Remote controlled Avatar question.

[Pa'li Makto]

I wonder if the link can be adapted for underwater.

[Banefull]

If the neural link theory is correct, that would depend upon whether all of the neurons of the trees and other plant life are connected to the underwater flora. Plant life in Pandora's ocean might have just as many connections as the surface. Its interesting to think about.

[Woodsprite]

I think the "how much link time" line was referring to training back on earth, as the actual avatars started growing "on the flight out."

[Boba Fett]

Quantum entanglement and the like don't allow you create communication channels in any form that people would expect, so if the Avatars are not using radio, they are not using anything known to be physically possible. The only way to get information from one point to another is to send some particles there, and photons are the ones that travel fastest. You want it to be fast, it wouldn't be nice if you try to punch some skyperson and your fist gets one second lag.

If it is something that's known to be possible, it's either:
1. Standard radio waves (or other EM radiation).
2. Transmission to the tress, and from the trees to the Avatar.
3. Something funky such as neutrino transmissions. Why would anyone try to do that, I don't know.

Also the link seems to have a great range because Jake travelled a lot with his Avatar when he was calling the other clans, and the position of Polyphemus changes quite a bit when he does (I believe that Polyphemus should stay at a fixed point in the sky for any place on Pandora, so I use it to measure distance ).

Though I'd say I'm pretty much fine if it never gets explained how the link works, that would leave more possibilities. Though it would be cool if it is something I can't think of.

Originally Posted by Banefull

Some basic communication theory 101: Let us imagine if it were a radio transmission. These days, most information is transmitted digitally (gray code binary in particular) because it subject to less interference; however, human brain works with analogue signals. Analogue signals potentially can have infinite resolution unlike signal digital signals but they have are very prone to disruptions from outside "noise."

All known forms of analogue communication have a limited finite resolution, which is (very weirdly) often less than the resolution of the related digital form of communication. I would reckon that you mean that all analogue links (including those in the nervous system) come with some sort of natural noise, and that noise is very hard to represent exactly if you have a conversion to digital and back. As our organs and/or brains expect that noise to be there and might rely on it in some way, a digital link in the way could spoil the remote control. However, a conversion to another form of analogue signal (some conversion is necessary) would spoil it just as bad. So analogue link or digital link, you'd be facing a similar problem to solve, although the solution would probably be quite different. I'd vote that it would be easier with the digital one, cause you can do tricks with math.

If the link machines transmitted in analogue, the range would be extremely short. If you move far away, you will find that your body will twitch and convulse because the transmission is being subjected to small variations in signal amplitude difference.

Well, a digital link means that the digital data is converted to analogue and then transmitted. How can a digital link have a bigger range then? The range depends on the frequency, medium (trees, ground), power, how does the introduction of noise affect the signal, etc.

A digital link allows you to use math tricks to stuff more data into less data, and then transmit it in larger "quantities" (more modulation for a single data bit) ensuring that the other side will receive it correctly, and at even bigger distances after noise was introduced. However, these tricks are known to work with films, there's no guarantee they'll work this well with brain commands, or that we won't discover better analogue tricks to achieve the same in 100-200 years. Don't underestimate old good analogue signals, please.

[Ashen Key]

*grins* I just put it down to whacky, cyberpunk/psionic-ness. Which is possibly cheating, but it's the only way I see it as working.

[Human No More]

I already said the neural network isn't a possibility, sine the creation of avatars predates it, avatars are usually not linked to the network at all, and the links are not either (including being used while flying from Trudy's Samson).
Technically, the nervous system is actually closer to digital (although truly neither), with synapses acting like complicated logic gates and neurotransmitter levels building from an insufficient level to one which causes the synapse to become active. Radio waves would need significant power (impossible for return signal), a large transmitter and receiver, and some method of conversion (a digital signal is still transmitted as an analogue wave with digital, it is run through a converter and then interpreted as a digital signal at the receiving end - if a signal could be from 0 to 100, with 0-49 being digital 0 and 50-100 being digital 1, then when transmitted via a medium such as radio, interference may cause a 0 to, for example, be read as 40, this is then reinterpreted as 0 at the Rx, but was still sent via analogue transmission (codes such as check bits or CRC are used to detect if one or more bits have been flipped). Technically, most transmission of digital data, even via (non-optical) cables is analogue).
A quantum-based approach eliminates interference, range and power problems, but also the problem of feedback form the avatar such as senses, and does not need to have a permanent connection to the neural network (which is clearly impossible), as well as having a lower latency.

[SnowRider]

My biggest problem with the idea of the Avatar link being radio waves or some other EM transmission is this:

Where's the "receiver" located in the Avatar?

I.e., if it is radio waves or some other EM transmission, then there would by necessity have to be some kind of antenna or something made of metal in the Avatar such that the signal could be received and then "decoded" by the Avatar's brain.

So what, they put a very, very thin wire coiled up in the Avatar's body somewhere?

I don't think so. If there was anything made of metal in the Avatar, that object would have been subject to all kinds of eddy currents, interference, etc. from the magnetic fields and/or would have been fried or otherwise destroyed by those same magnetic fields.

You can bet that whatever method used for the Avatar drivers to link up with their Avatars isn't radio or other EM transmission.

You can't have the Avatar suddenly fall over if the transmission starts getting interference, enters the radio shadow of a mountain, etc. because that would be very, very dangerous to both the Avatar and the driver.

Whatever it is, the link method is secure, instantaneous, and immune from any kind of interference from magnetic fields or anything else that might disrupt or otherwise weaken the signal.