New multifrequency measurements with a HF radar in the equatorial electrojet have extended the range of wavelengths investigated during high drift velocity conditions to 50 m. It is shown that the socalled type 1 spectra can be detected at all wavelengths. Their phase velocity has a value given by the threshold for instability in the full dispersion equation and is constant with elevation angle and time when corrected for neutral wind effect. Spectral width increases with wave number, following a law Kn, n~0.7, but is constant with elevation angle. Ratio of spectral width to mean Doppler shift is of the order of unity at the lowest wave number and decrease as K-n, n~0.6. These results are compared to the existing numerical simulations and theoretical works.