The more tight sharing of UHF spectrum between mobile and TV can lead to interference issues, mostly from mobile base stations and handsets – depending on the precise frequency arrangements, onto stationary TV. This specifically occurs with higher power signals, which tend to reduce the effectiveness of tuner selectivity in receivers. Theoretical studies were done proving this problem is difficult to manage while using the spectrum efficiently. Frequency selective filters on TV antenna inputs (suppressing the mobile signals) can reduce the problem. Currently there is a trial ongoing in the UK to get more feedback from real life situations: i.e. maybe things are not as bad as they seem and maybe there were a few issues that the specialists forgot about.