Despite the unfavorable opinions, trusting the brand I purchased this product with saying hopefully it would improve the external antenna signal before entering the DTT decoder: disaster! Not only it does not improve at all some signal of the setting but the DISTURBED completely. Indeed we lost the chains we had and did obviously not recovered those whose signal was poor. Everything becomes jerky and hatched, whatever the increase in dB chosen. Furthermore this adjustment and the increase is actually not 25dB as indicated on the packaging but 10 dB (?!?). In short: it is worse with them than without. Save 25 euros. You can trust the previous reviews!