transmitting an elecrical signal through water

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transmitting an elecrical signal through water

Postby jayhawk1970 on November 14th, 2010, 10:57 pm 

tough day. i need to send an electrical signal (either 8mhz, 33mhz, or 64mhz) through a pipe aproximately 200' with the resounding signal strong enough to be picked up by a hand held reciever. however the pipe is full of water and i cannot pass a solid object through it... ie a coppoer wire. i have already tried adding salt to the water but while it did carry the signal it was too weak to be detected by the reciever. whatever i use it has to be non-toxic and water solubale. i have heard of several things but dont know enough to understand. ie.. highly charged smaller ions (like what?) Pottasium hydroxide? soapy water? my transmitter is probalbly fairly weak as it operates off of 8 d batteries. i can provide more info if needed.
jayhawk1970
 


Re: transmitting an elecrical signal through water

Postby CanadysPeak on November 15th, 2010, 7:58 am 

jayhawk1970 wrote:tough day. i need to send an electrical signal (either 8mhz, 33mhz, or 64mhz) through a pipe aproximately 200' with the resounding signal strong enough to be picked up by a hand held reciever. however the pipe is full of water and i cannot pass a solid object through it... ie a coppoer wire. i have already tried adding salt to the water but while it did carry the signal it was too weak to be detected by the reciever. whatever i use it has to be non-toxic and water solubale. i have heard of several things but dont know enough to understand. ie.. highly charged smaller ions (like what?) Pottasium hydroxide? soapy water? my transmitter is probalbly fairly weak as it operates off of 8 d batteries. i can provide more info if needed.


I assume you mean MHz and not mHz.

Is there information in the signal? Otherwise you could try 8 MHz and sound. Not much coherence, I'm afraid - the pipe takes care of that! Of course, there's always Morse Code.

Why not much lower frequencies? They should work fine.
CanadysPeak
 


Re: transmitting an elecrical signal through water

Postby jayhawk1970 on November 15th, 2010, 9:44 pm 

this is not so much an issue of what is being transmitted as it is about what it is being transmitted through. the salt in the water is not transmitting the charge well enough. i need a better solution to carry a charge. the signal in electomagnetic in nature. similar to a sonde. ps. i have limited resourses to work with.
jayhawk1970
 


Re: transmitting an elecrical signal through water

Postby CanadysPeak on November 15th, 2010, 10:25 pm 

jayhawk1970 wrote:this is not so much an issue of what is being transmitted as it is about what it is being transmitted through. the salt in the water is not transmitting the charge well enough. i need a better solution to carry a charge. the signal in electomagnetic in nature. similar to a sonde. ps. i have limited resourses to work with.

I'll try once more. You ignored my questions. Are you seeking to conduct a current or transmit an em wave? Do you mean MHz rather than the mhz you typed? If you reply, please use the shift key; it matters a great deal in electrical work.
CanadysPeak
 


Re: transmitting an elecrical signal through water

Postby jayhawk1970 on December 3rd, 2010, 11:55 pm 

let me be more specific for those of you with college degrees. by mhz i mean mega hertz. i dont care how it is typed. i will say it again, it is not so much what i am transmitting as it is what i am transmitting through. the signal comes out of a little box that i plug two wires into and then connect to either end of the pipe. the pipe is pvc, it will not carry an electrical charge, an em or even sound for that matter. i dont need any more smart remarks. if you cant help me tell me so i can go somewhere else.
jayhawk1970
 


Re: transmitting an elecrical signal through water

Postby neuro on December 5th, 2010, 10:10 am 

jayhawk1970 ,
just sit down and make some computations.
The conductivity of salted water depends on the concentration of electrolytes.
You can compute that and compute the longitudinal conductance of your pipe.
Then consider that you will have capacitive effects.
The two together (capacity/conductance) will give you an RC coupling which is going to damp any high frequency signal.
Look at how attenuated is a low-frequency signal (e.g. the output of a 6-V AC power supply) using a simple tester.
If it is significantly attenuated, consider that you will presumably have a further ten-fold attenuation for each decade in frequency (50 Hz to MHz means some 1/20,000).
Add to this the fact that you are transmitting a single signal, presumably referenced to ground, and you might not have good grounding at the two ends of the pipe, which will get your signal even worse.

When you have finished computing,
try and exercise in understanding that people here (often quite more competent than a college student) are not supposed to waste their time in trying to answer badly specified questions posed by histerical bypassers who do not have time to better specify their problem, and go and look elsewhere if you really think that somebody will be anxious to solve your problem.
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Re: transmitting an elecrical signal through water

Postby jonathanjswift on June 7th, 2019, 11:33 am 

Does anyone know why my previous post was removed?
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