Standard TV Amplifiers will not work because of the sensitivity of the voltage of the TV link.
The only ones that I have seen that do work are the SLX range - which you can get from maplin or other electrical stores. (i.e. SLX 4X)
If you go to maplin.co.uk, they have a bargain at 19-99 for the 4-way SLX Booster that is definately compatible.
Good Luck,
Aez