Sodankylä Geophysical Observatory
Ionosonde Instrument Description
Modified IS-14 sounder
Alpha Wolf (in operation since 16. Nov 2005)
- Modified IS-14 sounder (in operation since 1. Feb. 1977)
- Normal vertical sounding program:
- Half-hourly, centered at 2 MHz passage.
- RWD program:
- usually 6 ionograms per hour (several other programs are possible)
- Time used in scaled data:
- EET (30 deg E, UT + 2 h).
- Frequency range:
- 1 - 16 MHz
- Sweep time:
- 160 seconds
- Peak power:
- 2 kW nominal (actually much less is used)
- Pulse repetition rate:
- 50 Hz
- Pulse lenght:
- 50 microseconds
- Echo processing:
- Usually the quadrature components of 10 or 20 height sweeps are phase
coherently integrated in 1024 channels.
- Ionograms are currently recorded on 35 mm film. Echo is displayed from
the maximum of echo to the height where noise level, reference level or
minimum in echo pattern is reached. Height markers are at every 20 km.
Frequency scale is logarithmic and frequency remarkers at every 1 MHz.
- Gain control:
- Automatic. Dynamic range of displayed echoes is 20 dB.
- Rhombics in 64 m mast.