Oulun yliopisto

VLF Measurement Campaign 2008

Last update: 2015-8-28, 11:28:55 UTC.

2008-02-19: Preparing the site
Snow depth in Sodankylä around is 60cm and snow cover is thicker in Pomokaira area. Road to Kannuslehto cleaned in co-operation with Metsähallitus. Pertsa and Raimo took snow mobile to prepare the tracks around the antenna locations. They also fished out old places of the antenna stands.

2008-02-21: NS-antenna up
Six brave men started from Tähtelä to Kannuslehto after morning coffee. Deep snow was waiting. First we build masts and installation of the NS-antenna's stands followed this. After the tasteful outdoor lunch (sausage prepared in fire and coffee) everything was ready to lift the antenna loop up for 10m height. Tilting and distance between masts caused small problems, but after small tuning of wire cables the NS-antenna was standing in middle of snowy view. Measurement caravan was also pulled to the station site.

2008-02-22: EW-antenna
Light snowing which started already on Thursday continued. Small changes in the field group. Also Jyrki left the municipality and joined to campaign team. He use to be the eye which control the mast tilting. Thanks to preparation made day before the Lift up of the EW-mast was done quickly and team could start weekend on time.

2008-02-25: Measurement starts
Thanks to heavy snowing on Friday-Saturday we had some problems to get agrigate to the site. The road was cleaned but not enough well. Finally the first bits of this campaign was recorded at 1544UT. Already the very first hour offered some strong whistlers and triggered emissions. Tauno and Jyrki stayed at the station.

2008-02-26: Weak whistlers
0400-0600UT lot of weak whistlers, but too weak to analyse. Narrow band emissions around 3 kHz lasting some tens of seconds. Rest of morning was empty. Checking of the antenna orientation was done from the directions of the VLF transmitters (05-06UT). Day time quiet. Tero visited with Eva and Peter. Tauno explained the recording system and analysis to our LAPBIAT guests and showed some observed events. Unfortunately the sky was empty: just lightning strikes, some weak narrow band emissions and Russian ELF transmitter signals.
1600-1900UT some power line triggered emissions.
2000UT Hiss event and aurora arc in north, after 2140UT really good hiss event

2008-02-27: Coronal hole impact
SGO has now two UltraMASK Aarddvark stations in test operation. Receivers are in Tähtelä and Pittiövaara. Thomas and Tero spent afternoon in Pittiövaara studying the wide band noise source what we saw in UltraMSK and WWLLN spectrum. The source seems to be UPS which radiates electromagnetic noise. The faulty UPS was removed from the station.
Duties of municipality took Jyrki to Sodankylä and Tero arrived just on the moment when northern lights activated before 1900UT. Nice emissions which rose up to 4kHz. Whistler activity rose also. 22UT we were back in silence.2340UT some whistlers with hops. Temperature outside the caravan is -16°C.

2008-02-28: Morning chorus and huge aurora display
After active evening we have had nice morning chorus. Many types of emissions.
After 0830UT no events, but after 0900UT low band activates: lot of rising tones with hooks. Strong emission up to 2kHz.
Around 1130UT this unstructured strong emission fade out and came back later.
1430UT emission band disappeared, very quiet.
Jyrki replaced Tero at the station. Around 1700UT first break-up. Really bright auroras above but no hiss observed.
1727UT auroral hiss can be regonised and comes soon stronger. Also power line hum rises.
1734UT hiss event ended. Auroral activity continues.
2126UT Emissions.
2325UT Emissions, huge power line hum.

2008-02-29: Cold night...
Last night was really cold, -30 °C; was reached in Sodankylä area. 0450UT Morning chorus with emissions. We have one hour break in data because we lost power from the batteries of preamps. Change of batteries caused some contact problems. They were fixed at 0717UT. Cables does not like this cold. Tero arrived before 0900UT to take care about the station. Tauno and Jyrki left to SodankylÃä. EU Commissioner for Regional Policy will visit at the observatory today. Some short hiss bursts between 4 and 8 kHz observed aroun 1035UT.
1700UT geomagnetic activity continues: last hour full scale 500nT!
Some auroral hiss events.
2240UT Powerline syncronized emissions.
2330UT Some aurora activity with hiss.

2008-03-01: One was missing, but not anymore
0030UT pulsating auroras
0100UT Strong emissions
0730UT Morning chorus fades out
0900UT Discrete emissions occurs
The night was cold again but now temperature is rising quite fast. Tero left the station and Esa replaced him later.
1400UT Low band emissions
1730UT Seems that we have first MLR event of the campaign...
1910UT Really strong hiss event
1930UT some whistlers
2020UT VLF emissions are gone, clear sky, diffuse aurora in north

2008-03-02: Solar wind slow down
0450UT Morning chorus starts slowly
0630UT Still chorus comes stronger
0815UT Time to time chorus occurs on two bands
More guests arrive to Tähtelä including Russian Team. M. Rycroft visited at the station with Jyrki. Eva and Franta got some runs on the pistes of Luosto with Tero.
1850UT Hiss events. Tero and Fredrik took response about the measurement.
2100UT Looks like we might have second MLR event
2158UT First whistler of the evening and it is strong one.

2008-03-03: Miniworkshop starts
Group of our international colleagues visited at the station. Tero continued running the measurement. Morning chorus was observed again. Lot of emission around 14UT, which seems to be triggered by powerlines. Evening sector was quiet. Timo arrived to the station. At least one hissler was seen. Colleagues started to study the data measured during the campaign.

2008-03-04: End of the campaign
Just after midnight you could close yuor eyes and think that you are in middle of the jungle instead of Lapland taiga forrest. Night was mostly silent. Some strong lightnings. Low band activated and we had nice hiss event going on when Graig and David came to visit the station. After their visit it was time to stop the measurement at 0935UT. During the last hour Ãof the campaign we got first Pc1 events. Antenna's were left to the station site to wait, if we get interesting activity around equinox.

Last modified: 28 August 2015, 11:28:55.