Radio Observation
of Atmospheric Phenomena

Spectrogram of a radio wave reflection off a ionised meteor trail lasting about 60 s:

Radio monitoring basically means the recording of received RF-power. Irrespective of the technical implementation, at least some fundamental decisions must be made:

Passive monitoring of an existing RF-source

Radio monitoring in its simplest way engages a RF-sensor (=radio) and a recording unit. Receiving frequency, bandwidth of the sensing unit, signal-integration time, trigger threshold, recording-interval, date and total monitoring period have to be chosen appropriate to the objective. If more than one radio frequency should be monitored, the RF-sensor must allow for different frequencies controlled by an automatic system. In case of individual observation frequencies, a time/frequency schedule has to be set up for the control device. Otherwise, for a frequency-sweep the span and increment must be defined together with a schedule of the repetitons .

Active monitoring by generating a RF-signal and evaluate reported receptions from third persons

In this case the RF-source can be controlled by frequency, transmitting interval, transmitted power, modulation, signal protocol (digital mode), date and period. It requires to be a licensed radio amateur to work a broad range of radio frequencies. The actual monitoring is outsourced to third persons who feed their automatically generated reception reports to internet accessible databases.

Practical Implementation 

I utilised radio waves in the frequency range 10 kHz-200 MHz for the study of atmospheric phenomena. My studies focuse on (1) ionospheric topics and (2) meteor related topics. Here I present the outcome of my radio projects:

Radio monitoring of Ionosphere

I was looking for a way to visualize the influence of coronal mass ejections on the ionosphere in detail with the help of amateur radio equipment. It was done by transmitting WSPR-beacon signals and analysing the received reports. Thereby, a density plot of the reports per distance and time proved to be a good indicator of ionospheric disturbances. Read more.

Furthermore, a one-year study on shortwave propagation was conducted based on transmitted WSPR-beacons. After processing the 250000 WSPR reports, it was instructive to observe the textbook changes in propagation at the various frequencies specifically for my location over the course of the year. Read more.

Also I took the chance of the solar eclipse occurring 2015 in Europe to observe their effect on the ionosphere by measuring the propagation of low frequency radio waves. Different transmitters at different wavelengths in the vlf- and lf-range were involved. Their signals were recorded quasi-simultaneously for several days to see, how they deviate during the eclipse. Read more.

Radio observations with an AR5000 receiver

With the advent of SDRs, this radio project, based on the AOR AR5000 communications receiver, is of more historical interest. It was intended for monitoring ionospheric conditions. For this purpose, the AR5000 must be controlled by a computer via the RS232 interface. The required software was developed by me and can be downloaded free of charge (for Windows up to version 7). The software not only controls all settings of the receiver, but also records time- and frequency-controlled incoming RF signals, essentially the level of the automatic gain control (agc). I did some sample measurements to get an idea of the possibilities of this system. Read more.

Radio Meteor and Head Echo Analysis

My most extensive project is dedicated to the radio observation of meteors. After first steps in this topic soon my interest arised in the study of meteor head echoes. Thereby, the french GRAVES-Radar was used as a very powerful transmitter for meteor head echo reception. As a necessary prerequisite I developed a fast recording software with numerical output together with a second program to processes the gained data. Both scripts can be downloaded for free. The radio detectability of head echoes as well as the visualisation of meteor showers and major sporadic meteor origins based on meteor head echoes were covered in depth in several studies. Read more.

Sporadic E layer Forming

I investigated the occurence of sporadic E layers, which among other factors, is also dependent on the presence of long-lived metal ions of meteoric origin. This was done by analysing reception reports from all over Europe, generated by JS8 heartbeats I periodically sent out in the 11 m band. The solar and lunar tides in Es-forming could be well characterised. Read more.

Furthermore, I tried to reveal the influence of the amount of meteoric influx on the seasonal variability of sporadic E occurence. For this purpose, I used a whole year's worth of Es data from several European ionosondes together with the daily Central European meteor counts. Read more.