I began using Roku on TVs in home and 1 TV is having issues with connectivity. Am I able to use another Cable/Modem at the TV location for a stroger signal? I have an extender in place but thats not cutting it.
Most systems will not allow two modems to be used at one address. It's best to call in to see what the local policy is. Even if they do allow it you will need to pay for two accounts (twice what you are paying for HSI now).
Powerline ethernet or MoCA adapters may be an option for you. Google for more info.