76.605(a)(5)(iii)

Fact

(5) The visual signal level on each channel, as measured at the end of a 30 meter cable drop that is connected to the subscriber tap, shall not vary more than 8 decibels within any six-month interval which must include four tests performed in six-hour increments during a 24-hour period in July or August and during a 24-hour period in January or February, and shall be maintained within:

(iii) A maximum level such that signal degradation due to overload in the subscriber's receiver or terminal does not occur.

Myths

"Any old signal will do..."
First of all you have to have at least 0dBmV at the Sub's terminal, 76.605(a)(4) has shown us that. The main problem is subscribers using 75 to 300 ohm transformers that are leaking like a big dog.
The television's manufacturer would be a good source for maximum RF input information.

Measurements

There are several types of meters on the market today to make these types of
measurements. 76.609(a)provides some suggestions on how to perform
other tests and 76.601(a)(1)provides test point and data collection information.