HFC Cable Degradation

As an Optus internet broadband cable user can anyone explain how the cable which is up in the air at my address has become degraded which was the NBN’s excuse to delay further installations on HFC. Many of my neighbors still have pay tv through it as well as the internet.all working fine till they get flicked soon to the inferior satelite which does not work very well in bad weather, I get excellent around 100mb/sec.d/l according to the optus speed test so am not in a hurry to get slower NBN…
Surely this compulsory migration will free up an awful lot of bandwidth which must help the situation. I cannot get my head round how this airborne cable which I think is multiple co axial core can be deteriated against the copper cables harsh environment in the ground going through water logged pits and ducts.


Copper oxidises due to oxygen around the copper. This happens because during manufacture the copper is exposed to the air. Then you also have the joints exposed at various points such as where the cable is connected to the house (both at the street cable and the household box). Many of the street connections are also exposed to air and they also use hardware not suited to the way the digital signals are transmitted in the HFC system (DOCSIS 3.1) which will support gigabit speeds compared to the current Optus and Telstra systems.

When Mr Turnbull decided to use HFC he thought that he could just take the old infrastructure and use it, but in particular the Optus Cable network was so under-maintained it cost millions more just to do the Redcliffe Qld connection. During this NBNCo realised it had a huge problem on it’s hands and so at the moment a lot of HFC work is on hold while they try to fix the problems. This also prompted a change to how they connect houses and many new contracts are for supply of FTTC rather than FTTN & HFC. Old contracts are still making contractors of the NBNCo to install HFC & FTTN in the older planned areas.

So partly in answer to your query about your house, it is the overall state of the Optus network that is not good and your particular area may get great service but others don’t. Because of this if your area is a newer contract for connection, NBNCo rather than dealing with possible/probable issues (we are talking money cost to them not technical) will likely take the easier road of supplying Satellite or maybe if politically pressed FTTC regardless of your satisfaction with your current service. They bought it so they do what they want with it really.

Coax Cable is not multicore in the sense that you all do not join onto your own separate wire, you all share the same piece of copper wiring. The central internal piece almost always is a single copper wire which is then surrounded by an insulating layer and then another layer of copper (think of that one like a foil sheet) that surrounds that insulating layer. From a Broadband explanation “A coaxial cable is just a copper cable with two conductive layers – a core copper wire and a surrounding copper sheath, with the two separated by an insulating layer. These cables are designed and used exclusively to carry radio signals such as internet and cable TV, meaning there’s no risk of interference from phone signals” The cables you see in the street are just built with extra protection to avoid issues like abrasion, stretching, & temperature fluctuations and so are thicker than when you look at a household type coax cable eg for an antenna. What they do on the street is connect your aerial cable into a box that has fittings that allow joining your cable to the internal copper of the street cable.

Certainly many pits can be and are waterlogged and this does affect connections all around Australia when the waterproofing fails, but if it doesn’t fail it is quite water resistant. In many places coax cable is also run underground and again if the line is sealed well, water is not a big issue. But the oxidisation of the line continues and over time becomes very apparent. Also while standing water is not always a big issue moisture from condensation, rain, sleet, & melting hail & snow all manage to penetrate to some larger or smaller degree whether aerial or in the ground and this exacerbates the corrosion of the copper in particular where it joins another metal fitting or wire (this is for both coax and phone lines).