Industrial monitoring application
LoRa Antennas for Tank Level and Vibration Monitoring
Both of these sensors sit on or inside metal, and metal is what decides the antenna. This guide covers getting a LoRa link out of a steel tank, a pump housing or a machine frame, and surviving the vibration and temperature that come with it.
Use this guide to
- Get the antenna off the metal and into open air.
- Choose between screw, magnetic and cabled mounting.
- Pick a connector that survives continuous vibration.
- Prepare the mechanical details we need before quoting.
Quick answer
For a tank level sensor on a steel vessel, put the antenna outside the metal on a screw or magnetic mount and keep the coax short. GL003-868 (868 MHz, 3 dBi, SMA male, screw mount, φ46.6 x 14.5 mm) is the low-profile option through a housing wall; GL822-868 (868 MHz, 3 dBi, magnet, VSWR <1.5) suits a temporary or retrofit install. For a vibration sensor bolted to a machine, the mechanical joint matters more than the RF: a short rigid whip like GL-DY403-868 or GLR01 on a properly torqued SMA connection beats a longer antenna on a cable that will fatigue.
Where the tank farm or plant is large and the gateway is fixed and far, a directional GL868V-14 (820-890 MHz, 14 dBi, N female, pole mount) at the gateway end is usually a better investment than upgrading every node.
Metal is the whole problem
A LoRa antenna inside a steel tank or a cast pump housing does not have a reduced link budget. It has effectively no link. Sheet steel is a shield at 868 and 915 MHz, and no gain figure recovers what never leaves the enclosure. So the first design decision is not which antenna, it is where the antenna leaves the metal.
There are three workable arrangements, and one that only looks workable:
Through the wall, low profile
A screw-mount antenna in a drilled and sealed hole. GL003-868 is 14.5 mm tall on a 46.6 mm base, so it survives places where a whip would get knocked off. The sealing at the hole is your design, not the antenna’s rating.
Magnetic, on top of the tank
GL822-868 or GL8681 (863-870 MHz, 3 dBi, SMA male, magnet, 31 x 91 mm) with the coax routed back to the electronics. The tank roof becomes the ground plane, which usually works in your favour.
On a short mast beside the vessel
For insulated or non-metallic tanks, or where nothing may be drilled. Adds cable, so keep the run short and account for the loss.
What does not work
An internal antenna behind a steel lid, a whip lying flat against the tank wall, or an antenna inside a metal junction box with a plastic window that is smaller than the antenna. We have seen all three specified, and all three fail on site.
Vibration changes what fails
On a rotating machine the antenna itself is rarely what breaks. The connector, the cable and the strain relief are. Continuous vibration works an SMA joint loose over months, then the VSWR drifts and the link degrades in a way that looks like an RF problem and is actually a mechanical one.
- Keep it short and rigid. A stub antenna directly on the housing, such as GL-DY403-868 (Ø8 x 51.5 mm) or GL-DY8681 (Ø5.5 x 167 mm), has far less leverage on the connector than a long whip on a flying lead.
- Do not let the cable carry load. If coax is unavoidable, clamp it within a short distance of the connector so the joint never takes the movement.
- Specify the torque. An SMA connection tightened by hand is a future failure. Put the figure on the assembly drawing.
- Check the real temperature. A sensor on a pump or compressor housing runs hot. GL-DY403-868, GLR01, GLR03 and GL86803 are rated to +85 °C; if your surface runs hotter than that, the antenna needs to move off the machine.
Models we can quote for industrial monitoring
| Model | Frequency | Gain | Connector and mount | Size | Temperature |
|---|---|---|---|---|---|
| GL003-868 | 868 MHz | 3 dBi | SMA male, screw mount | φ46.6 x 14.5 mm | -40 to +85 °C |
| GL822-868 | 868 MHz | 3 dBi | SMA male, magnetic, VSWR <1.5 | 29.4 x 89 mm | -40 to +85 °C |
| GL8681 | 863-870 MHz | 3 dBi | SMA male, magnetic | 31 x 91 mm | -40 to +85 °C |
| GL-DY403-868 | 868 MHz | 2.5 dBi | SMA male stub | Ø8 x 51.5 mm | -40 to +85 °C |
| GL-DY8681 | 868 MHz | 3 dBi | SMA male | Ø5.5 x 167 mm | -40 to +85 °C |
| GL86803 | 863-928 MHz | 3 dBi | SMA male | 14.5 x 220 mm | -40 to +85 °C |
| GLG4101 | 868 MHz | 3 dBi | IPEX or other, RG178 / RF1.37 or other, knuckle mount | Per assembly | -40 to +85 °C |
| GL868V-14 | 820-890 MHz | 14 dBi | N female, pole mount, VSWR ≤1.5 | Directional Yagi | -40 to +70 °C |
None of these publishes an IP rating. On an outdoor tank or a washdown area that is a real requirement, so tell us the figure your specification needs and we will confirm it against the datasheet revision we would quote, rather than repeating a category-level number.
Tank level and vibration are the same antenna task
They look like different applications and they are usually bought by different people, but from an antenna point of view they are one problem: a small radio attached to a large piece of metal, in a place where nobody wants to run a cable. Solve the mounting and the sealing, and the RF part is straightforward.
What genuinely differs is duty. A level sensor may transmit a few times an hour and sit still for years, so mechanical robustness matters more than anything. A vibration sensor transmits more often and lives on a moving surface, so the connector and cable design carries the risk.
What to send us
- Radio module and the exact LoRa band it is certified for
- Sensor type and where it physically attaches
- Tank or machine material, wall thickness, and whether drilling is allowed
- Enclosure drawing, available antenna area, and any height limit
- Connector on the module, plus cable type and length if needed
- Real surface and ambient temperature, including process heat
- Vibration profile, washdown, chemical exposure and any required ingress figure
- Quantity, and the drawings or test records you need with it
Related pages
See the full LoRa and LoRaWAN antenna range, or outdoor LoRa gateway antennas for the gateway end of the link. If the range is short despite a correct antenna, work through the LoRa gateway range troubleshooting guide. For a non-standard band, cable or connector, start at custom LoRa antennas.
Ask for an industrial monitoring antenna review
Send the mounting drawing, the tank or machine material and the temperature range. We will shortlist from the models above and flag what has to be proven on your hardware.
