The antenna less efficient than 008,198 Optex

I use for some years Optex an indoor antenna reference 008198. I capture all TNT channels, but 2 multiplex (lower power transmitters) sometimes cause noise in the image or sound breaks. Including passage of a scooter without anti parasite, lighting a lamp, fridge open, weather etc ... also. This is quite rare, but happens.

From there, I thought my antenna randomly bought in a hardware store, was to be average, and I decided to buy a more powerful. So I searched on Amazon inside antenna having the largest number of positive reviews. I came to that displayed Meliconi 49dB amplification instead of 15db announced my Optex antenna.

Here is a comparison of the received signals for each of the two antennas (survey conducted on the same day a few minutes of intervals):
Note: NS = Signal level - QS = Signal Quality - If two numbers separated by ~ this means that the signal is between these values ​​and therefore not stable.

Meliconi
Multiplex R1 - NS 96 - QS 100
Multiplex R2 - NS 91 - QS 31 ~ 43
Multiplex R3 - NS 97 - QS 100
Multiplex R4 - NS 92 - QS 100
Multiplex R5 - NS 96 - QS 100
Multiplex R6 - NS 97 - QS 100
Multiplex R7 - NS 97 - QS 100
Multiplex R8 - NS 95 - 30 ~ 100 QS

Optex
Multiplex R1 - NS 96 - QS 100
Multiplex R2 - NS 93 - QS 50 ~ 60
Multiplex R3 - NS 97 - QS 100
Multiplex R4 - NS 93 ~ 94 - QS 100
Multiplex R5 - NS 96 - QS 100
Multiplex R6 - NS 97 ~ 98 - QS 100
Multiplex R7 - NS 97 - QS 100
Multiplex R8 - NS 97 - 35 ~ 100 QS

One thing is certain, these results show that a greater amplification does not necessarily improve the results. Return of the Meliconi antenna Amazon. The latter brought me even more parasite, even in multiplex chains in which I do not usually have.