The satellites have many different types of orbit.

Some satellites are 22,000 miles up in geosyncronous orbit, meaning that they orbit the earth at exactly the same rate the earth rotates. This way they seem to stay stationary in the sky. The many commercial satellites are like this so you can point a 10' or 18" dish at a fixed point in the sky to get commercial TV programs. But a geosyncronous satellite can only cover about 1/3 of the earth, and the coverage is from a long way away.

Other satellites are in orbits that are not syncronous with the rotation of the earth, meaning that over a period of time all of the earth will get a chance to get footprint coverage. An eliptical orbital path takes the satellite near the earth at times, and far from earth at other times. Most of the well know amateur satellites such as AO10, AO13, and AO40 are placed in eliptical orbits. When the satellite is low, say 300 miles high, the signal is strong, but the footprint (coverage) is small. Then the eliptical orbit swings the satellite as much as 24,000 miles from earth. Now the signal becomes weaker, but the footprint covers about 1/3 of the earth, great for working satellite DX. Over a period time, hams all over the earth get a chance at the satellite. Low power stations can use the satellite when it is low, and big stations can work satellite DX. Coverage can last up to 6 hours. If AO40 works when turned on in 9 months, it will be a very great satellite for SSTV.

A satellite orbit can be more circular, generally at a lower altitude of 300 to 1000 miles up. AO27, UO14, SO35, FO20 and FO29 have low orbits that will provide coverage over a 2000 to 3000 mile circle. AO27, UO14, and SO35 are single frequency FM voice repeater satellites that come in very strong with tons of QRM on the single frequency.

FO20 and FO29 are SSB and CW satellites orbitting about 700 miles up. The band of useable frequencies is 100 Khz wide and not used very much. These satellites make about 4-5 passes a day over any location.