Slice meat into long strips, 1 inch wide and 1/8 inch thick. In a large releasable plastic bag, combine soy sauce, Worcestershire sauce, liquid smoke, ketchup, pepper, garlic powder, onion salt and salt. Place meat in, and close bag. Refrigerate overnight. Knead occasionally, to evenly distribute marinade.
Preheat oven to 160 degrees F (70 degrees C). Place a pan on the bottom of oven to catch drips, or line with aluminum foil.
Place meat strips on a rack so that they do not touch each other, and dehydrate for 6 to 8 hours in the oven, or until desired consistency is achieved.