Possible to build a transmitter for a “invisible fence” type wireless pet containment system?

Question by twobearcatz: Possible to build a transmitter for a “invisible fence” type wireless pet containment system?
I have a model made by Innotek that I use to keep my cat IN the house. These things are expensive, and I don’t think the model carries an optional remote. You can get optional “disc” transmitters, but they are “always on” perimeter control type units. Is it possible to build such a remote control? I would imagine this would be similar to building a transmitter for something like a garage door, etc. Thank for any help!

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