Why does my TV have the hiccups since getting my cable service rewired?

In March I signed up to get digital phone service from my cable TV provider. The technician had to re-wire the house because he said that the wires were so old (put in the in 1970's) they couldn't handle the added phone service. Since then, my TV has had the "hiccups." I get the signal clear enough but every 3 to 5 minutes, the TV screen goes gray showing the words "unusable signal" for about 3 to 5 seconds and then the picture and audio return to normal. It's not any regular interruption like I could time with a stopwatch. I don't have a "box" from the cable company - the coax cable comes in through a hole in the wall and is attached to my VCR player, then another coax cable goes from the VCR to my RCA 19" TV. The TV is about 15 years old and the VCR maybe a little older (and it was recently repaired because the picture was "rolling"). It also happens when I'm watching a tape through the VCR, but even more frequently. Any idea what's going on?