Technical Project Managers

Are project managers required to be technically competent? Since technical competence is not a 1 or 0 thing, there is a continuum of the scale from being absolutely ignorant at one end to a master at the other end. Then there are shades of know-it-all PMs, but let us not get into that for now. So, how technically competent does a project manager need to be in order to be effective in his work? Is it that just a broad understanding of the underlying technology is sufficient or he should be some kind of an expert?

Really interesting. I think that among many other factors, this also depends on the size of the project. When the project size increases, the project manager may not be able to focus on multiple technologies. He may not be an expert of all technologies. In those projects, it is not possible to have a PM who is an expert in all technologies involved. The project needs to have its technical leaders as part of the core project group also.