This is a typical "bus window" shot, hence the smudgy bits that were caused by rain on the window.  I'm not clear about the purpose of this particular light - it is a beacon, or a sector light located on the northern shore of the Tagus, a few miles og the east of Cascais.  The details give above are from National Geospatial-Intelligence Agency Publication 113 but little detail is to be found in any of the other common sources.  Alex Trabas has a photo on his site and, interestingly, has applied the name "Marconi" to this beacon although there is no evidence that it fulfills any electronic role.