independent cable installers / technical experts: anyone know some?

hmm, ok.  Not sure electricians are equipped for that, but I know a place where they all hang out, so I'll ask.  We used to have an independent cable installer in town, but he retired 😞

I'm not recommending an electrician; however, an electrician could recommend a local contractor to run your coax.  If you're to subscribe to any broadband service, you'll need to replace your RG59 with RG6.

RG59 is old and only good for ham radio and low-def CCTV cameras nowadays.

Just because someone retires, it doesn't mean they won't do it (wink).

Let me add this:  if you're to subscribe to gigabit service and Cox can run fiber-optic cable to your HOUSE, you won't even need coaxial cable at all.

Cox will need to come to your house and install all terminals and run a portion of fiber to your ONT (modem).

Not sure if Cox runs fiber in our area.  Practically every house in this neighborhood is likely run with RG59 in the walls, as most are from the 50's to 80's.  We have no problem with download speeds, as a recent test of a new cable modem showed we were capable of 400mBp, streaming works fine, etc.  The problem is we may have some frayed lines in the walls, very looooonnnnng home-runs that couldn't be redone without ripping out all our drywall.  If they had to be replaced, running cable all over the outside of the house isn't really what would be the first choice, you know?

If the older cables are damaged, and are sending ingress back into the system, it's likely Cox will want to find a way to stop that.  What's a drag is none of this is any problem for the technology it was meant for, but instead a problem for technology that wasn't even invented.  I'd have to think the average customer wouldn't be happy paying to re-run internal house wiring because a monopoly can't handle bandwidth in it's nodes (the problem here, as Cox hasn't split up our neighbor hood into smaller, 50-home nodes: ours is still part of a 1969 500 home system.  Funny that THEY aren't upgrading, but they may demand we do.

hmm...

You could probably get 1 Gbps speed through an RG59 cable but due to the inferior shielding...if any...of RG59, most of the throughput would be noise and interference.  Also, RG59 cannot transmit at the higher frequencies required for digital signals nowadays.  You could connect a DOCSIS 3.1 to your RG59 but you won't get a clean signal.

You assume the cable is frayed but it's just the construction of the cable.  Swap it out.  If your entire neighborhood has RG59, perhaps you could negotiate a deal for a bulk contract.

RG59 was great for analog TV but those days are gone.  Just like electrical wiring, pipes and windows...stuff evolves.