Here's my 6 penn'orth. Bear Cub, you said
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"for a given radius of orbit there is only one speed....so change the radius with a burn and change the speed to catch the satellite...no?"
For a given orbit, if you acellerate (in the direction of the orbit) you will automatically move outwards into a larger orbit. Paradoxically, if you are trying to catch up with another satellite at the same orbital radius, you need first to slow down! That then drops you into a lower orbit, allowing you to cut the corner and 'undertake' your target before speeding up again and climbing to meet it!
Ever heard of 'Shepherd Moons'? (I know its a CD by Enya, but the real 'shepherd moons' are two satellites of Saturn (I think it's Saturn) which share very close synchronous orbits; one slightly higher than the other. The inner one gradually gets ahead of the outer one then, years later, slowly catches it up from behind. At that point they swap orbits and speeds.
"Coming nurse..."