Tom wrote about amateur radio licensing:
Getting a license:
You need each lower level first before you can get the next one. Start
with Technician, then if you want to use lower frequencies/other
modes, get the General Class license.
Note that in the US, the exam fee covers any number of exams taken in
the same session. In other words, once you take the Technician exam,
and pass it, you can try to take the General exam immediately at no
extra charge, and if you pass that, you can try the Amateur Extra exam.
There is no penalty for failing an exam, so you may as well try to get
as far as you can at one sitting.
There are lots of online resources to help with studying, so you don't
even have to buy a study manual. I bought study manuals, but barely
cracked them open. I did practice tests online. The Technician class
was a piece of cake. I had to study a little bit for General, and a
modest amount for Amateur Extra. I passed them all at one sitting, no
sweat.
A huge amount of the Novice exam is what I would consider "common
sense". There are only a few questions about theory (like Ohm's Law),
RF safety, and operating privileges. The General and Amateur Extra
exams have progressively more questions on theory (e.g., impedance and
Smith charts).
I've mostly only operated "phone" mode (voice) on 2m/1.25m/70cm. Years
ago I was interested in packet, but that seems to have almost dried up
and blown away. I'm interested in trying RTTY and PSK31 modes on HF,
but I don't have any HF gear yet.
Eric