It could also open vertically, with the latch at the top to prevent it from hitting the antenna.
- The antenna is close to the corner so there’s space in case I want to add something later on (e.g. GPS module). Don’t go too far to the corner as you want the antenna to be straight. I have mine on the opposite side of the USB-C port, just in case it causes some interference.
- The USB-C port is on the side (near the latch). I could have it at the bottom, but this allows me to leave it standing on a table, for example. In my case, that’s also the side where the cable with power comes from.
- I’m using the foam to keep things in place. I made a small cut to avoid bending the antenna connector/cable.
I’ve also decided to use these pins to hold the board to the foam, so it doesn’t move around. It doesn’t seem to be conductive and lets me plug or unplug the cable if needed without opening the case:
And this is the Heltec V3 inside the modified plastic enclosure and with the antenna attached:
Things to consider:
- Size of the hole for the USB-C port. I made the hole larger than needed as I was planning to have part of the cable going inside the case, but as it turns out, I could keep the USB-C port very close to the edge of the case with the help of the foam + pins to hold it in place.
- Consider where the antenna will be. You want antennas to be vertical, so the top is the logical place to place them. However, if you plan to use this in a static place and want to have 2 antennas for 2 different mesh networks, you’ll need to leave some space between them to avoid interference. Depending on the space you have, you may have to go with vertical spacing (one at the top pointing up, one at the bottom pointing down), so check where the holes need to go to avoid having the display upside down or the power in the wrong side.
- Speaking of antennas, based on social media comments, plan to have the antenna extended/open while in use. Some antennas let you fold them 90º, but it seems that it can affect signal. If you plan to have the antenna pointing up, then put it at the top of the case instead of having it on the side and then bending it up.
- I’m no antenna expert, but the antennas that come with these kits seem to be bad, especially to transmit. You may want to consider getting some better ones at some point.
If you’re wondering, I ordered the Heltec V3 from Aliexpress. The 2x kit was cheaper in my case as I wanted 2 of them.
If you’re buying these for the first time, make sure that:
- Pick the right one for your region. They’re usually available in 433 MHz, 868 MHz, and 915 MHz. In Europe, most people seem to use 868 MHz as power limits are higher than 433 MHz. In the US it’s usually 915 MHz. Check what’s popular (and allowed) in your area. Keep this in mind when buying antennas too.
- These boards come with and without displays. I got mine with displays because it’s just easier to see if something’s wrong, but usually they’re slightly more expensive.
- Some boards come with an antenna cable that doesn’t let you replace the antenna. I believe those are mainly for small enclosures. Mine have the “SMA connector” at the end, which lets me screw a new antenna if I want to.
And one last thing: no matter what you do, NEVER POWER THEM UP WITHOUT CONNECTING THE ANTENNA. You can kill part of the board if you do that.
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