In our work on the amplification of Bleustein‐Gulyaev waves in photoconducting CdS crystals, we have found that the gain as a function of electric field is quite symmetric about the synchronous value. We have therefore been able to achieve amplification with a segmented structure consisting of an interdigital electrode. The unequal spacing between fingers produces amplification in the region where the field is positive, which is in excess of the attenuation in the region where the field is negative. The spacings between adjacent electrodes are 500 and 250 &mgr;m, giving a periodicity of 850 &mgr;m; the length of the active region is 6 mm. The experimental electronic gains obtained were 19 dB at 43 MHz and 32 dB at 86 MHz with an applied voltage of 130 V; 4 dB net gain was obtained at 86 MHz. It has been observed that the electronic gain is sensitive to the photoexciting light wavelength. We give an interpretation of this phenomenon based on the relative penetration depth of the mechanical wave, of the photoexcited carriers, and of drifting electric field.