Charlotte.
Although a good ground can sometimes lower the noise slightly it appears you are getting noise from a source such as power lines, appliances, or electronics near your antenna. It is a lot of trouble, but the first step would be to use a receiver or portable transceiver to check the TV, computer, monitor, lights and any other electronic sources or disconnecting them one at a time. I use an H/T on 135.9 in AM mode; however a SW radio and checking different bands of interest in the AM mode will work well. When near a noise source, remove the antenna for pin pointing the problem. I do not know what your laws are regarding RFI, however locating sources such as bad power line transformers and insulators, street lamps, can be done the same way. I have had good luck in finding power line noise and having the power company fix the problem.
73, de Lindy