Radio Observation
of Atmospheric Phenomena

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

Dear visitor,

this page is about different radio monitoring projects of mine. Hopefully it will be inspiring and informative. Basically, radio monitoring means the recording of received RF-power.

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, 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. A time/frequency schedule has to be set up or in case of 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

If a transmitter is used, the frequency, transmission interval, transmission power, modulation, if applicable signal protocol (digital mode), date and time period can be controlled. 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 operate either a web-sdr or a digital mode capable receiver feeding automatically generated reception reports to internet accessible databases.

Practical Implementation

My radio projects used radio waves in the frequency range 10 kHz-200 MHz to investigate atmospheric phenomena. The studies focuse on A-ionospheric topics as well as B-meteor related topics:

A: Radio monitoring of Ionosphere

My interest in radio monitoring started with the purchase of an AOR AR5000 communication receiver. It met all the requirements, necessary for genuine monitoring. Nowadays, with the advent of SDRs, this radio project is of more historical interest. The AR5000 can be fully controlled via a 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). Some examples of my measurements with this monitoring system are presented. Read more.

I took the chance of the solar eclipse occurring in Europe 2015 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.

A year-long study of HF propagation was conducted based on transmitted WSPR beacons. After processing the 250,000 WSPR reports, it was insightful to observe the textbook changes in propagation at different frequencies specifically for my location throughout the year. Read more.

One of my key questions was what conclusions could be drawn about the state of the ionosphere using amateur equipment. How can the impact of a coronal mass ejection (CME) on Earth be measured and analysed? My solution was to transmit WSPR beacon signals in the 40 m band and analyse the reports received. A density diagram of the distances plotted against the time of the reports proved to be a good indicator of ionospheric disturbances. Read more.

The same method was used to study the significance of the individual reflective ionospheric layers for wave propagation in the 20 m band. Here, the sporadic E layer could be identified as the central ionospheric element for short-range propagation within the dead zone of the F2 layer, throughout the year, but especially in summer. Read more.

B1: 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.

B2: 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.