I guess you didn't read the topic at all.
Reset router
This has always been and will always be the first thing I do. Furthermore, I have a modem in bridge mode with my PC directly connected and then a separate wireless router for the mobile devices. Resetting either and/or both will not fix the issue because the issue has nothing to do with my internal network.
Update wireless driver
Telstra updates the modem automatically. The router was updated not too long ago, and no updates have come out since. Even then, updates have nothing to do with a 57dBmV power-draw.
Reset router again
If it still doesnt work reset the router once again
Next reset the router
Still failing? Reset your router
Don't be stupid.
STILL failing? Call your ISP and let them replace the router (if they gave you one)
Firstly, dude, router =/= modem. Modem is what connects to the internet, router is what allows you to ROUTE the network to multiple devices, including both wireless and wired. Nowadays most modems have an inbuilt router, but it's generally a good idea to buy a stronger, separate router to improve range and frequency issues that the cheap/free ISP modem-routers have.
This is the third modem and my second external router. As I've said, in the OP and other posts, the evidence concludes the issue with the external network, likely the taps and/or isolator.
My modem is reporting a 57.0dBmV, which is beyond specification. It means that my modem is having to scream over the cables because it's having difficulty hearing what the ISP is sending our way. The downstream values are golden; very awesome SNR ratio which means the cable quality is good, and the power draw on the downstream is around 0.0 which means we're not having issues pulling stuff from the Internet. This is an issue with my ISP's external equipment malfunctioning, likely due to corrosion.
If you had of read my post above yours, I said I contacted the ISP tonight and they've already started work on what they think is the problem.
If all else fails get cable. If its possible.
I am on cable. 500GB download cap, and I get about 8Mb/s down, 2Mb/s up. That's pretty decent for Australia.