A survivalist by trade, Tycho is a veteran of the wastes. He carries a gas mask (just in case), wears hardened leather armor and carries a shotgun, a knife, spiked knuckles, and a canteen; all the usual survival gear. Most just see him as a random man in dusty leather armor, with a gas mask hanging around his neck, goggles to keep out sand and glare and a sand-colored trench coat usable for camouflage and to keep the sun off. The double-barreled shotgun slung on his arm further confirms the feel that he's just another mercenary.
However, in reality, Tycho comes from the Desert Rangers, a small, but formidable faction from the Mojave Wasteland and beyond, experts in survival and self-styled peacekeepers of the wastes. His background gives him immense knowledge about life in the desert. He took off to wandering the desert with traders and explorers for several years, returning from time to time with goods or maps. Tycho started with small trips and went further abroad as he became more experienced. He went as far as the Gulf of Mexico in Texas and then headed back west.
Eventually he wound up on the west coast as a long-range explorer for the Rangers, stopping in Junktown for some rest and relaxation, just as the Vault Dweller comes to the settlement to kickstart a small revolution.
To obtain Tycho, the Vault Dweller must head to Junktown and be at the Skum Pitt located in the far North Eastern part of the city at 5 o' clock. He will join indefinitely if having taken on Killian's quest to deal with Gizmo. If Killian is dead, Tycho becomes non-recruitable.
Due to sprite limitations, he can only use rifles, shotguns, small handguns and spears. He has 60 Hit Points. It is unwise to give him anything with a burst function; he wastes ammo and can accidentally cause friendly fire (to civilians, including companions) if they are near his target when he uses the burst function.
Tycho can also teach some survival skills, raising the Outdoorsman skill.
A military place like this must have a central command room somewhere. I bet we could get through those force-field generators with a little hot-wiring, or if we could find the force field control computer.
Tycho's grandfather was a Desert Ranger (the Desert Rangers are a reference to Wasteland, a game from 1988 which is considered to be Fallout's predecessor). Tycho also mentions the "fat freak" from Las Vegas, which is a reference to Fat Freddy from Wasteland.