Hello Jacques

I Can not buil it myself since i know nothing about electronics.

Actual you do not know anything about electronics to build a loop
antenna, just make a wooden frame and wind some copper wire
on it, solder a variable capacitor to the wire and you are well of.

I havre no choice but to buy such an antenna in Us or Europe
What is the best product available in the Market ?
I've heard about Terk or Palomar .

If you will buy some thing, then take a close look here

http://www.wellbrook.uk.com/products.html#LA5030

I think the LA5030 is a good choise, but you will have to pay.

Regards Max