To further what W8RMH said, besides allowing for an antenna to be shortened and still achieve resonance, some loading coils provide different functions like acting as a choke or trap at a certain point of an antenna so part of the antenna will resonate at one frequency and the entire length will resonate at another freq.
In the case of VHF/UHF antennas a loading coil or coils placed along the length of the antenna can actually be phasing lines to break up 1/4 wave, 1/2 wave/ 5/8 wave, etc stacked elements and provide a 90 deg phase shift between resonant elements so they all work in phase to provide gain.
The antenna provided in the first link looks similar to an old Radio Shack scanner whip and the coil loaded the antenna to resonate on VHF lo band. You might measure the distance from that antennas connector to the base of the coil and if its in the 16 to 18in range the coil may also break up the whip so the lower section acts like a separate VHF hi band antenna. If this is true that lower section would also work (somewhat) as a 3/4 wave UHF antenna, so with the cleaver placement of a coil the antenna could possibly pass as a tri band antenna.
prcguy