Radioron you're very helpful! the information you give me are very precious thanks!!!
perhaps you don't know
that with a simple led and a rf diode you can make the most simple "rf detector!" (i just learned how to call it..
)
the problem is that such thing is not so sensitive...it is only helful to
detect electromagnetic fields from mobile phones!!! (i guess above 0,5-1W max power)
both the site i found and the one you gave me i think they are very interesting and i'm planning to build one of them... but do you think i can somehow convert the design in the link you gave me and build a simple rf detector that can detect the presence of an electromagnetic field and light a led without the drawback of the above circuit i described?