Home wifi and what the hell are my walls made of?

I live in a small house by UK standards, most Americans have garden sheds larger, yet getting wifi to work has always been a challenge.

Domestic wifi can be difficult, partly because all your neighbours have it too. Chances are in many homes you can pick up dozens of 2.4GHz wifi networks, which means finding a free channel is pretty much impossible.

It isn’t much better on the 5GHz band. Quite a few ISPs configure their supplied routers 802.11ac routers to use 80MHz channels. They don’t use DFS channels either. Because quite a few of the cheaper 802.11ac routers out there only support the first four channels of 5GHz, you’re out of luck when it comes to finding a free channel.

I have a different problem. My tiny house is a terrace, built in the 1930s. It may be small, and built cheap (a single window spans two rooms upstairs at the front) but boy is it solid. Exterior walls have a cavity with brick on the outside and concrete block inside. The few occasions I’ve had to drill a hole, it’s been very hard work. The non-structural interior partition wall between the two front bedrooms is concrete block, even though it’s just supported by wooden joists.

My ISP supplied router was hopeless. Only really worked in one room of the house. I replaced this with a Draytek unit. As an aside, I really like Draytek routers for domestic or other soho uses. They tend to feel a bit dated now, but my experience is they’re rock solid and work reliably.

However wifi was still useless. In the end I’ve used a Ubiquiti AC-LR AP for our home wifi. Coverage is far superior from the same location (reaches the all important seat in the bathroom), it’s faster and it supports DFS channels so I can keep away from the neighbours.

But, despite this I was having trouble with my desktop PC. This is in the room next to the AP. Draw a straight line between them and it’s less than five metres, yet signal strength is poor and the connection unreliable.

I spent a while messing about with the cheap wifi adapter in the desktop before attention turned to that wall. That single block thickness wall. That partition between two rooms.

Rudimentary measurements show 18dB drop at 2.4GHz and 25dB at 5GHz. This is why I can’t get a decent signal at the far side of the room, even though it’s tiny.

The plus side of this is I don’t have a big problem with neighbouring wifi networks filling my channel space. I appear to live in a tiny faraday cage that’s particularly unfriendly towards 5GHz signals.

The answer will be to relocate the AP to somewhere with less of that special 1930s lead brick between it and my desktop. Sometime soon I’ll do some better testing using the Ekahau sidekick and write up what I find.

1 Comment Home wifi and what the hell are my walls made of?

  1. Pingback: Wall attenuation – video | Wifizoo

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