Network Bandwidth Problems

Iam a solider with the 101’st deployed to Iraq and we just bought a satellite internet system. It came with a linkstar modem and a D-link Dss-24
switch. The problem Iam having is that the ablity to surf the web and downlad files swings wildly from 5kb a sec all the way up to 100kb a sec. When I run just one computer on the satellite Bandwidth is not a problem. How can I better manage the bandwidth when all 24 users are on.