This signal type (Amplitude Modulation) is what is used by the Petsafe systems. (Inc Freedom Fence).

Cost effectiveness - you won't beat this brand.

You may however have some compatibility issues with some brands of robotic mowers. That said, Petsafe is incredibly cost effective and available on the retail market.

They used to have a professional range available through the dealerships (such as Freedom Fence and Goore), this is no longer the case and anything you want by Petsafe is available direct from them or other retailers (and much cheaper).

Buy it from a dealership and your pay more unnecessarily!

If you hunt about online there are some bargains to be had occasionally. Petsafe have been selling retail for so many years and are very established.

Don't be put off by it being cheaper - its very good kit.