Most Portuguese citizens are 65+. Since CRT's were built to last, they won't even bother exchanging them. So operators send signal in analog so that people don't need to buy a DVB-T TV or a DVB-T receiver and keep everything as it was. Real DVB-T (sent over-the-air) is in DVB-T MPEG4 and the service provider receivers either use DVB-S2, DVB-C or IPTV. Portugal as a policy that most countries don't have: Every TV receives at least some channels from the package without a service box in open signal, usually in Analog but Fibre operators are starting to send some in DVB-T too
No. This are not the same things, what you intend to do.
DVB-T
DVB-T is the digital terrestrial television and thus comparable to the old TV antennas on the roofs for analog television. The nice thing about the DVB-T antennas is, that they are very small in contrast to the old antennas and can be also used as an indoor antenna. Likewise, you can also use your old antenna for DVB-T.
DVB-S
DVB-S stands for digital satellite TV. Here, the TV is broadcasted through a satellite and then lands on the satellite dish on the roof and via a DVB-S receiver in the living room.
DVB-C
Digital cable TV is called DVB-C (C for cable). At cable TV, a cable connection of the house is required and you receive your television over the cable network.
As you see all is digital video broadcasting.
What you want, as far i know is the satandard of all TV SETS ( analogue tuner ) to be able to receive VHF and UHF, still used for some operators. This type of signal do you have all over your house, cross the coaxial cable, even if you have an installation like ITED2, ITED or RITA.
best regards
nunigaia