But what can we make of the signals?
Written on the Ipswich-to-London train and dispatched to silicon.com via a free wi-fi hotspot in the capital at 12.5Mbps later the same day.
We all swim in a sea of radiation from radio and TV broadcasters, mobile phones, public mobile radio, walkie-talkies, games consoles, wi-fi and much more. Monitoring where the radiation hotspots are can tell us a lot about people and sections of our society.
As I travel the planet, I periodically scan the airwaves for signals and wireless activity. This habit is usually motivated by pure interest but sometimes it allows me to diagnose connectivity problems in real time. The results are always interesting, and sometimes very surprising.
To illustrate the diversity of recent scans, I have selected four very extreme examples in the 2.4GHz wi-fi band. The first is a UK retirement community, where it would appear no one is communicating.
The second example is right at the other end of the age spectrum, with a cluster of teens and younger children online with a variety of devices. Here the electronic and verbal communication was intense, continuous and augmented by a lot of physical interaction through keyboards and screens.
The third example is a secure facility operated by a company where all communication and access was tightly controlled and monitored. Here we can see definite evidence of control. Surprisingly, it was suggested that there was no radiation on, in, or off the site.
However, I could see some activity - authorised or not - and I would guess it was for specific and specialised purposes and involved a great deal of encryption and protection.
The reality is that containing or keeping all radiation out is a really big and difficult problem. Even a Faraday cage will leak, and tinfoil is...