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Ldanielrosa

stable remote ground

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I'm working on a house that needs nearly everything brought up to code.  While the walls were open, I put in enough media drops to run an arcade (30 ethernet points, assuming I don't start using the 'phone lines too).  I gave it some thought, and decided not to include any heavy wire- so no speakers without a remote amplifier.

Anyway, the distance is moderate so the wire resistance may be as high as 2 ohms from the distribution point to the farthest box.  This could be highly undesirable if I wanted to power something through the signal wires, however...

The query is this:  Has anyone encountered anything whereby a moderate impedance, moderate negative voltage (-12 => Vsource => -48) goes through a switcher to provide a low voltage (=> -1V) for an alternate current path to keep ground stable?  Does this make sense to anyone else, or am I babbling out my navel?

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Dear Ldanielrosa Master (being a Priest),

you are NOT Babblin at all.

Earthing is an important but dry subject. please try to give little more details so that i could consolidate my reply- I had worked for 40 years in telecom and perhaps may be of some use to sort your problem

Regards
Sarma


First off, the priest thing is humor.  "I'm a ttibetan ppreist" is replacing the default line "I'm a llama".  In my country, most people with english as a primary language and nearly everybody with it as their only language pronounce "llama" as "lama".  The correct form is "yama", so when they are speaking of an animal they are saying "priest" instead of "camel".  So I put an extra letter in front of "Tibet" and "priest" to poke fun at them.

As for the subject of the query-  the wire I am using is 24AWG, which is about 0.084 ohms per meter.  It is the same for the telephone cable (cat3, 3 pair, bare ground with foil shield) as for the ethernet cable (cat5e, 4 pair, no shield).  I have found that some applications alloow for and require power transmitted over the unused pairs (+/-48V, 350mA), which does come within the specifications for a class 2 low voltage supply for residential housing.

Many of the gadgets I might dream of hanging from a media drop will use a single supply much less than 48V.  I also want to avoid the complications involved with ground currents interfering with communication.

The work-around that seems obvious is to use a negative supply to provide a current path to keep the ground (reference) unloaded.  I suppose this is an obscure niche- trying to provide a ground impedance at least an order of magnetude lower than the supply wires can give.

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Almost sorry to bump this to the top.  The only response I've had was by PM.  I'd really like to know if this is already done but with different names.  Seeing as I think orthogonally to most people, my searches don't yield as many results as they should.  Thanks for bearing with me.

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