While here in Boston with the Shuttleworth Foundation, I decided to take the opportunity to see what kind of coverage we can obtain with a Mesh Extender in my hotel room.
My room is on the 7th floor of the Kendall Hotel in Cambridge, which provides a good vantage point in amongst buildings that are often 10 - 20 floors. I put the Mesh Extender on top of the wardrobe in my room, and set about walking around the local area to see how far the signal would reach.
You can get an idea of the coverage in the map below, generated using the coverage mapping tool written by Loïc, one of our students. This tool reads the signal strength directly from Mesh Extender via the ServalD HTTP interface, and merging it with a GPS fix from the phone. The resulting trace is processed with some scripts to produce an HTML page that overlays the data points on Google Maps.
We expect to release the mapping tool in the next few weeks.
You can see that coverage in this case extends one to two blocks. Not surprisingly, range is shortest when faced with the tallest buildings, e.g., through the Boston Marriot Hotel. Nonetheless, the signal almost always appears to penetrate through an entire building, and is usable on the other side.
Basically, whereas Wi-Fi can punch through about one wall before fading out, the UHF packet radio link can punch through something like 10 walls before fading out.
|Points with confirmed coverage back to my hotel room. Actual coverage is somewhat better, but the collection tool needs tweaking to show spots with good link below 10dB.|