A few years back, my wife and I bought a house on 7 acres of wooded property on the edge of a hill, which she affectionately calls our “treehouse”. We can often see deer when we look uphill out our bedroom window, and we’re entertained by horses, donkeys, and bulls when looking downhill out our bathroom window while brushing our teeth.
Living among the woodland creatures is not without its downfalls though. The electric utility runs its lines though this same forest, which for some reason has an incredible number of dead and dying trees (I’m no botanist, but I think it’s from the handiwork of the emerald ash borer). In any case, there are many days when a slight breeze can lead to a power outage.
I addressed the situation with an approach similar to what I’d follow in my day job – though with a smaller budget:
- Installed a UPS to allow cable modem, router, switch, and Wi-Fi APs to survive brief power outages (at current battery health, the gear will stay online for ˜15 to 20 minutes)
- Got a generator capable of producing 240 V output, directly wired into electrical panel, to support critical loads during longer power outages
The cable ISP, though, doesn’t seem to have taken the same power backup precautions. I’d understand if their outages were caused by a tree falling on and snapping their aerial lines – that’s a layer 1 reality that requires a layer 1 solution, which takes time. However, their outages always match those of the electrical utility. I know where their ‘magical fiber to coax gear’ (I’m not a DOCSIS engineer either) that serves my house is located, so I know when it loses power too.
As someone who works from home most of the time, during one recent power outage I decided this situation was unnacceptable and must be remedied – I needed a backup ISP. But quick research showed few available options:
- No other cable or fiber ISPs serve my address – not even DSL
- Starlink was too expensive for a backup solution
- My house has marginal coverage from the big three US mobile networks, but none of them would offer me FWA – Fixed Wireless Access – at my address
I’d dabbled with cellular modems both in my day job as well as in conversations with folks in the WLPC community, and figured this would be an opportunity to solve a problem and learn a couple things while I was at it – thus began my evil plan for a homemade cellular internet backup solution!
I decided the end solution must meet the following requirements:
- have the flexibility to support any MNO (Mobile Network Operator) or MVNO (Mobile Virtual Network Operator) whose signal reached my house; contracts or carrier lock-in was not an option
- be robust enough to survive outdoors where the wireless signals are unimpeded by residential wall materials
- it’s possible to extend cellular antennas from inside to outside of course, but the coax needed to sustain minimal loss over 10 – 15 M at the frequencies in question gets expensive quickly
- be powered only by PoE
- support seamless failover from my cable ISP to cellular, and then back
- be a fun project and a source of professional development
- (not gonna lie – I also needed some blog entries for my CWNE app!)
Come back soon for Part II – The Build!
CablingOptional 