I did something similar in an old house - I used a signal amplifier with baluns to boost my cable signal through the old 300 ohm wire that ran up the wall, through the attic and eventually into our bedroom. It did boost the cable signal so that I could watch TV there - but the mis-match caused some harmonics that ended up interfering with communications at the local airport. We got a friendly visitor who asked us to cease and we disconnected the amplifier. I ended up having to fish 75 ohm cable to resolve the issue.
I'm a fairly active ham radio operator and have a neighbor who screamed bloody murder everytime I went on the air. He said I interfered with EVERY TV channel on his cable. The guy was a retired engineer who said I was operating with too much power, etc. Even if I operated with 10 watts, on any ham frequency, I got a phone call to turn it off!!! He would not let me see his "installation" so I might help clear up his problem. Funny thing, if I was transmitting with 500 watts, I did not bother any TVs in my house, which were also on cable. I told him to call the cable company because the problem was not being caused by me. A few days later, the cable guys parked in front of my house and wanted me to transmit with full power on various frequencies while they monitored the signals in their truck. After about an hour of this, they told me my transmissions were "Clean". They then told me that the guy next door who complained, had daisy-chained about three TVs in various rooms in his house to the cable system with 300 ohm twinlead!!!! I hoped they charged him to recable his house. For 10 years now, I've had no complaints from him!
I had a similar issue with the neighbor on the other side...WITH HIS TELEPHONES! I went over to look at his phones... AGAIN, another situation where he daisy-chained Four phones together with zipcord. The cords were running all over the house, under carpet, etc. A few torroids strategically placed fixed that problem....
Many years ago I had a similar problem with a guy who saw my ham antenna and complained often that I was interfering with his TV.
I tried cooperating with him even though many of his complaints occurred when I wasn't on the air.
One day while driving up to my house I saw him knocking on my door to complain about his TV interference.
I got out of my car and smiled and asked "How are you doing today?"
Needless to say that was the last time he ever complained to me about his TV problems.