Is the Fallout series all set in the same timeframe?

I was recently playing Fallout 4, and then noticed that effectively, everything is still the same in all the games - same setting, same technology, same Brotherhood, same ol' Codsworth.

So are all the Fallout games set in the same time period (give or take a few decades)?

Based on the image found on the timeline wikia page, Fallout 3, 4, and New Vegas all took place within 10-20 years of each other. However, Fallout 2 took place 30-40 years before them, Fallout Tactics and Fallout: Brotherhood of Steel took place roughly 30 years before that, and lastly (firstly?), the original Fallout took place 40 years prior.

So, while no game takes place more than half a century from another, the full timeline of the games spans roughly 120 years. As for whether they all fall within the same timeframe, it really depends on why you mean by the same timeframe. Considering the amount of time between the Great War and the latest game in the timeline (Fallout 4), the games are pretty spread out. It's highly unlikely that any non-ghoul (and non-Cabot) humans have lived through the entirety of the Fallout series, but it's likely that characters could live long enough to make cameos in other games (in fact, some do).