A sincere question...
Why do you let your dog outside roam unattended?
At the end of the day, none of us can control our dogs when they are outside left attendended (unless they are in an enclosed area such as a fence), which is why I ask.
We let our Weimaraner have free run. We're on 62 acres, house close to the center of the property. She doesn't ever go more than 100 yards or so from the house, unless we are walking with her. If she's out of sight, in one of the tree lines, one call of her name and she comes bounding back immediately. It's been our experience with this breed that females stay close to their humans, and this one is no different. It's also her job to keep an eye on the free ranging chickens, chase off predatory birds, let the deer know the garden belongs to her, and to bark when someone is coming down the driveway. She's an excellent watch dog. No problem not having a fence. She's mentally tethered to the house and the family. More reliable than a fence.