Steel wire carrying twelve volts ?

This is the best advice yet. The higher the voltage you run, the lower the current and lower the voltage drop. Can you find 220 to 48 volt transformers? Pay close attention to the use of transient protection. Even so, you will more than likely loose a few routers.

On Apr 26, 10:03=A0am, "Tom M" wrote: =2E..

If you can find the parts cheap, you could turn whatever is left of the 48VAC to 24VAC with a 2:1 transformer, a 120:240 one would be fine, rectify it and charge a used 12V car battery. If the charging current is too much you could limit it with a light bulb in series. They are pretty close to being constant current regulators.

I put that in just for fun to see if anyone might query it. Water wont flow up hill unless pushed. Tho as an afterethought, there might just be a miniscule slowing of the electrons uphill . Effect caused by gravity, if electrons hace some mass. Probably un measuable Thanks for responding Ted Dorset UK

the best advice you have so far is to use aprox 48VAC on one or two of the top most wires to send the power up the hill to the router, then convert back down to whatever you need for the router - the router itself probably has a switching power supply that can accept inputs from about 100 to

300VAC, so if you start out with 220 to 48 transformer at the bottom and put a matching transformer at the top, the result will be a lower voltage that is still within the tolerance of the router's power supply.

Be sure to protect against weather.

Note- if you get enough rain that the soil stays reasonably damp, you only need one wire, ground the other side

also remember that power = volts times amps, so if you increase from 12 to

48V, your current goes down by 1/4, as does the voltage drop across the length of wire. ** Posted from **

I figure 7.7 ohms for 1000 meters of 4 millimeter iron (steel) wire, so drop of about 3.9 volts at 0.5 amp. I'd find a source of 16 to 24 VDC for the drive end, put a 12-volt regulator (e.g. LM7812) on the load end. The regulator costs about a dollar. It'll need a bit of heatsink, perhaps a piece of ally 10 cm square or so. It can be bent as desired to fit in a space.

Since the load is probably not constant, you can't use the resistance of the wire in an equation. The resistance is constant, but at different loads, the voltage at the end will vary.

So, you MUST have a voltage regulator (type power supply) at the router end. The voltage on the wires must be enough to overcome the resistance at full load, but does not need to be precise, could be AC or DC, whatever fits the voltage regulator input.

Sorry, I can't suggest a pr>

You have to supply the intended load for there to be any voltage drop.

Jon

To get the distance at lower voltage drop, use 50 Hz or 60 Hz AC dropped down from mains power - I would start the experiment with a 24 VAC input using the top (#1) wire as a "guard wire" grounded lightning sink, with a ground lead going down the back side of the post to ground rods at all the high points along the route. If lightning is going to hit, you want to try and divert it from your power leads.

Make the #2 and #3 wires from the top your power leads, taken loose from the fenceposts and mounted on ceramic insulators, and see how the voltage is at the far end under load. The insulators will cost a bit, but increase efficiency a lot - especially with the existing wire stapled to wooden posts, when it rains the power will /all/ go away as it leaks between the wires at 200 high-resistance shorts. When you are only starting with 50 VA or less at the feed end it doesn't take much loss at each post to suck it all up.

Anything below 50V with a current limited source is considered Class

2 Wiring in the US, and IIRC the rest of the world is about the same. It will give the cows and sheep a tingle if they touch it, but that's about it - much lower voltage than a fence shocker generator, but you still want to use only enough voltage to get the job done.

At the feed end, my best guess for a starting point would be a 240V to 24V at 50VA transformer meant for running Air Conditioning controls, they are reasonably cheap. Fuses on both sides, and a healthy lightning arrestor tied to a good ground rod.

Telephone lightning arrestors should work perfectly for that voltage and be reasonably priced, they have about a 150V strike-over because ringing voltage is around 120V AC 20 Hz. And the newer three terminal gas-tube arrestor devices form a plasma and clamp both lines of the pair to ground at once, to avoid sneak current failures.

If your area gets nailed by lightning often, you could also put arrestors at all those mid-run ground rod locations. But due to added expense you might want to wait till the first time it all gets "blowed up good" and you realize it wasn't enough. Your call...

Wherever there is a gate, bury a length of PVC Plastic conduit with the long sweep ells between the fence posts and under the opening. Take the two power and one ground lead and convert to heavy gauge stranded copper wire for the short run, then back to fence wires. Might be a good location for a ground rod.

At the top of the hill you attach another healthy lightning arrestor across the two power leads connected to a ground rod, then rectify and regulate to the 12V DC the Ethernet repeater is going to want. And put a healthy crowbar zener on the 12V DC output, to try and save the repeater from a lightning strike or regulation failure.

If it all works as planned, go to a local print shop and have simple warning signs made up - Print them two-up on A4 Goldenrod or Red paper and cut in half (5" x 8") then heat laminated with a large border, and staple them to every fourth or fifth fence post through the laminated border. They will last several years if the paper remains sealed off.

"Warning - avoid contact with insulated fence wires. 24 VAC Class II Current Limited power for Wi-Fi Ethernet repeater system on top of hill for the (Name) residence. Safe for accidental contact. Please do not short or ground fence wires. Enquires contact Hori at (address/phone)."

Nothing fancy, but keeps the kiddies from playing with it, the local loons from inventing UFO conspiracy theories (Yeah, as if that would be enough to stop them...) ;-) and the local Law Enforcement/ Fire/ Wildlife authorities from freaking out about exposed wires.

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Ohh, this is different. Hopefully the router isn't too expensive, because any lightning anywhere nearby will be picked up by the long run of straight wire and deliver a massive ZAP to the router. You will need to clean and solder any splices/joints in the wire. I'd look carefully at rigging a low-voltage transformer at the source end to run something like

24 - 36 V AC on the wire, and then converting to DC with a transformer/rectifier at the router. This might give you a little isolation at the router end, too, which might keep lesser lightning events from frying it.

This can definitely be made to work, but due to the high resistance of the wire, it takes just a little more complexity to do it. The 24 or 36 V transformer at the source end (remember to fuse it to protect against something shorting the fence) should be easily found, might even be able to find a wall-wart with that kind of output. For the router end, you could use a transformer with a tapped secondary as an autotransformer (although that defeats the isolation mentioned earlier) to bring the 24-36 V from the fence down to the ~12 V needed for the router. Also, a transformer with both 12 and 24 or 36 V secondaries could be used, connect input to the higher secondary, output from the lower one. Leave the 230 V primary disconnected and taped off.

Jon

And, that's why he planned power plants even closer than the OP's need of 500 M transmission. With proper insulators and elevating the wire above people's reach, it would make the most sense to sent the 230 V to the remote location, but the wire is already where it is.

Jon

Do your calcs for voltage drop at .4 amp and see if you can just put higher voltage in to counteract the drop. I'd throw 24 at it and use a

7812 regulator to control the voltage at the router. Also be VERY carefull if you are in a thunderstorm area. Non twisted pair is a GREAT antenna. A friend was loosing his fence charger every time lightning struck within 2 miles untill we installed a surge arrester (air core choke and spark-gap) His 3 miles of fence was picking up several 10s of thousands of volts (at low current) blowing the outputs on the fence charger. With the choke installed it's been trouble free for over 5 years. ** Posted from **

In rural areas it is quite common to have several thousand volts on fences - pulsed of course, to teach the animals that the fences mean business. They are often powerfull enough to keep the grass and scrub "trimmed back" from the fence. (look up "bowman weed chopper")

** Posted from **

Many of these small net appliances use low voltage AC or DC for power, not a wide-range AC supply. Thinking of what we call "wall warts" here in the US. The OP indicated it needed 12 V DC. I think he plans to supply the 12 V DC directly to the device, without going back up to mains voltage first.

Jon

Indeed. AC up, convert to dc to avoid the losses

Gunner

Political Correctness is a doctrine fostered by a delusional, illogical liberal minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Or scrounge around for a couple spools of military surplus "field phone" wire.

Really tough stuff and may simply be stapled to the fence posts. Will lasts for many many years in the sun, and is easily repaired.

Though..sheep may find it tastey..no idea.

Gunner

Political Correctness is a doctrine fostered by a delusional, illogical liberal minority, and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end.

Except for the ringing. IIRC, 50,60,70 hz were used to ring the bell on party line phones.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

Some learn by reading. Some learn by watching. Some just have to pee on the electric fence themselves. ;)

The only real advantage to these High Voltage DC Interties is that the power grids on each end do not have to be in exact synchronization for the systems to exchange power Normal AC transmission lines require both ends to be following the same frequency standard.

It has to be several hundred miles before HVDC is cheaper, because of the cost of building the converter stations at the ends. We have one of these HVDC lines that terminates in Los Angeles and heads to the Oregon / Washington State border region to pickup on all the excess summer hydroelectric capacity in the region. And in the winter when they use a lot of electric heat and the rivers are running low, we ship power north.

With a HVDC Transmission line they can easily tie two different regional grids together that are not in lock-step with each other, since the converter plants at either end slave to their region's own grid frequency - they can even have a gross mis-match like a 50 Hz grid at one end and a 60 Hz grid at the other.

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Field wire has rather high resistance, might be higher than 4mm steel wire. Resistance doesn't matter much with field phones because the currents are miniscule. I think phones are designed to work with something like 600 ohm impedance.

That wire is tough because some of the conductors are material having considerably higher tensile strength than copper. Phos bronze maybe, don't recall.