How likely is it that OTA 8vsb will interfere with QAM256?

I am wondering about any good cheap way to "Faraday cage" a TV for troubleshooting.

The TV was receiving Clear QAM on Hyperband Ch. 84 (583 MHz +/-). This consisted of 1 channel of 1080i and 8 channels of 480i or less. Last week the audio and video stopped, so it shows a blue screen, but when re-scanning the TV it is still receiving PSIP data, so the channels are still there. Other TVs receive the cable TV signal normally.

My theory is that OTA RF channel 33 (585 MHz) is interfering with the cable signal on this TV. The Ch. 33 tower is 0.6 miles away and line-of-sight from a window behind the TV. So the 585 MHz OTA signal is very strong, although I haven't got a meter to check it.

No idea why it started last week. TV is an Olevia, so they're no help.