Wireless LAN measures how far the wireless LAN can reach even if there is a wall, measuring the radio field strength with products for companies and homes

When wireless LAN is enabled outdoors, multiple SSIDs (character strings that identify access points) are displayed as connection destination candidates. In addition to the SSIDs of communication services provided by telecommunications carriers and public institutions, there are also many SSIDs of access points that are believed to be installed in companies and ordinary homes.

It is not uncommon for networks to authenticate using a common character string (passphrase) among these SSIDs. If a third party obtains the passphrase, the risk of network intrusion increases.

Then how strong the radio waves are reaching the outside. This time, we measured the strength of the radio waves reaching the other side of the wall.

Scenery of the experiment. Using a dedicated device that can measure radio wave intensity (Source: Photographed by the author, same below) [Click image to enlarge]

In the experiment, we prepared two cases in a commercial building with multiple companies.

In Case 1, we measured the strength of the radio waves reaching the other side of the wall about 1.5m apart. The interior of the wall is believed to be made of reinforced concrete, but the exact situation could not be confirmed. However, the surface of the wall surface looked like concrete both front and back. Also, the access point was not surrounded by walls on all sides, but it was necessary to go around several dozen meters or more to avoid the walls.

In case 2, we measured how far the radio waves of the access point installed in the room surrounded by doors, plaster walls, frosted glass, etc. reach the outside.

There are two types of access points: a product for businesses that is installed on the ceiling and a stationary product for home use. Settings such as radio wave output were left at their initial state. Also, the frequency band was measured at both 2.4GHz and 5GHz.

Ceiling-mounted access point for businesses [Click image to view larger image]

Next page Signal strength drops significantly when there is a 1.5m wall