Make a Laird Sentrius an outdoor gateway

The Laird Sentrius LoRaWan gateway is a low cost, stable and easy to configure on The Things Network gateway. They are indoor gateway. I want to install it outdoor to offer a better coverage.

In certain situation the easiest way to install it outdoor is to use an external antenna and a long antenna cable. In some other situation this approach is complex to implement and the easiest way is to install the gateway outdoor with its antenna and network connection.

The best is to use an outdoor LoRaWan gateway. The price is usually > 600€. Even if in general the outdoor gateways includes GPS and Cellphone connectivity. In this post I’ll explain how I make one of Laird Sentrius outdoor because it costs less than 250€ for the gateway itself.

Requirements

The objective is to have a cost effective LoRaWAN gateway with the following features:

  • Outdoor resistant
  • With an outdoor high quality antenna
  • Powered over Ethernet

Equipment

To answer these requirements I found the following equipements

  • Gateway: The Laird Sentrius on Digikey (250€ w Tax)
  • Outdoor Antenna: The Taoglass OMB868Mhz on Digikey (125€ w Tax)
  • Outdoor Plastic box: 310x250x125 from Amazon (26€ w Tax)
  • Platic box fixation: Metronic fixing plate from Leroy-Merlin ( 15€ w tax)
  • PoE adapter kit: Tp-Link have a nice product with power level adaptation and compatible connectors TP-POE200. From Amazon (20€ w Tax)
  • Fixing mats: 2 meters, extendable, Metronic from Leroy-Merlin (13€ w tax)
  • Antenna coaxial: It needs a RP-SMA-Female to N-Male cable, 3m. I ordered a Tp-Link TL-ANT24PT3 cable found on Amazon (8€ w TAX)
  • Network cable: I selected a flat Ethernet cable to be able to pass it over a closed window. 30 meters regarding the place where it needs to be installed. I found it on Amazon (17€ w Tax)

The total is about 450€ to have an outdoor configuration with a high quality antenna.

Gateway configuration

The choice of the Laird Sentrius gateway makes easy to join TheThingsNetwork LoRaWan IoT network. To complete this setting you may take a look on my post about the Laird Sentrius configuration.

Mounting

The first step is to mount the fixing plate on the plastic box:

The fixing plate is centered. I’ve chosen to use 4 screw of 3.5mm diameter and I’ve made a little smaller hole on the plastic box to ensure no water will enter from it.

Now we can fix the Laird gateway inside the box.

It has been an unexpected stroke of luck: this plastic box have different screw holder an the diagonal of them is corresponding to the Laird gateway length. I’ve been able to screwed it as shown on the the right picture

After this step, I’ve been able to add the add the PoE splitter. I’ve used double-face adhesive tape to fix it on the plastic box bottom. The network wire is passing through the plastic box. I’ve made a knot on the Ethernet cable to protect it against stretching. The PoE splitter is switch to 12V. The connector provided by TP-Link is the same as required for the Laird Gateway. That choice was perfect. Today I’m really lucky.

The next step is to pass the antenna cable. The RP-SMA side is easy to pass through the plastic box. You just need to drill a little hole it will extend to the right side on its own.

The antenna wire is passing under the laird (works also after being screwed) to keep it as straight as possible. I’ve added a big screw on the top right on the picture and attached the antenna cable on it. This is to protect it against pinch.

I’ve also add a plastic anchor to protect the antenna cable against stretching.

The last steps are to close the box and fix it on the mat. For the transportation, the antenna is not yet fixed on the top of the mat.

The antenna is coming with a specific black waterproof scotch-tape to protect the connector from the weather condition. It have to be put around the antenna connector once connected. Pull on it when putting it around. Press on it to ensure it is correctly fixed.

The plastic box is only IP55, I need to see what will happen in real conditions because this box have everything to be waterproof but I was not able to screw it to make the seal in contact of the top of the box.

On site installation

The on-site installation was done under the snow 😉 I’m actually not 100% confident about the network cable as I’m not sure it will work correctly for a long duration with external weather conditions. We will see it in a couple of months. Apart this point nothing specific to notice for now. I’ll update this post with a longer experience. Feedback is coming later.

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