How can I change a dozen TV's all to the same station with one button press?

If the tvs are all the same brand and model, they would all respond similarly to any general purpose replacement remote.

I'd consult with firms that do this for a living.

Yes HDMI splitter, then you plug into the source input and split it to all TVs. If you are buying that many TVs, you might want to check out this discount store called Best deal in town they sell in bulk at good prices http://bestdealaz.com/

it is a good project for an electronics student .... try to find someone in the university ..

he/she converts infra-red commend signal into an rf one ....builds 12 rf to infra-red converters ...installs in front of each tv ....so with a remote you may do a commend on all of them at the same time ..

tv remote signal26→gets modulated on an rf carrer→ demodules the rf signal

You'd use a single input device - cable or satellite box - and then connect this to all 12 TVs.

You'll need a powered splitter to ensure that you don't lose signal quality.

Once you have all 12 TVs connected, and set to the proper input, use the cable/satellite remote to change the channel. Since this box is connected to all 12 TVs they'll all show the same thing simultaneously.

The best method would be feeding all of them from one cable or satellite box.

You would need a distribution amplifier with at least 12 outputs to connect between the box and the TVs.

Pretty simple, huh?

Otherwise, you would need a remote extender and 12 of a thing called an "IR blaster".

This may be cheaper, but it's also less reliable and rather messy.

My advice: Go for the first method.

While you could wire them all into one cable box with an HDMI screen splitter, you wouldn't be able to ever put the TV's on different channels. Otherwise you would have to install enough IR repeaters to be able to transmit to all the TV's, but it still could be an issue if they require different remotes for the TV's. If you have different remotes you would have to get a good programmable one and program the remote to send the numeric channel IR signal for all the different tv's into a repeater for each button press. It's really a job for a professional home theater installer, since if you don't buy the right equipment for the install it can turn into a big mess. Wireless IR repeaters won't be reliable in that type of environment so you would have to run wire to each tv.