Amateur TV is an extension of amateur radio but as well as talking and computer linking over the air, we send each other television pictures as well.
It must be stressed at this point that in order to broadcast any ATV at all you must hold a license to transmit. The rules and regulations on getting hold of a license and what you can use it for varies from one country to another. A good starting place is your countries Post Office. In the UK you can get more information from OFCOM and the national radio society RSGB. You don't normally need a license or permission to receive ATV signals.
As with most hobbies, you can get on the air at very little cost if you are prepared to spend time building your own equipment. Home construction is far more satisfying than buying everything ready made. Of course, there is no upper limit on what you can spend but money doesn't equate to quality and it certainly doesn't compensate for the thrill of doing something for nothing or being able to demonstrate what you have made with your own hands.
What do I need to see amateur TV on my normal television?
Well, the signal from an ATV station is very similar to a normal broadcast signal, the only reason an ordinary TV can't pick it up (at least in most countries) is they are not in the same frequency bands as commercial broadcasts. They are actually on a whole range of channels but none coincide with normal TV. Some extra equipment is needed.
You can of course built an ATV receiver from scratch, many people have done so, but converting existing equipment to extend it's coverage to the ATV channels is generally an easier and cheaper solution.
Probably the easiest way to get started is to make a simple change to an analogue satellite receiver. In a normal domestic installation some electronics sits in the LNB (the thing at the end of the arm that points into the satellite dish) and some of it is indoors in the little box under the TV set. If we ignore everything from the indoor box up to and including the dish, we have a ready made ATV receiver that covers the 24cm band.