Due to multiple kills on our phones and computer equipment by lightning over the years we converted our local area network (LAN) to WiFi back when it first came out. I had worried that the stone and concrete of the tiny cottage would block the networking signal. All the books and articles I’ve read say that is the case.
With this in mind I very carefully designed the new house to have lines of sight for the WiFi networking and cordless phones. Even though it is a tiny cottage, just 252 sq-ft, I wanted to be sure that we would get good strong signals. It would be a shame to have all that thermal mass and beautiful rock blocking access to the universe via the straw of my choice – the internet. To this end the place for the WiFi base station is designed to be near the front of the middle of the house so that it can see and be seen by each desk space. So much for theory.
Today Ben and I took our computers and the Airport Base Station (WiFi for Macintosh) up to the cottage and then did a variety of actual tests now that the walls are actually in place for the most part. I wanted to see how much interference we would get from the steel reinforcing rebar, diamond lath (steel), 661010 Welded Wire Mesh (WWM) and simple concrete with PVA fibers. We tested through a single partition wall (4″ core filled pva concrete with rebar), through two partition walls, 3 partition walls and even 3 partition walls plus one full size block wall (8″ core filled pva concrete with rebar). I also tested through the glass of the windows and then taking my computer up to 100′ away from the house in a line of sight through the window and also testing through the open doorway. I tested through the concrete back wall plus three partition block walls and 100′ away outdoors for a very tough test of 100′ of distance including 20″ of concrete block with PVA concrete poured steel reinforced cores. I even tested the signal through the roof which is a barrel vault of steel diamond lath and 1.5″ of PVA concrete. See the floor plan for a general idea of the cottage layout.
All this was for naught – Turns out concrete is virtually transparent to wireless communications (WiFi). Even the roof with all that steel in it had no faraday cage effect – probably not grounded well enough. We had no noticeable difference in signal strength in any of the tests until I got a long ways out. Any further and I would have dropped off the cliff. Viewing through the open door, a window, and multiple layers of concrete wall all gave the same results. This is ironic because the sheetrock, bookshelves, siding and other assorted things in our existing house block the WiFi quite strongly. One more little benefit of moving into the new cottage will be better networking.
The EMP from these strikes can do nasty things to our phone wires but it has never bothered the WiFi. Why do we get so much lightning? Probably because we’re up high. Fortunately we’re not on top of the ridge, where we often see repeated lightning strikes – yes, lightning does hit the same spot twice, thrice and even eight or nine times in a row. Yowsa! Quite the fireworks! You see, there is a big vein of copper and maybe iron as well in our mountain. It runs south to the Elizabeth Mine and probably to the north as well. We’re along a north-south geological fold in the mountains at the height of the watershed. All the water on our land runs to the east towards the Connecticut River. All the water to our west runs to Lake Champlain.
We can even connect to the internet from the great stone picnic table by the upper pond. Personally, I would rather be swimming!
Saturday Outdoors: 77°F/55°F Massive lightning storm, 4″ Rain
Farm House: 76°F/56°F
Tiny Cottage: 71°F/63°F
Sunday Outdoors: 80°F/56°F Overcast
Farm House: 75°F/57°F
Tiny Cottage: 72°F/63°F WiFi testing