[amsat-bb] What preamp to use for SO-50 and Arrow II antenna?

Since a lot of people are talking about SO-50 right now, let me ask a question:

I did try to work SO-50 once when all I had ever worked before was SO-35, UO-14 and AO-27 and I was horrified by how hard it was to hear and track.

I found a thread on qrz.com where they said it's very helpful to use a preamp for SO-50 since it's so low power, even with the short runs of coax required for an Arrow II satellite antenna. I know almost nothing about preamps. What's the deal? Do they need power to work (active/passive?). What do you recommend?

John Brier, KG4AKV, Raleigh, NC, FM05