For better, or for worse in the winter of 2013/14 the old school Ortovox F1 was discontinued. While the F1 is a tried and true analog single antenna avalanche beacon, all modern beacons are better in nearly ever way. If you have owned an F1 in the past and want something similar because there is nothing quite like it. The closest thing is the Pieps Freeride, a single antenna all digital beacon. Function wise the Freeride is like an automatic car version of the F1 because you don't have to dial it down, but if you were really stoked on the F1 for its range and simplicity you likely won't be stoked on the Pieps Freeride. Instead look at the Backcountry Access Tracker 2, the Ortovox Zoom+ or the Ortovox 3+ which are all relatively simple beacons, that will be much easier to use and significantly faster during rescues.
Most people today don't know why it's called the F1. It came after the Ortovox F2, so why did the F2 come first? Well there used to be two frequencies that beacons used, one in Europe and one in the USA, but not everyone in either region always had beacons with the same frequency. So the F2 was the first beacon to accommodate both. Then users around the world settled on 457,000mz. They then updated the F2 to the F1 (Or one frequency) to a similar model that is sold today. It works but you really need to know what you are doing. We don't recommend it unless you have a ton of experience and it's really that important to save a little money. For just a little more you can get the Ortovox 3+ or the Backcountry Access Tracker 2, which have three antennae and are much easier to use.