Marios Lazos schrieb:

Hi you all there!

I need to build an antenna preamplifier for the FM band.So after a short looking i found the follow Fets:BF198,BF199,BF173 to design

Those transistors aren't FETs, just silicon npn transistors for
RF applications. You can find the datasheets at

http://www.datasheetcatalog.com/

HTH

Reinhard