Experiments with Meshtastic – PMB-NZ

Since mid-2025 I’ve been looking at Meshtastic. Using T-Beam and Heltec V3 modules and the Android App. Initial testing was indoors on the workbench which then moved out into the back garden.

It’s On the Roof

This is the original roof mounted Meshtastic node. On a pole with a weather station wind and rain sensors.

The Meshtastic node is inside the 40mm DWV (drain waste vent) pipe with 3D printed top cap and lower pipe clamp brackets.

The original T-Beam Meshtastic module was connected to wifi as Bluetooth is not reliable on the roof. It won’t run wifi and BT at the same time.

Note: 3D printed (PLA) parts are not fully waterproof but are good enough in this application. The top cap doesn’t seem to leak. The mounting bracket/clamps probably do, having hollow cores but have been fine so far. Red filament fades to orange quite quickly but over several years outside in the direct weather I haven’t notices any structural issues. Aluminium bars, 3D printed clamps in 2 halves, secured using 6mm stainless bolts.

Original T-Beam Module

The T-Beam module is attached to 3D printed supports that slide into the 40mm pipe. A short coax connects to the bandpass filter and then a 3dbi antenna.

Note that the right-angle SMA antenna connector on the T-Beam board has been rotated 90-deg. This requires some careful soldering and cleaning to keep the board safe.

We are located about 200 meters from 2 cell towers and the 915MHz Meshtastic band is between the cellular up and down bands. This creates a high noise floor over the band and wipes out Meshtastic.

Without the filter Meshtastic works if not higher than about 2M above ground which limits coverage. Mounting high should in theory improve coverage but is completely wiped out by the cellular systems. Adding the bandpass filter eliminates the cellular interference allowing the coverage benefit from increased mounting height.

The lower end 3D printed support carries power and environment sensors connected via I2C to the T-Beam module. A 4-pole waterproof connector connects a 4-core cable to a solar panel with mppt charge module and battery inside the roof. When connected to a solar panel and battery, the power monitor allows Meshtastic to monitor the battery charge/discharge.

In our case, a junction box at the bottom of the pole combines the Meshtastic power with weather sensors into one Cat-5 cable into the roof. All waterproof connectors which seem to be reliable outdoors.

The image shows a ESP8266 based weather board boxed mounted inside the roof. A solar panel, MPPT change module and battery supply 12-14V. A Cat-5 cable connects outdoor weather sensors and supplies power to the Meshtastic node.

The 30 Watt solar panel and 20Ah 12V SLA battery are easily able to cope during summer but struggle occasionally during mid winter, requiring an external boost. This also powers 4 small indoor night lights. More battery capacity would probably solve it, maybe also a larger solar panel.

T-Beam WIFI problem

After a while of operating Meshtastic connects to wifi but the web browser and Android app will not connect to the node. The longer it runs the worse it seems to become. Updating the Meshtastic firmware doesn’t solve the problem. I have read that a complete flash erase and reprogram will solve the wifi problem. I haven’t tried this yet.