I only use the antenna when travelling and have never measured it because it is always in different places anyway. When aligning the antenna, I always look at the db value of the signal. Below -80dB is then ok. If I'm already at -50bB to -70dB without an antenna, I don't use it at all because it's enough for my purposes and I only use an upload. The antenna can't manage more than -5 bB. It doesn't really help in an area with very poor reception.

No, I would not assume that. This product is more for support in mobile applications. For example, if you have a caravan, to transmit the signal from the outside to the inside of the caravan without any loss through the panelling. To achieve an improvement in a fixed location such as a flat or house, it would be much better to invest in a high-quality outdoor antenna that can then be outside in all weathers. However, the price segment for such an aerial is of course completely different. An additional zero would have to be added to the sales price.