How does NASA communicate with spacecraft?

Why is a small communication bandwidth good?

In order to have many missions going at once (which is NASA's goal in the next millennium) each spacecraft must be less dependent on help from ground control. The more autonomous a spacecraft is, the less time ground crews spend maintaining it. This means NASA can run more missions without increasing the current number of ground controllers and amount of DSN bandwidth available.

The smaller the bandwidth sent out from a single craft, the less "space" it takes up in the field of available transmissions. This means more transmissions can be received and processed by DSN.

How is data put on radio waves (What is modulation)?
How much time on the DSN will DS1 get?
What is DSN?
What are radio waves?
What is the New Millennium Program?

How is extra data sent in the radio signal?
What problems are there besides noise?

How is data processing managed?
How do you make a radio wave?
What radio frequency does DS1 use for communications?