The Dirty Secret of Coaxial Broadband

The US has clearly pinned our hopes for providing modern broadband on the big cable companies. At the end of 2019, the big cable companies had almost 68 million customers compared to 33 million for the big telcos. Any discussion of broadband in urban markets is mostly a discussion of big cable company broadband. Cable companies will continue to grow market dominance as urban DSL customers continue to migrate to cable modem. In 2019 the big cable companies added 3.1 million customers while the telcos lost over 600,000 customers.

The big cable companies have all advertised to their customers that they had upgraded to the latest technology in DOCSIS 3.1 and can now provide gigabit broadband – for an expensive price in most markets set well over $100 per month.

It’s easy to think of urban cable systems as up-to-date and high tech and ready and able to deliver fast broadband speeds. While this is true in some cities and in some neighborhoods, the dirty secret of the cable industry is that their networks are not all up to snuff. Everybody is aware of the aging problems that have plagued the telephone copper network – but it’s rare to hear somebody talking about the aging of the cable company copper networks.

Most of the cable networks were built in the 1970s, with some even a little older. Just like with telephone copper networks the coaxial networks are getting old and a network built around 1970 is now fifty years old.

Cable coaxial networks suffer more from deterioration than do telephone copper networks. The copper wires in a coaxial system are much larger and the wires hanging on poles act like a giant antenna that can receive a range of different frequencies. Any physical opening into the wire through a splice point or from aging creates a new ingress point for external frequencies – and that equates to noise on the coaxial network. Increased noise translates directly to decreased performance of the network. The capacity of the older coaxial networks is significantly lower than when the networks were first constructed.

Another issue with coaxial networks is that the type of coaxial cable used has changed over time and some of the coax used in the early networks can’t handle the capacity needed today. Some older coax has been replaced in urban networks, but not all. Coaxial networks in smaller towns still can contain a lot of older-generation coaxial cables.

These issues mean that coaxial networks don’t always perform as well as is touted by the cable companies. I can use the network in my city of Asheville NC as an example. Charter announced nationally that when it upgraded to DOCSIS 3.1 that it had a goal of raising broadband speeds everywhere to 200 Mbps. My speed at the modem is 135 Mbps. I’m not complaining about my speed and I’m glad they increased my speed, but there must be issues in the local network that stopped Charter from achieving its 200 Mbps goal.

We undertake surveys and citywide speed tests across the country and we often see that the performance of coaxial networks varies by neighborhood. We’ve seen neighborhoods where there are more outages, more variance in download speeds, and overall slower speeds than the rest of the city. These problems are almost certainly due to differences within a city of the quality of the coaxial network.

Cable companies could bring older neighborhoods up to snuff, but such upgrades are expensive. It might mean replacing a lot of drops and any runs of older coaxial cable. It might mean replacing or re-spacing amplifiers. It often means replacing all of the power taps (the devices that connect homes to the distribution cables). The upgrading effort is labor-intensive, and that means costly.

I think this means that many cities will never see another unilateral increase in broadband speeds unless the cable companies first make big investments. The cable companies have increased speeds every few years since 2000 to keep ahead of the telcos and to make customers happier with their service. I fear that since cable companies are becoming de facto monopolies in most cities that they have lost the incentive to get faster if that means spending money. The coaxial networks and speeds that we have in place today might be what we still have a decade from now, only with coaxial networks that are another ten years older.