If you are familiar with radio propagation you’ll know that radio waves do not naturally bend around the earth. Like light and indeed all electromagnetic radiation if they are given a free space they will travel in a straight line.
At very high frequencies this means that in normal circumstances once a receiver moves over the horizon from a transmitter that’s it, you’re out of range and there can be no communication. But at lower frequencies this is not the case. As you move through the lower end of the VHF into the HF (Short Wave) portion of the spectrum and below, the radio signal routinely travels far further than the horizon, and at the lower HF frequencies it starts to reach other continents, even as far as the other side of the world.
Of course, we haven’t changed the Laws Of Physics. Mr. Scott’s famous maxim still stands. Radio waves at these frequencies are being reflected, from ionised portions of the atmosphere and from the ground, sometimes in multiple “hops”. The science of this mechanism has been the subject of over a hundred years of exploration and will no doubt be for hundreds more, for the atmosphere is an unreliable boiling soup of gasses rather than a predictable mirror for your radio waves.
Radio amateurs have turned pushing the atmosphere to its limits into a fine art, but what if you would prefer to be able to rely on it? The US military has an interest in reliable HF communications as well as in evening out the effects of solar wind on the ionisation of the atmosphere, and has announced a research program involving bombing the upper atmosphere with plasma launched from cubesats. Metal ions will be created from both chemical reactions and by small explosions, and their results on the atmosphere will be studied.
Of course, this isn’t the first time the upper atmosphere has been ionised in military experiments. Both the USA and the USSR exploded nuclear weapons at these altitudes before the cessation of atmospheric nuclear testing, and more recently have directed high power radio waves with the aim of ionising the upper atmosphere. You may have heard of the USA’s HAARP project in Alaska, but Russia’s Sura Ionospheric Heating Facility near Nizhniy Novgorod has been used for similar work. It remains to be seen whether these latest experiments will meet with success, but we’re sure they won’t be the last of their kind.
We’ve looked at radio propagation in the past with this handy primer, and we’ve also featured a military use of atmospheric reflection with over-the-horizon radar.
Fishbowl Starfish Prime upper atmosphere nuclear test image via Los Alamos National Laboratory. As an image created by an officer or employee of the United States government as part of their official duties this image is in the public domain.
“Mr. Scott’s famous maxim still stands”: Actually, in that episode, they DID change the laws of physics. Or at least, discovered some new physics.
Sounds like militarization of space “and also investigate the possibility of blocking communication from enemy satellites”
the wording of the outer space treaty doesnt prevent military use of space nor weapons in orbit, only weapons of mass destruction, i realize you didnt actually claim this was in violation of the outer space treaty and i agree it is militarization of space, but that is a process that has been ongoing since we sent the first things into orbit.
Human’s started out about a million year ago in Africa and everywhere they went they brought warfare with them, what makes you think space (irregardless of treaties) will be any different?
One would hope that given enough time we would eventually stop trying to kill each other. It is a bit of a cave man mindset. It is like trying to speed up the Kessler cascade to block all access to the near infinite resources of space, it is a stupid thing to be doing. Leading to the eventual M.A.D. of all humans.
And this is somehow unexpected?
Oh, man. I can’t wait to see what the tin foil hatters make of this. Their HAARP stories are hilariously entertaining, while simultaneously saddening.
On a serious note, I wonder if this will reveal any new information for the fields of meteorology or atmospheric science.
Minor pedantry: Explosions are still chemical reactions.
Minor pedantry: An explosion is nothing more than an increase in volume rapidly and a release of energy.
Chemical reactions are the most common type but far from the only type.
There are also Nuclear, Electromagnetic, and Vapor explosions as well.
touche
There was an ‘over the horizon’ RF communication system called “BARS” (snow leopard) of the USSR which extended through most countries in eastern Europe up to the eastern part of the GDR, with the notable exception of Romania: [https://de.wikipedia.org/wiki/Troposphären-Nachrichtensystem_„BARS“#/media/File:Bars_a.jpg Map]
The system used mobile transceivers, think medium sized trucks, with dish antennas for beams that scatter at the Troposphere to extend beyond line-of-sight. The system was designed in the 1980s to be used after a nuclear conflict in Europe. Fuel and water in the bunkers was designed to last for one month. (Think about it.)
Due to the unique historic developments in Germany around 1989, the three stations on Germany soil where abandoned in a (relative) hurry by the Russian army. The bunkers were later turned into an exhibition by enthusiasts, who acquired and restored the original hardware and even managed to have the electronics repaired. I followed a tour in the bunker in Wollenberg (Station 301) a few years ago, and it was an amazing experience to witness these Cold War artefacts. I was told that the people who were actually interested in repairing the electronics, that is classified top-notch Soviet military communications systems of the 1980s, where retired West-German SIGINT engineers whose lifetime career it had been to understand these systems. History makes fun of us all our efforts, I think.
If you happen to be in Germany, I can recommend a visit. (Disclaimer: I am no affiliated in any way with the tours, and I don’t know if tours are still offered. The website of Station 301 seems currently broken.)
There were a number of tropospheric scatter communication networks built in the West with a few still working. The counterpart to the Warsaw Pact system you describe was NATO’s ACE High which had 82 terrestrial stations, located in 9 different countries.
https://en.wikipedia.org/wiki/Tropospheric_scatter
https://en.wikipedia.org/wiki/ACE_High
Indeed. Thanks for the links!
Troposcatter works better if there is a lot of dirt in the air, i.e. after bombing the
skyearth. This is different from what the author describes and uses GHz carriers, making for small dish-type antennas with a narrow beam.The interesting thing about the tour was that you can see and touch the stuff and have some expert explanation. They had restored it to the point of operation readiness and applied for a permission to run a test transmission, which was declined of course. In spades.
Well ACE High was UHF system in the 800-900 MHz and used very large fixed antennas as did the White Alice Communications System. Of course amateur radio operators regularly work tropo down at 6 meters and sometimes as low as 10 meters.
This was covered 10 days ago on slashdot: https://news.slashdot.org/comments.pl?sid=9544087&cid=52731299
The discussion there is pretty good and adds lots of information.
One of the links from there that shows the stuff in space is just scary – http://stuffin.space/
not a hack
So detonating bombs in space to enhance or jam radio communications is an every day occurrence where you live, and not strange, unique or unusual in any way. In my mind a hack is an idea of using something to do something you would not expect it to do. I think this is a hack.
In my opinion, hacks should be doable by normal people. HaD often writes about things that the military(industrial complex) or Academia have done. Which is fine, as long as they keep it in range of people with a limited budget, if you can use something analogous in your own project, or if it’s achievable to a normal person in it’s lifetime. Such as an article recently covered elsewhere where a guy builds his own plane because he didn’t like morning traffic.
Although I agree with your description of a hack, using your argument, you could nominate many more things as a hack. Giving the Hubble telescope “glasses”. Adding explosives to the outside of a tank to reduce or prevent the impact of kinetic ammunition. How are they in any way useful to a normal person except for saying, gosh, I never thought about that?
HaD is just adding these articles because people like explosions, and so they get more clicks. It doesn’t teach them anything they can use in practice.
Blowin’ shit up is ALWAYS a hack!
+1
All radio waves at all frequencies are refracted just as light is. Ducting at VHF is a prime example. I once observed a crisp test pattern from North Carolina in Arkansas which lasted for several hours. This was with an antenna that would barely pick up the stations 75 miles away. And contacts have been made from the west coast to Hawaii at a wide range of frequencies well above HF. IIRC it’s been done at 10 GHz and higher.
The governing physics is the relationship between the wavelength of the radiation and the variation of the atmosphere. Radio waves only follow a straight line in a medium of constant velocity. Moisture has a major effect. It’s the limitation on GPS accuracy for single station position fixes.
An interesting citizen scientist project would be to put a large number of stationary GPS receivers on the internet and then use the data to solve for water vapor variations at very high resolution. This has been done at low resolution with a few thousand receivers for many years. Compressive sensing and several hundred thousand ~$30 receivers could improve local forecasting a great deal.
Is radio-wave propagation used for weather forecast? Having geodesic grid of automatic stations exchanging short messages on descending succession of TX powers (or using successive approximation to detect the lowest TX power able to convey message) on a chosen representative set of frequencies would characterize the air masses between the stations and help build synoptic charts in real time.
So what after effects (apart from the intended ones) would we see if this were put into place?
Would radio telescopes have a harder time detecting distant galaxies/stars/etc?
Would there be any forseeable climate effects?
What could go wrong? They are paranoid about CO2 and CFCs but will do this?
Early in the 1960s was a balloon called ECHO 1 that was not quite moon sized but was a balloon sphere with a metal surface that reflected radio waves. Why not that writ large?
Here goes HBO again.
“The US military has an interest in reliable HF communications as well as in evening out the effects of solar wind on the ionisation of the atmosphere, and has announced a research program involving bombing the upper atmosphere with plasma launched from cubesats. “ – Jenny List
“David Last, former president of the UK’s Royal Institute of Navigation, is sceptical about USAF’s ambitions to counteract the effects of solar wind. When solar storms disrupt GPS signals, the entire side of Earth facing the sun is affected, he says. Ironing out those disturbances would require an extremely large and speedy intervention. “You don’t calm a stormy sea by filling in the gaps,” says Last.” – Source New Scientist
Parsing through all of the rhetoric regarding this subject matter… The question must be asked: “Why are the Americans so motivated by this new innovation?” Will it actually enhance HF communications? Will radio astronomy be impacted? No. IMHO it is only a blowback from a very pesky technology that the USAF wants to take a crack at coming up with a really nifty solution. What is that? sUAS illegal intrusions into US military installations.
So you may ask: “Why mount a LOCALIZED cubesat explosion event near edge of space (or wherever) to address this problem?” Well maybe they really don’t have a clue what to do so they are grasping at anything that will help. Help how? Well autonomous sUAS uses GPS or inertial nav for guidance – no remote control signals involved. We’ve covered that here at HaD too.
A student at UoT in Texas proved that the General Atomics MQ-1 Predator could be GPS-spoofed and give someone the alleged ability to arrest control (somewhat). Well what if that was not enough for USAF? They are always looking for “force multipliers”. What if they wanted to find a clever way to totally block GPS signals locally over a target? In that way they would not be disturbing GPS services globally. I mean they were doing something similar pre-2006 with Selective Availability and P-Code Anti-Spoofing, but have since stopped that technological foolishness – by order of POTUS Clinton.
Yes they are trying to make clever gadgets to interdict sUAS by physical means. But if they could tactically scramble a jet to dump some exploding cubesats over a military installation in response to an active or impending sUAS attack, well that would be one method. Granted it’s in its infancy and all the bugs need to be worked out. But there is a US DoD SBIR out there (AF162-D001) if anybody wants to take a crack at it. Some people (mostly universities) here in USA have already started.
Seems a bit extreme to me. I think the physical methods are better. But you have to spot them first with that method. This exploding cubesat method could be a prophylactic measure to proactively do around sensitive sites. But that does not address the inertial nav part. You need something to disrupt gyros and/or accelerometers for that I think.
Wait, I need to adjust my “tin hat” – :-P
:-D
Actually this is the most plausible explanation for this program I have read to date.