On October 31 we had Industrial Communications and PME on-site at the Tiverton tower and the Omni Providence Hotel to install our new SAF Tehnika CFIP Phoenix C 11GHz Studio/Transmitter Link (STL) wireless ethernet radio. It’s kind of the equivalent of a 20 mile long ethernet cable without the hassle of a physical cable being strung through Narragansett Bay. 🙂

This wireless link, for the first time, brings telco-independent connectivity to the Tiverton site. We control the entire system, from the studios in 1 Union Station to the transmitter shelter at the base of the Tiverton tower. There’s no issues dealing with Verizon killing off your service because it’s old and “legacy” and forcing you to fiber is more lucrative for them. There’s no way a tree can fall on a telephone pole in a storm. And no way a construction vehicle could tear up a fiberoptic cable conduit (aka “backhoe fade”). It’s all on us, which does mean more work for your Intrepid Engineer but at least it means we can put as much redundancy and quality into the system as we need.

There is one caveat here: since it’s a 20-mile-long wireless path, there is the risk of “rain fade” (or snow fade). Whenever it rains or snows, the drops of water in the air refract and reflect wireless signals to a certain degree. That means less signal gets into the dish. And if the rain/snow is heavy enough, that could mean you lose the connection. In theory, our “link budget” means this won’t be a problem. The radios lose connection at about -75 to -80dBm. Our target signal received is -47dBm. (these are negative numbers, so lower is better) We actually managed to get to about -42dBm, so we’re doing a little better than expected. But this means we have 33dBm of fade margin. That’s pretty good; not quite enough to get to 99.999% reliability, aka “five nines“, but we’re close. I think we’re estimated at 99.993%. That sounds like a trivial difference, but five nines = 5.26 minutes per year (or 6 seconds per week) that the link is down. 99.993% is about 45 minutes a year or 50 seconds a week. Obviously I’d prefer no downtime at all but I can live with that. Heck, we probably have 50 seconds of dead air a week just from normal flubs and hiccups lasting a few seconds at a time. The adventure of live radio!

I had the tower climbers on the Tiverton end take some nice pics of the setup and of the surrounding countryside. At 340ft up you get a nice view of the fall foliage!