Radio Spectrum Monitoring

Frequently Asked Questions

What is the purpose of the monitoring system?

The system was built to support assessments, analysis and discussions on issues related to radio silence, radio usage and science at Ny-Ålesund with routine radio spectrum measurements and an easy to handle graphical user interface.

What is the location of the monitoring system, when was it started and what is monitored?

The system detects and displays the strength of radio signals over frequency and time. The hardware was installed at the GFZ satellite receiving station in July 2023. Automatic collection of spectrum data started mid of September, but with a limited frequency range. The full frequency range, as described below, is monitored since 11^th October 2023. This website is open to the public since 1^st October 2024.

Which areas and frequencies are sensed?

The monitoring system uses 3 antennas. An omni-directional broadband antenna is mounted at the GFZ satellite receiving station cabin and provides a general overview. It receives signals from all around at frequencies from 20 MHz to 3 GHz. The other two antennas are directional by design (more gain but limited viewing angle) and receive frequencies between 2.2 GHZ and 2.5 GHz. This frequency range covers the satellite downlink band (as used by GFZ, Andøya Space and NASA), the 2.4 GHz Wifi/WLAN/Bluetooth band (used e.g., by consumer electronics and drones) and the nominal frequency of microwave ovens (about 2.45 GHz). One of these directional 2.4 GHz antennas is installed in the eastward GFZ antenna radome and points to the village (distance about 1 km). The other directional 2.4 GHz antenna is installed in the westward GFZ antenna radome and points to the airport parking area (distance about 150 m).

What is the operation principle?

The 3 antennas share one receiver. A time sharing is realised by an automatic antenna switch which connects the receiver to an antenna for 20 seconds, before it is connected to the next antenna, and so on. This means that all minutes of a day are probed with the same receiver and all antennas, but in different time slots of 20 seconds each. Within a 20 seconds slot the receiver repeately scans the frequency range that corresponds to the currently connected antenna (more than 50 times for 80 MHz – 3 GHz and more than 300 times for 2.2 GHz – 2.5 GHz). The produced graphics show only the signal maxima in the scanned frequency range, but not their duration. This means that a short signal like a pulse might be displayed the same as a longer or permanent signal, provided that these signals have the same signal strength.

Is the system capable to detect even short term and very weak signals?

No. Short radio transmissions might not be detected, at least not at all times. But there is a high probability to detect short transmissions from time to time if they occur repeatedly. Very weak signals might not be detected at all.

What is the system resolution?

The displayed frequency resolution is 0.1 MHz per pixel for the 2.2 - 2.5 GHz plots and about 1 MHz per pixel for 20 MHz – 3 GHz. A higher resolution is available from the measurement's raw data, which is also freely available (see buttons at the bottom of this website). The time axis uses UTC-time and a resolution of 1 minute (with limitations due to the receiver sharing scheme as explained above). The signal strength is presented in 1 dB steps on different relative logarithmic scales (not calibrated). The scale ranges were adjusted according to the signals and noise levels that are usually met with the different antennas. This means that very strong signals might exceed the scale maxima.

What signals are typically displayed on the 20 MHz – 3 GHz plots?

It is recommended to use the NySMAC frequency list to identify possible signal sources (https://nyalesundresearch.no/wp-content/uploads/2024/04/frekvensoversikt-nya.pdf). Below 200 MHz there are entries, e.g., for the 2 local FM-broadcast programs (solid traces at about 91 and 95 MHz) and VHF-radios, such as for marine, aircraft or research stations operation tasks (dashes or dashed traces). Some traces at higher frequencies correspond to telemetry systems and other special instruments (e.g., DORIS system at about 401 MHz and 2036 MHz and a "wind instrument" at 869 MHz). Some displayed signals might be “ghost signals“ from electronic devices nearby the monitoring antennas, the monitoring system electronics or inhomogeneity of antenna gain. Such “ghost signals” can usually be assumed to be constant in time and weak, and thus to be displayed as solid traces in blue colours. An example are the thin blue lines on the 2.4 GHz plots which appear in intervals of 80 MHz, beginning at 2.2 GHz. However, there might be also real signals that just seem to be “ghost signals”.

What signals are typically displayed on the 2.2 - 2.5 GHz plots?

Satellite signals (2.2 - 2.3 GHz) are usually too weak to be detected by the monitoring system. Most signals are detected in the 2.4 GHz band and the marks at the top of the plots may help to identify Wifi/WLAN- and BT-signals. Blue marks refer to the center frequencies of Bluetooth channels (2 MHz spacing) and yellow marks refer to the center frequencies of Wifi/WLAN channels (5 MHz spacing). Data traffic may produce thin traces close to channel center frequencies (BT, narrow band) or on both sides of the center frequencies (Wifi, broadband).

Does the system read, record or decode any signal contents or identifiers, e.g., such as MAC addresses?

No. The system is not capable to read, record or decode any signal contents. It only detects the strength and frequency of signals.

How to navigate in and between the graphics?

You may use the arrow keys on your keyboard to move the grahics on your screen and to toggle between adjacent days (shift + left/right arrow key) or weeks (shift + up/down arrow key).

Can I download graphics or raw data from the radio spectrum monitoring system?

Yes, you are welcome to download and use data from the radio spectrum monitoring system. For access you may just click the corresponding buttons on this website. Please cite us as:

Falck, Carsten; Reißland, Sven (2024): Radio spectrum monitoring at Ny-Ålesund, Spitsbergen.
GFZ Data Services. https://doi.org/10.5880/GFZ.1.2.2024.003

Radio Spectrum Monitoring

Frequently Asked Questions

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