WLAN Reception Cistern

Especially with cisterns or tanks in the ground, WLAN reception can be severely impaired. That's why Senvolon offers two versions of the level sensor – one version with an **internal WLAN antenna** and one with an **external antenna connection**, to be able to use a separate antenna. For an external solution, **outdoor antennas with a 3-meter cable** have proven particularly effective. These reliably guide the WLAN signal out of the shaft, ensuring a stable connection for the sensor. This guide will help you decide which sensor variant is suitable for your scenario and how to properly assess WLAN quality.

1. Check WLAN reception at the cistern

You can easily test this:

1. Go with your smartphone to the spot where the sensor will later be located
2. Check the WLAN signal strength
3. If there is no or hardly any reception, use a WLAN repeater to extend the signal to the cistern

2. Influence of material on WLAN reception

Damping depends heavily on the material and installation depth:

• Plastic largely allows WLAN to pass through
• Concrete significantly reduces the signal
• Steel completely blocks WLAN

The decisive factors are primarily:

• the material of the lid
• the depth at which the sensor is mounted

The deeper and more massive the material, the more difficult it will be to get a stable reception.

3. When an external antenna is necessary

An external antenna is recommended for:

1. Steel lids
2. Reinforced concrete
3. Generally weak WLAN signal
4. Deep-lying sensor positions
5. Cisterns or shafts in outdoor areas

In these cases, the antenna should be mounted outside the shaft or cistern.

4. Check WLAN signal strength in the level meter (RSSI)

After installing the Senvolon sensor, you can view the reception strength under More. This is displayed as the RSSI value (Received Signal Strength Indicator).

Form:

• Unit: dBm
• negative values
• closer to 0 = stronger signal

Examples:

• -30 dBm: very strong signal
• -90 dBm: very weak, unstable

5. Evaluation of RSSI values

For the level sensor to reliably send data, the value should not be worse than -80 dBm.