ETNA RADIO OBSERVATORY
Live data from NICOLOSI (CT), Etna Park, Sicily
Maintained by ERO team
thanks to Renato Romero (vlf.it) for the idea of layout
This monitoring station is placed in the Etna Park that extends from the summit of the volcano to the towns surrounding it. Beautiful not only for its eruptions and for its lava flows, but also for the unique environment surrounding it, rich in sounds, perfumes, and colors. An enchanting landscape protected by a park you cannot miss the opportunity to visit if you are in Sicily.
System 1: Inductor EC200 (Ero Coil 200 mm)
Made with 30 km of 0.22 mm enameled copper wire (about 20 kg) wound in two coils connected in series (and in phase), inside of which is an iron core, consisting of 75 kg of 6mmq rods, individually resined, of two different lengths, 2 meters for the outer core and 50 cm for the inner core (under the coils) , for a total weight of 97 kg! A low-noise preamplifier, made from an OP27G frontend, as a balanced differential amplifier, provides the necessary amplification to drive the line input of the sound card directly. The power supply comes from a stabilized 12V power supply.
ERO COIL EC200 Specifications.
Coil 1: Outer diameter 25cm, Inner diameter 15cm, Width 20cm, Spire No. 11000, Wire diameter 0.22, Loop length 65cm, Wire length 7150m, R=0.7Kohm, Impedance=11H, Total Kg 7, Tare 0.7Kg
Coil 2: Outer diameter 25cm, Inner diameter 15cm, Width 20cm, Spire No. 34960, Wire diameter 0.22, Coil length 65cm, Wire length 22724m, R=5.7 Kohm, Impedance=180H, Total Kg 12.7, Tare 0.7Kg
Coils 1+2: No load Series Impedance 192H, Series Resistance 6.47Kohm, Weight 20Kg
Core: 50cm Iron Kg 16.2, 200cm Iron Kg 58.8
Plastics and coatings Kg 2.4
Total Kg 97.4
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EC200 - credits: www.etna-ero.it
EC200 core - credits: www.etna-ero.it
ELF and ULF MAGNETIC FIELD
Here below the first LIVE spectrogram, uSchumann resonances are marked in right side of the picture. Bottom part zooms on the 0,1 to 4 Hz range.
FFT resolution 10,5 mHz, scroll time 40 seconds.pdated every hour. It shows the last 8 hours ELF and ULF activity, as received by our coil (magnetic field).
ERO an example of a spectrogram , source COIL 8 hrs (click to open live view) - credits: www.etna-ero.it
Following the same signal, in 1 hour strips. Picture updated every hour.
This is the frequency range of schumann resonances, and a zone of deep interest to us, for the study of possible interaction of magmatic flow with the terrestrial magnetic field. FFT resolution 168 mHz, scroll time 4.6 seconds.
ERO an example of a spectrogram , source COIL 1 hr (click to open live view) - credits: www.etna-ero.it
Last spectrogram coming from coil shows daily strips, useful to compare activity from day to day, and to find anomalies. Picture updated every hour.
Scroll time 109 seconds and FFT resolution 10,5 mHz.
ERO an example of a spectrogram , source COIL 24 hrs (click to open live view) - credits: www.etna-ero.it
System 2: ORTHOGONAL LOOP
IdealLoop H301 system: http://www.vlf.it/feletti2/idealloop.html . Compact loop to receive VLF from 8 Hz to 20 kHz, with two 50 x 50 cm squared orthogonal loops.
ERO orthogonal loop- credits: www.etna-ero.it
RDF low freqeuncy magnetic field. Color indicates signals incoming direction.
Scroll time 11188 mS , FFT resolution 84 mHz.
ERO an example of a spectrogram , source orthogonal loop 2 hrs (click to open live view) - credits: www.etna-ero.it
And by the same reception system, the hourly multi strips.
Scroll time 4600 mS , FFT resolution 168 mHz.
ERO an example of a spectrogram , source orthogonal loop multistrips (click to open live view) - credits: www.etna-ero.it
RDF VLF magnetic field.
Scroll time 11 sec FFT resolution 91 mHz. Signal pre-filtered with Paul Nicholson's filter to reduce the hum noise.
ERO an example of a spectrogram , source orthogonal loop 2 hrs VLF (click to open live view) - credits: www.etna-ero.it
System 3: GEOPHONE
The geophone used in geophysics is a sensor designed to detect ground motion or seismic waves. The sensing element is similar to a microphone. The frequencies it can detect depend on the center frequency on which the sensor is built, in our case 4.5 Hz. The sensor is placed in contact with the floor, and the analog output signal is amplified and frequency matched to be processed by a sound card on a PC from which a spectrogram is derived using SpectrumLab software,
ERO geophone- credits: www.etna-ero.it
low noise amplifier - credits: www.etna-ero.it
Geophone Multistrip hourly representation, useful for local seismic and vulcanic events correlation.
Scroll time 4.6 sec, updated every hour.
ERO an example of a spectrogram , source GEOPHONE multi strips (click to open live view) - credits: www.etna-ero.it