Sodankylä AARDDVARK Receivers

The Sodankylä narrow-band VLF receivers are operated within the framework of the Antarctic-Arctic Radiation belt (Dynamic) Deposition - VLF Atmospheric Research Konsortia (AARDDVARK). The nearest neighbours of our receivers are the Ny Ålesund and the Cambridge UltraMSKs of British Antarctic Survey. Our long-lasting collaboration with Lancaster University, U.K., has recently been extended: we constructed one more receiver system, which is currently in test use at Lancaster. It's final location is likely to be Scarborough.

SGO OmniPAL

Since 2002, there's a narrow-band VLF receiver operated by SGO. The receiver was initially co-located with a VeloxNET synoptic VLF experiment at Perunkajärvi near Rovaniemi, Finland, but later it was moved to the main field station of SGO at Pittiövaara.

The receiver is an old "OmniPAL" (omnifarious phase and amplitude logger) system hacked to run on Linux (thanks to Janos Lichtenberger). It is capable of recording amplitude and phase of up to six VLF transmitters at a maximum sampling rate of 10 Hz. Since installed at Pittiövaara, the receiver has been operated at maximum sampling rate all the time, because the unix-type operating system allows for daily data retrieval and thus diskspace was not an issue anymore. Currently we are monitoring the VLF transmitters with callsigns NLK, NDK, NAA, NRK, GBP, and DHO (see figure for great-circle paths).

SGO UltraMSK Receivers

In 2007, SGO purchased two licences for the UltraMSK receiver software. Receiver aerials and the respective interface electronics were built at SGO's workshop. The new aerials are magnetic loops of 3 m × 3 m on wooden frames with 10 turns of coaxial cable each. One of the receivers is placed at SGO. The other receiver was first deployed at our measurement station of Pittiövaara for testing before it was moved to Kilpisjärvi, which is at the border to Norway, about 85 km from the EISCAT Ionospheric Heating facility.

The new receives are able to monitor an arbitrary amount of transmitters, limited by the processing capacity of the receiver computer. In our case we are monitoring 11 stations simultaneously at the moment. These are DHO, GBP, HWU, ICV, ITI, JXN, NAA, NDK, NLK, NPM, NRK.

Observer in Charge:

Dr Thomas Ulich
Sodankylä Geophysical Observatory
Tähteläntie 62
FI-99600 Sodankylä
Finland
Phone: +358 294 480842
e-mail