Kees, the Kenwood TH-D72A does SO-50; very well. I know it is expensive, but you get what you pay for. It will also send and receive packets to and from the birds, which I am learning to do. You have a great signal on the birds. If you ever get a D72, I will help you set it up and learn to operate it. I love mine. Brad Smith KC9UQR Sent from Brad’s iPad