I never knew nor thought about the following before:
>"the International Space station has a repeater for packet radio"
[...]
"with VHF the higher the better. It lasts at most a few miles before hills, buildings etc block the signal. But a repeater can rebroadcast your message if it hears it, thus extending the range.
Imagine a repeater on a mountain, it can receive and rebroadcast so much, and its height works to an advantage because your neighbour’s roof or some local hill won’t get in the way because youre aiming over it. Now go further and imagine a repeater so high up that it’s in space
, why then even the humble VHF can reach insane distances!"
Great article!
(Also -- and I am no Nikola Tesla expert here -- but it is possible that Nikola Tesla (and/or other early radio pioneers) used outer space itself as a repeater... how that would be possible I cannot speculate with the limited knowledge I have on hand, but there seem to be some hints or at least "breadcrumbs" in the early radio writings / early "radio lore" -- that such a thing might have been possible...)
Early long distance communication often depended upon wavelengths suitable for ionospheric propagation, signals have been bounced off the moon, and (if I recall correctly) the earliest experiments in communications involved large reflective balloons.
Even though none of those are repeaters, the idea of using space to communicate over the horizon was something considered early on.
Now that I think about it, I wonder if it would be possible to use a second radio signal as a repeater, that is, bounce/reflect a radio signal off of another radio signal in other words bounce a wave off of another wave (in space)...?
While in all likelihood such a thing is not possible (although, I'm the last guy on Earth who would say that!), it would be kind of cool to envision a kind of Sci-Fi future where such a thing could be possible...
Perhaps more research in this area is needed... remember that a long time ago it was believed that Electricity and Magnetism were not related in any way, and it (apparently!) took Hans Christian Oersted (via electrical wire near compass needle) in 1820 (or thereabouts!) to show the scientific community that they were in fact related!
In fact, I'd even go a step further... I wouldn't want to just bounce electromagnetic radiation off of other electromagnetic radiation (although, that would be interesting enough, to be sure!) -- I'd even go so far as to say I'd be extremely curious if electromagnetic radiation could speed up, slow down, redirect, cancel and/or possibly reverse the direction of other electromagnetic radiation...
See, if we could accomplish some or even all of that... then we'd be at or close to living in a Star Trek-like future universe!
What you're talking about, roughly, is called beamforming. Pretty much all modern high-speed radio communication works this way. Essentially, by transmitting your signals through multiple antenna, you can create interference patterns which can collimate and amplify the original signal and point it in one specific direction. This involves a lot of calculations that must happen extremely quickly, so it hasn't been possible until relatively recently.
As to modulating the speed and direction of a signal coming from an external transmitter this way, probably not. I'm not good with the math involved here, but I don't think there's any way to reflect radio like this. We can reflect radio with special materials and geometries, but not through wave interference. I'm not aware of any mechanism which can slow down the propagation velocity of a wave other than through interaction with a physical medium.
If you really wanted to, you could amplify an external signal by broadcasting an exactly equal signal, which sounds suspiciously like a simple repeater. Canceling a signal is more difficult, conceptually it's the same problem as noise canceling in your headphones: you have to produce a wave exactly opposite to the incoming signal. In practice this is difficult to do for anything other than continuous noise like engine sounds. It doesn't work well for rapidly changing signals like voices or digital radio signals.
Beamforming, to recap, uses multiple radio transmitters acting in a coordinated fashion, along with specific fast calculations -- to modify the conditions of the combined radio wave at a specfic point (or points) of space...
So agreed, we have beamforming.
Now with respect to the various arrays of antennas acting in a coordinated fashion, aka "phased arrays" / "phased array antennas" -- if I think about say, a Starlink Dish -- I think about a whole series of antenna circuits -- on a 2D flat plane:
See, these (basically 2D X x Y grid) designs for beamforming radio transmitters are great and all, but I'd be immensely curious if there weren't some interesting 3D antenna geometries that could be couldn't be coupled with beamforming technologies... for example, what happens if someone were to make a 3D phi-spiral phased array transmitting (or receiving?) antenna array?
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[ 3.2 ms ] story [ 35.5 ms ] threadI’m waiting for someone to make a 1Ghz / 64GB model.
I never knew nor thought about the following before:
>"the International Space station has a repeater for packet radio"
[...]
"with VHF the higher the better. It lasts at most a few miles before hills, buildings etc block the signal. But a repeater can rebroadcast your message if it hears it, thus extending the range.
Imagine a repeater on a mountain, it can receive and rebroadcast so much, and its height works to an advantage because your neighbour’s roof or some local hill won’t get in the way because youre aiming over it. Now go further and imagine a repeater so high up that it’s in space
, why then even the humble VHF can reach insane distances!"
Great article!
(Also -- and I am no Nikola Tesla expert here -- but it is possible that Nikola Tesla (and/or other early radio pioneers) used outer space itself as a repeater... how that would be possible I cannot speculate with the limited knowledge I have on hand, but there seem to be some hints or at least "breadcrumbs" in the early radio writings / early "radio lore" -- that such a thing might have been possible...)
Anyway, great article!
Even though none of those are repeaters, the idea of using space to communicate over the horizon was something considered early on.
While in all likelihood such a thing is not possible (although, I'm the last guy on Earth who would say that!), it would be kind of cool to envision a kind of Sci-Fi future where such a thing could be possible...
Perhaps more research in this area is needed... remember that a long time ago it was believed that Electricity and Magnetism were not related in any way, and it (apparently!) took Hans Christian Oersted (via electrical wire near compass needle) in 1820 (or thereabouts!) to show the scientific community that they were in fact related!
In fact, I'd even go a step further... I wouldn't want to just bounce electromagnetic radiation off of other electromagnetic radiation (although, that would be interesting enough, to be sure!) -- I'd even go so far as to say I'd be extremely curious if electromagnetic radiation could speed up, slow down, redirect, cancel and/or possibly reverse the direction of other electromagnetic radiation...
See, if we could accomplish some or even all of that... then we'd be at or close to living in a Star Trek-like future universe!
Which would be... cool!
Ah, the future possibilities! :-)
As to modulating the speed and direction of a signal coming from an external transmitter this way, probably not. I'm not good with the math involved here, but I don't think there's any way to reflect radio like this. We can reflect radio with special materials and geometries, but not through wave interference. I'm not aware of any mechanism which can slow down the propagation velocity of a wave other than through interaction with a physical medium.
If you really wanted to, you could amplify an external signal by broadcasting an exactly equal signal, which sounds suspiciously like a simple repeater. Canceling a signal is more difficult, conceptually it's the same problem as noise canceling in your headphones: you have to produce a wave exactly opposite to the incoming signal. In practice this is difficult to do for anything other than continuous noise like engine sounds. It doesn't work well for rapidly changing signals like voices or digital radio signals.
Beamforming, to recap, uses multiple radio transmitters acting in a coordinated fashion, along with specific fast calculations -- to modify the conditions of the combined radio wave at a specfic point (or points) of space...
So agreed, we have beamforming.
Now with respect to the various arrays of antennas acting in a coordinated fashion, aka "phased arrays" / "phased array antennas" -- if I think about say, a Starlink Dish -- I think about a whole series of antenna circuits -- on a 2D flat plane:
https://www.google.com/search?tbm=isch&q=starlink+dish+teard...
This seems very similar to The University Of Alaska's HAARP:
https://www.google.com/search?tbm=isch&q=haarp
https://en.wikipedia.org/wiki/High-frequency_Active_Auroral_...
https://haarp.gi.alaska.edu/
But... that's not my point!
See, these (basically 2D X x Y grid) designs for beamforming radio transmitters are great and all, but I'd be immensely curious if there weren't some interesting 3D antenna geometries that could be couldn't be coupled with beamforming technologies... for example, what happens if someone were to make a 3D phi-spiral phased array transmitting (or receiving?) antenna array?
Some 3D version of something like:
https://www.google.com/search?tbm=isch&q=phi+spiral
Or potentially like:
https://cosmometry.net/phi-double-spiral-field-patterning#:~...
Or perhaps like:
https://www.facebook.com/photo.php?fbid=230792927111973&id=1...
Or even something like:
https://www.youtube.com/playlist?list=PLTS3UsPvxuStfe0VI3M1S...
You know, get something like that working with some Tesla Coils (https://www.google.com/search?tbm=isch&q=tesla+coil
https://en.wikipedia.org/wiki/Tesla_coil) and see what happens!
In other words, perhaps there may be more possibilities to explore here...
But yes, agreed, we have beamforming!