With the EISCAT radars on the Scandinavian mainland it has been observed, that events of high electron temperatures and upward ion flows in the upper F region are often well correlated. During such events one can also frequently witness the development of so-called naturally enhanced ionacoustic shoulders in the radar spectra. The origin of the possibly superthermal plasma fluctuations, which cause the unusual echoes, has not yet been clearly identified. It is shown in this work, that very similar events, namely enhanced radar power after a period of increasing electron heating in the F region, can also be seen with the new EISCAT Svalbard Radar (ESR) at 74° magnetic latitude on the dayside. IS radars actually sense plasma fluctuation at slightly different wavelengths by varying cyclically the transmitter frequency. At ESR, during the superthermal enhancements, the received power seems to change significantly over the applied frequencies. This new observation favours a recently suggested model where ion-acoustic fluctuation are caused by the parametric decay of beam induced Langmuir waves. Other models of ion-acoustic “turbulence” would predict a smooth, Kolmogoroff-type k-spectrum, but in the parametric decay model the power of waves produced by this mechanism would indeed depend strongly in their wavelength.