How does it work?
(To stop the animation press your browser's "Stop" button, to restart press "Refresh").
For simplicity I have used only 3 sections of conduit in the illustration. The same principle applies to an 8 section pole. The only difference being the number of sections between the bottom section, which is held rigid and plumb, and the top section which has no pulley.
The winch is attached to the first or bottom section. As the cable is wound onto the winch, it lifts the second section from the bottom. Here's the trick...look closely at the second section's cable... one end attaches to the first section's pulley bracket and the other attaches to the bottom of the third section of conduit. As the second section is raised, so to is the third section and so on. As the cable is winched all sections, above the first section, extends identically.
BOTTOM LINE: To fully extend a 7 section pole to 50 feet requires that only 6 feet of cable has to be winched.