Data via wire and/or RF?

I'm guessing that I could send/receive more data via twisted cable than I could by IR or RF?
I'm thinking of that missile they control with a wire as the missile goes
toward a laser dot on the target. Tremendous amount of data being sent and received via a simple two wire. Am I wrong?
Thanks!
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Wayne Lundberg wrote:

At least with off-the-shelf equipment, I would imagine this is true.
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"The Artist Formerly Known as Kap'n Salty"

I believe this is consistent with Shannon's information theory. Given stereotypical environments, it is intuitive that the communication channel of RF or IR is much more susceptible to noise than a solid conductive medium.
Cheers Padu
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Wayne Lundberg wrote:

I believe if you investigate you'll find that the intelligence is mostly in the sight, that detects the degree to which the missile has diverged from its course and issues appropriate steering commands.

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I
goes
and
in
Sure, but vision requires a huge amount of data transfer and still don't know for sure which method would allow the faster exchange of data from point a to point b in both visual and control situations. I see a thin wire come into my home going to a box under my TV carrying over 900 channels plus three computers in my home on high speed internet on that same little wire carrying music and video. Could that be done with RF?
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On Mon, 22 May 2006 22:11:32 +0000, Wayne Lundberg wrote:

Free space has infinite bandwidth. The more of it you use, the more you spend on terminal equipment, but there is no theoretical limit. The main advantage of a wired connection is freedom from interference, both the RF kind and government regulations on what you can radiate.
At least some wire-guided missiles have _no_ brains or sensors in the missile. The controller tracks the missile, computes the divergence between the projectile's position and the line to the target, and sends pulses down the wire to fire off-center rockets at the correct moment to push the spinning missile back toward the correct path. Smarter missiles, like submarine torpedoes, have bidirectional data links, but the actual volume of data is probably modest by World Wide Web standards.
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Wayne Lundberg wrote:

But any "vision" is on the sight, not the missile. The sight sees where the missile is, sees where the spot is, and steers the missile onto the spot.

What does that have to do with missile guidance?
The only data that has to go down the wire is "a little higher", "a little lower", "a little left", "a little right". Basically you could handle it with two bits, three if you want to include "don't do anything", or you can add more bits if you want more control authority. The Germans managed it successfully (as in operational deployment in sufficient numbers with sufficient success for the Allies to start working on countermeasures) using audio frequencies. This isn't magic--any kid with a radio controlled airplane has the necessary technology in his hand.
Regardless, the Nazis were making experimental television-guided bombs using 1943 technology, with signalling both ways being wireless--they also had wire-guided variants which they never needed.
In any case, a broadcast TV channel uses 6 MHz of bandwidth--that just isn't very much.
Hint--what goes down the wire is RF, same as what goes over the air. The main benefit of the wire is that you don't have to get anybody's permission to use the bandwidth.
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permission
This is what I was looking for. Thank you!
Just brainstorming here.... if I had a wire connected from transmitter to receiver undeployed antenna... it would do the same as a deployed antenna?
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Wayne Lundberg wrote:

Maybe. Depends on the details of the circuit design. You're almost certainly going to end up overdriving the receiver, possibly far enough to damage it--remember that it's designed for less signal strength than it's going to be getting down the cable. Then there's the matter of matching impedances. Then there are likely other factors that I haven't considered--I know enough electronics to be dangerous, but not enough to be good at it.
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The
to
antenna?
be
Thanks John, I think I have found the solution. There was an interesting article in the San Diego Union Trib about a startup company http://www.signonsandiego.com/uniontrib/20060602/news_1b2wideband.html with the apparent solution to ultra-high speed and bandwidth for short distance communications for all venues. Very interesting!
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Wayne Lundberg wrote:

Not to mention, wire-guided means a lot less susceptible to jamming than wireless. That can be an important factor in a weapon's design.
JM
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