HFU HF Underground
Technical Topics => Propagation => Topic started by: Skipmuck on December 14, 2021, 0145 UTC
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Just when you think you have a clue, things get more complicated.....
https://phys.org/news/2021-12-visualizing-propagation-path-electromagnetic-space.html
https://phys.org/news/2019-02-visualization-regions-electromagnetic-wave-plasma-interactions.html
https://phys.org/news/2018-02-scientists-electron-dynamics-northern.html
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Haven't read all of it yet but does it talk about the "magic cloud"? :)
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Hey All,
FASCINATING INFO !!!
I read along time ago( a bit fuzzy now) about ULF /whistler/ sferics being "conducted" down "tubes" in the magnetosphere and actually getting a measure of natural AMPLIFICATION from incoming solar radiation ,so far , the only known example of NATURAL radio amplification (??).
I also just read /printed a Hardcore Dx Medium Wave Propagation article by KN4LF, good stuff there.
de N1NQC
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My guy at haarp did studies back in the day that showed the idunnosphere reradiates sigs, not refracts them.There's llke 300k volts and zillions of amps up there just waiting for you to figure out how to make it into a triode.
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My guy at haarp did studies back in the day that showed the idunnosphere reradiates sigs, not refracts them.There's llke 300k volts and zillions of amps up there just waiting for you to figure out how to make it into a triode.
You Are Definitely fanning the flames of my Paranoyia to expedite my...
"Headin' off the Grid... >:(
Headin' off the Grid... >:(
Me shall be rejoycing.. ;D
Livin' OFF The GRID!!!"8)
( & believe me when I say "i am so serial you guys...")
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So much par up there it melted the shuttles kite string that one time.
https://rationalwiki.org/wiki/STS-75_incident
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Hey All,
FASCINATING INFO !!!
I read along time ago( a bit fuzzy now) about ULF /whistler/ sferics being "conducted" down "tubes" in the magnetosphere and actually getting a measure of natural AMPLIFICATION from incoming solar radiation ,so far , the only known example of NATURAL radio amplification (??).
I also just read /printed a Hardcore Dx Medium Wave Propagation article by KN4LF, good stuff there.
de N1NQC
Yup - the whistlers are essentially guided along one of the Earth's magnetic field lines, and can bounce back and forth between the hemispheres. It is possible to estimate the integrated electron density along the propagation path by looking at the shape of the whistler in a frequency-time spectrogram of ground-based measurements of these waves. Some researchers at Stanford mapped out the plasmasphere using these kinds of measurements before their work was corroborated by later spaceborne measurements (I want to say back in the 1950s or 1960s, and cannot recall the researchers name!).
There are actually a bunch of different instabilities in plasmas that cause waves to grow. Most of the naturally produced plasma waves in the ionosphere and magnetosphere start out as thermal noise that is amplified by these instabilities (whistlers generated by lightning are a notable exception). Some of these plasma waves are electromagnetic, while some are so-called 'electrostatic' waves that have a negligible magnetic component. A couple of decades ago I was in graduate school studying these kinds of waves using instrumentation on spacecraft. I've been fascinated by the ionosphere and magnetosphere for a long time, so it is kind of weird that I am just now getting interested in shortwave!
jason
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Hey All,
FASCINATING INFO !!!
I read along time ago( a bit fuzzy now) about ULF /whistler/ sferics being "conducted" down "tubes" in the magnetosphere and actually getting a measure of natural AMPLIFICATION from incoming solar radiation ,so far , the only known example of NATURAL radio amplification (??).
I also just read /printed a Hardcore Dx Medium Wave Propagation article by KN4LF, good stuff there.
de N1NQC
Yup - the whistlers are essentially guided along one of the Earth's magnetic field lines, and can bounce back and forth between the hemispheres. It is possible to estimate the integrated electron density along the propagation path by looking at the shape of the whistler in a frequency-time spectrogram of ground-based measurements of these waves. Some researchers at Stanford mapped out the plasmasphere using these kinds of measurements before their work was corroborated by later spaceborne measurements (I want to say back in the 1950s or 1960s, and cannot recall the researchers name!).
There are actually a bunch of different instabilities in plasmas that cause waves to grow. Most of the naturally produced plasma waves in the ionosphere and magnetosphere start out as thermal noise that is amplified by these instabilities (whistlers generated by lightning are a notable exception). Some of these plasma waves are electromagnetic, while some are so-called 'electrostatic' waves that have a negligible magnetic component. A couple of decades ago I was in graduate school studying these kinds of waves using instrumentation on spacecraft. I've been fascinated by the ionosphere and magnetosphere for a long time,
so it is kind of weird that I am just now getting interested in shortwave!
jason
Don't Forget To Bring Your Aluminum Hat! ::)
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Aluminum lets through too much of the bad energy used to read my thoughts.
I've gone over to a pure copper hard hat now :) !
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You need ferrous materials to block rf best, a viking helmet would be a good start.