Radio Observation
of Atmospheric Phenomena

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

Spectrogram of a radio reflection off a ionized meteor trail

Radio monitoring means the recording of received RF-power. Independent from any technical realisation at least some basic decisions must be taken:

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. It must be operated by a control device. In case of distinct observation frequencies a time/frequency schedule has to be set up for the control device. Otherwise for a frequency-sweep the span and increment together with a schedule of timing the repetitons must be defined.

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.

Realisation

I utilised radio waves in the frequency range 10 kHz-200 MHz for the study of atmospheric phenomena. Here I present the outcome of my radio projects:

Radio monitoring via an AR5000 Receiver

Graph of ionospheric radio wave reflection during 24 h

This radio project was based on the AOR AR5000 communications receiver. It aimed at a monitoring of ionospheric conditions and sferics. For this purpose the AR5000 has to be controlled by a computer via the RS232 interface. I developed the necessary software which can be downloaded for free (for Windows up to version 7). The software not only controls all settings of the receiver but also records rf-signals basicly on the level of the automatic gain control (agc). The propagation of radio waves can be recorded at different frequencies and time schedules. I performed some exemplary exercises to get an idea of the possibilities of this system. Read more.

Radio Meteor and Head Echo Analysis

Density map of head echo slopes, identifying an draconids outburst

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 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 head echoes were covered in depth in several studies.  Read more.

Sporadic E layer Forming

Probabilty Map of sporadic E occurence in teh summer season

I studied the occurence of sporadic E layers by analysing automatically created reception reports from all over Europe. They were triggered by my own periodically transmitted JS8 heartbeats in the 11 m band (27 MHz, license free citizen band). This way, the nature of sporadic E could be examined and solar and lunar tides characterised. Additionally I tried to uncover the influence of meteoric influx on the seasonal variability of sporadic E occurence by analysing European ionosonde-data. Read more.

Radio monitoring of Ionosphere

Graph of vlf-transmitter locations

My radio monitoring projects include the observation of the effect a solar eclipse on the ionosphere by measuring the propagation of low frequency radio waves. The signals of different vlf- and lf-transmitters were recorded quasi-simultaneously. Read more.

Furthermore I performed a one year survey of radio propagation in the shortwave-radio amateur bands by transmitting WSPR-beacon signals and analyse the reception reports. The result is a site-specific schedule of general propagation conditions. Read more.