AbstractVery low level plasma density and temperature fluctuations can be responsible for anomalous transport in thermonuclear magnetic traps. Electron cyclotron emission (ECE) detection has proven to be a very effective diagnostic for monitoring plasma temperature fluctuations at the frequencies of interest. Diffraction unfortunately limits the space resolution of this diagnostic with potentially important consequences on estimates of turbulent transport. This issue will be investigated both theoretically and with regard to technical implications. Experimental results obtained on the TEXT-U tokamak will be used to illustrate the previous point. Recent results obtained on TEXT-U with ECE, and corroborated by other fluctuation diagnostics, on the anisotropy of the high frequency fluctuations will be presented.