Hello!
I am leaving to live in Antarctica soon. I was interested in taking a kit with me to measure any Antarctic sferics. Does anyone know if there is already any coverage out there? It seems not, from what I see. I don't expect there will be many lighting events (or perhaps any?) there but if there are, it would be very interesting to see their frequency and locations!
Pragmatically, I would also like to know if anyone has any experience operating these at low temperatures (down to -50 regularly)? Insulation might help, but only if the preamp power consumption isn't too low! I may also need to run a long (10+m) between the preamp and the main boad; is this possible?
Thanks for any thoughts!
Hi !
It's the same as a station in Namibia. I'm going twice a year to south africa, but there are no stations installed until yet. Correct me, if I'm wrong, but there must be at least 8 stations in a diameter of about 500km, weather the network will detect a stroke.
But it's interesting to test !
Thomas
I would have thought that a single station could still provide information on frequency (and indeed, existence
) of strikes, but not triangular a location! However - getting 8 stations in such a small area (by Antarctic standards..) may be impossible even with many, well-distributed contributors...
(2014-06-23, 16:37)alexandicity Wrote: [ -> ]I would have thought that a single station could still provide information on frequency (and indeed, existence ) of strikes, but not triangular a location! However - getting 8 stations in such a small area (by Antarctic standards..) may be impossible even with many, well-distributed contributors...
We use six in region 3, if memory serves.
Maybe with long range signals and sensitive antennas ?
Thomas
Hi!
Stations some thousands of kilometers away from other ones should be possible. Their gain has to be set high, which is only possible when electric interference are low. Some small power supply not far away or a solar inverter in the neighbor house can easily destroy the performance of a station. It's not easy to answer whether a station will work. You just have to test it.
The long-range detection also depends on atmospheric and geographic conditions (i.e. good propagation over wet surface, bad over dry surface).
Regards
Tobias
(2014-06-23, 16:09)alexandicity Wrote: [ -> ]I am leaving to live in Antarctica soon.
Pragmatically, I would also like to know if anyone has any experience operating these at low temperatures (down to -50 regularly)? Insulation might help, but only if the preamp power consumption isn't too low!
I built a laser interferometer for a client a 6 or 7 years ago that needed to operate at similar temperatures.
It was impractical to get all the parts with such extended temperature ranges so I ended up putting the equipment in a diecast metal inner box. Using some simple electronics and power resistors bolted to the metal box, it could maintain a temperature of around 0 deg C even in very hostile weather. The inner metal box was then mounted inside a well insulated outer case. It did not take very much power to keep it warm enough to be happy. I think it was under 10 watts in the end.
Just a thought.
For outside use I suggest E-Field Antenna (easy to isolate) and an extra resistor as heater (100 ohm direct on coax terminals, only 0,2W??? ) - maybe resistor heater via extra wires ?
- PVC tube inside plastic foam tube
H-Field (loop/ferrit) can be placed inside, or outside in a thermobox - 5 volt heating resistor
http://vlf.stanford.edu/research/whistle...antarctica
http://wwlln.net/
/richo
(2014-06-23, 21:36)RichoAnd Wrote: [ -> ]For outside use I suggest E-Field Antenna (easy to isolate) and an extra resistor as heater (100 ohm direct on coax terminals, only 0,2W??? ) - maybe resistor heater via extra wires ?
- PVC tube inside plastic foam tube
H-Field (loop/ferrit) can be placed inside, or outside in a thermobox - 5 volt heating resistor
http://vlf.stanford.edu/research/whistle...antarctica
http://wwlln.net/
/richo
As Richo suggests, you are going to need a heater. The parts are "industrial grade" good to -40C. I would be concerned about the electrolytic capacitors freezing at these temperatures. When I worked for an automotive supplier, we had a electrolytic capacitor that would freeze solid at -37C. This dramatically affects the capacitance value (82uF went to a few nF) and you will have all kinds of noise.
Make sure that whatever controls the heater is quiet! (both running and on/off events)
Greg
I would suspect a h-field would be best, as depending how your getting your power, a local generator might destroy a e-field sensitivity.
Impossible to tell because we don't know the sorroundings.
Generator have a huge magnetic field, but placed in a metalhouse (faraday) will short E-field.
Just wondering out loud here...
Does the fact that the South Pole is close to Antartica, have any impact on the magnetic fields produced by the lightning strokes? I.E., are the calculations still valid for stations located at either the North or South Poles? Aren't the Earth's magnetic fields concentrated at the poles and thus wouldn't that have an effect on lightning-induced magnetic fields?
Sorry, just questions, but no answers...
Any updates ?
2 stations now running in Southern Africa and detecting strokes 11,000km away. So it should be possible to run a station in the Antarctica too !
Where will this station be located ?
Thomas
If you put the station right at the pole, all directions will be North....
Seriously, industrial rated electronic components are rated to -40C. You may need to place the amplifiers and controller in heated cabinets. Of course, taking care that the heater controllers don't create noise. Sounds like a challenge.
Hammond makes some PTC cabinet heaters that might work. I have my RED system out in the garage and I use one in the cabinet there.
Hammond Heater Catalog
The parts that might cause the most problem will be the electrolytic capacitors. When the electrolyte freezes, the capacitance will be dramatically lower. I saw this effect in an automotive application, where the power supply got very noisy due to the capacitance change.
You might be able to substitute some parts for -55C "military grade" specification.
Greg H.