Between the years 1979-81, approx 8:30-10:00pm (fully dark out) warmer months, summer. I was between the ages of 8-10 yrs old, may have been younger. I was standing at my back door calling for my cat to come in as I did every night. Suddenly I noticed a large black disk the size of a stop sign at arms length approx the height of a tall radio tower floatng slowly from the left rear of my yard. It may have made noise, if it did, it was not loud. It moved over my house diagnolly to leave the front right side (facing home). I ran from my back door to the front door outside holding the hand rail as I looked up at this massive disc. I was young, I did not know about UFOs. The bottom didn't appear to be smooth, it looked like it had sections that were raised, with sharp edges? Not excessively, enough to see a difference. I was awed, amazed. And I watched as it moved slowly across the sky. The sky was clear, because it was dark against the craft. I watched it till I could not see it anymore due to homes or trees. I must have gone in at that point because I was not allowed out front by myself. I know what I saw, but I don't know what it was. It has stayed with me all these yrs, clear in my head. I recently was out walking my dog and stopped to look at a radio towers height, and figured what I saw that night was as high or a little higher. And I think it must have been as big or bigger than a stop sign held at arms length. I want to know if anyone else saw anything? I want to know and understand what it was I saw. I want answers. I would love for people to take me seriously when I talk about my experiences. I am a college graduate, single mom of two teenagers. I work full time for a local builder. I am a skeptical believer in Ufology. I have followed the subject for at least 25 yrs, or longer. I am a current member of MUFON. Thank you for your time.