While it is difficult. Though by no means impossible, for the home constructor to build a parabolic dish - particularly from wire mesh material – it may be far easier to obtain a surplus dish from military,commercial or personsl receive-only TV use that you can adapt to your needs. Such a dish, a surplus C band (2 to 4 GHz) receive-only TV antenna, is shown in Fig 17-8 Most dishes operate efficiently at any frequency where they are at least a few wavalengths across, with larger sizes providing more gain, generally proportional to the area intercepted. The upper frequency limit of dishes is the frequency where surface irregularities or dimensional tolerances become a measurable fraction of wavelength.