the wiki and the history of postings in this forum is your best source to read up.... there have been many changes over time, and there continue to be, so keep in mind as you read that it has been a fluid process...
as for the bean, that is a "sending" device that works to broadcast frqs from a frequency generator like an f165... the f165 can work with a variety of devices like plasma tubes, the 'bean' or just as a contact device with footpads and hand holds...