I’m new to the GoTenna Mesh community and recently picked up two new GoTenna Mesh devices in Seattle. Today I tested them expecting to be able to easily hop/relay a message from a highrise in downtown Seattle to my residence in NE Seattle 7 miles away. Based on the number of powered relay nodes and the Seattle Super RN nearby, I was sure it would work well. The test was a partial failure from the 47 floor of my office tower. I was not able to get a network relay message sent through without using SMS Network Relay. I expect the message might have gone through if enough mobile nodes were turned on and connected but at noon today in downtown Seattle, no such luck.
I’m an Architect and I had a hunch, so I did some research and wanted to let the Mesh users out there that modern office buildings have Low-E (Emissivity) glass that blocks radio signals from a GoTenna mesh. Low E glass has metallic film on it to limit thermal transmission through the glass. This also blocks radio signals. The building I’m in has the type of high performance low-E glass that can block RF by a factor of 10,000. “The reduction of radio frequency signal intensity after passing through a material is called attenuation, which is usually expressed in units called decibels (dBs). A decibel is a logarithmic unit, so as examples, a 10 dB attenuation is a reduction by a factor of 10, a 20 dB attenuation is a reduction by a factor of 100, and a 40 dB attenuation is a reduction by a factor of 10,000.” More info on this subject can be read here. https://www.vitroglazings.com/media/1l1k3zcc/vitro-td-151.pdf
Basically, If your building was build after the 90’s in Seattle, you can expect it has Low-E glass that will significantly reduce the ability for your GoTenna to send and receive messages through the glass.
I’m hoping this info will help users understand why their GoTenna might not work effectively inside a highrise. Line of site will only effectively work outside the building skin. Get those powered nodes up on the roof or outside the glass if you can! I’ll leave my GoTenna Mesh’s on for you all. Thanks for listening.
Good observations and you even have the solution (in many cases). A roof-mounted node will work, depending on how many floors are involved.
Sounds like your building is, ahem, on the taller side, so effectiveness will depend on how close the 47th is to the roof, if access is permissible. A good selling point on getting some support for such access is the fact that it’s a good backup to building systems in an emergency if implemented with an eye toward such needs.
Low-E glass is becoming fairly ubiquitous in commercial construction now even in the Midwest. A local; grocery store built less than 5 years ago has it. I’ve been in meetings in it’s lounge area on the second floor and tried to reach my truck sitting maybe 50 m away in the lot. No go. The glass is very effective in screening out signals.
Very useful info.
Thanks Mike,
I appreciate the response and insights. I’ll see what I can do to get a node on the roof of the Tower.
Thanks, very useful info.
Mark
That’s what happened on 9-11-2001 in NYC to the firefighters inside burning buildings. The RF wouldn’t go thru the windows.
Nope, different radios, different frequencies. Plus the use of such glass was just getting started at the turn of the century and the WTC was built in the early 70s, so I doubt that low E glass was even in place there. There are some sunblock coatings that were a factor prior to low E glass, but not sure that was a factor at WTC.