Doppler measurements with a digital ionosonde: Technique and comparison of results with incoherent scatter data

A simple technique for measuring the amplitude and Doppler shift of vertically reflected HF echoes has been implemented for the Arecibo digital ionosonde. This technique can easily be adapted to other digital ionosondes controlled by small computers and/or microprocessors to provide the additional Doppler information. By using this technique, we have measured on‐line the echo amplitude and the apparent vertical velocity of the reflecting layers. Furthermore, we have compared these data with simultaneous incoherent scatter measurements of vertical ionization drifts. The ionosonde and incoherent scatter results almost always agrree during the nighttime but do not agree during the daytime. We discuss these results.