Detecting radio wave intensity at a point

[astrokreng]

Hi, i was interested in a detector that could measure the intensity of a radio wave of a particular frequency, at a point. Either by using a capacitor or a radio diode (or any other way). If such a devise exists please tell me where I can find one, if not any advise on how I might be able to construct one. Thanks for any help.

[Integral]

It is not clear to me that what you want can be done as a direct measurement.

Instruments which measure RF energy are called Bolometers (http://www.infodotinc.com/neets/book16/67a.htm). These measure the power in a broadband. If the Frequency you want is the dominant frequency they are fine, if not, then they do not help.

What you may need to do is capture the signal present on an antenna which is tuned to the frequency you want. Then use Fourier analysis to determine the relative strength of the signal you want.