I transmitted this way using a raspberry pi and a basic filter and antenna and was heard one day in New Zealand from Ohio. https://github.com/JamesP6000/WsprryPi
Pretty much that project, a Raspberry Pi, a ham radio license, a small filter board from QRP Labs, an MFJ antenna tuner, and then a long wire over the roof of a single story home. No other amplifier. The New Zealand reception was just once. I did somewhat more often get heard in Germany or Brazil, and quite regularly east of the Mississippi and west of the Appalachians, but never closer than about 50 miles, that is, no one ever heard me in town. This was across like 40 meters and 10 meters I think about seven or eight years ago. I ran the beacon all the time for a couple of years.
The ideal range/speed is somewhere between 100 and 1000MHz, ideally you would want that entire range.
But how do you build a band pass filter that can cover the entire range?!