In Need of tone genertor/cable tracer

I need to trace some cables (phone catv, ethernet) throughout a house. An inexpensive tone generator would work but I don't have one. Any recomme ndations for an inexpensive one? or alternatives? I rigged a 1.5V battery holder with alligator clips to be used in conjunction with a modified LED ' probe' flashlight which will work. Looking for alternative ideas. I did make a 'break out box' for the rj45 and rj11 sockets where needed. Thanks j

Reply to
three_jeeps
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If you have an old portable AM radio you can whip up an electrical noise/spark generator that you hook to one end of the wire then track it through the house using the radio.

Not so many hand held radios lying around these days though...

John :-#)#

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Reply to
John Robertson

At work, we have a device that works like that. It contains a kind of AM radio at one end and a simple "transmitter" (AM modulated generator) for the other end. You clip the transmit side to a cable and it is able to detect the other end of the cable within like a 10cm (4") range.

It is intended to find connection points on MDF/LDF, network patch panels, etc etc.

Indeed it should be possible to build something like this yourself, or simply use a radio and a "short range AM transmitter" module.

Reply to
Rob

three_jeeps wrote: ===============

** Did you mean * identify* cables or find the actual path ?
** What would you do if you did?

Why not use a AA cell and an LED ?

...... Phil

Reply to
Phil Allison

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No further than your local big-box and/or Amazon.

Why go with a kluge when the real thing (and all the associated reliability thereto) is readily available?

Peter Wieck Melrose Park, PA

Reply to
Peter W.

How far would that read?

Power to my shed is underground, and I need to do some digging to fix some drainage. it would really help to know exactly where the 220 is routed. I suspect it's in the 6 to 8 inch deep range, given the slope, hopefully a little deeper some places. .

Reply to
Tim R

e drainage. it would really help to know exactly where the 220 is routed. I suspect it's in the 6 to 8 inch deep range, given the slope, hopefully a l ittle deeper some places. .

That is a low-voltage device, not for power lines. Underground cable tracer s are very different animals, and substantially more costly. if all you nee d to do is 6-8" or so, borrow a decent metal detector and trace that way. Y ou will be within inches - dig out that area by hand. In any case, do call your local One-Call service, it is free and often you have no idea of what may be down there. And they DO have the costly devices.

Peter Wieck Melrose Park, PA

Reply to
Peter W.

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$25 US

Works well tracing house wiring. Just remember to turn off ALL circuit breakers in the mains panel.

Reply to
Buddy

The minimum depth of buried power cable varies from 6 inches to perhaps 24 inches. This might help: If the power cables are inside a steel pipe, none of the RF or induction methods of wire location will work. However, a common metal detector will work quite nicely at detecting the pipe.

Maybe call 811 (in the USA)?

Maybe hire an underground utility location service?

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Jeff Liebermann                 jeffl@cruzio.com 
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Reply to
Jeff Liebermann

Around here you can go to miss utility on the web or call 811. They only do the commercial power, phone, cable and gas. If you have your own wire from the house to an outbuilding or well they will not do it.

It is a free service. I have used them twice. Once when I had some stumps ground up that had roots that extended out about 10 feet from the tree. Good thing I did as the underground power cable was under a small tree stump so I told the grinder man to only go low enough the lawn mower would not hit the stump. A year later when I had a garage bulit and the foundation needed to be dug. The man only did the power line the 2nd time. They were not going to come out when I filled out the web page, but I called them and told them I knew the power line was probably in the way. They marked the power line but not the cable line. Sure enough the cable line was cut as it was about 2 feet inside the garage foundation. Cable people replaced it at no charge as I had called the utility people.

Reply to
Ralph Mowery

No. "Designed for use with telephone lines, alarm cables, computer cables, intercom lines, speaker wires, and thermostat wiring."

Not line voltage. And not for underground tracing either.

Peter Wieck Melrose Park, PA

Reply to
Peter W.

But the question was "I need to trace some cables (phone catv, ethernet) throughout a house.". So what is your problem?

Reply to
Rob

Rob wrote: ========

** There are TWO different questions here from TWO posters. Pay attention.

..... Phil

Reply to
Phil Allison

Do you not read for content?

Peter Wieck Melrose Park, PA

Reply to
Peter W.

ome drainage. it would really help to know exactly where the 220 is routed. I suspect it's in the 6 to 8 inch deep range, given the slope, hopefully a little deeper some places. .

ers are very different animals, and substantially more costly. if all you n eed to do is 6-8" or so, borrow a decent metal detector and trace that way. You will be within inches - dig out that area by hand. In any case, do cal l your local One-Call service, it is free and often you have no idea of wha t may be down there. And they DO have the costly devices.

Sorry to confuse the thread with two different applications.

My thought was that if a signal generator can put a tone on my line, I coul d shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house. It seems like that should work if the wire is 6 inches down, maybe not if it's 18. Or maybe those t one generators don't work at all underground, I've never tried it. I did b orrow a metal detector some years ago but got inconclusive results. Maybe i could rent a better one from a big box or electrical place. I'm sure the there is no conduit, I hit a wire some years back that looked like UFB, so I know where at least one piece of it is, and it wasn't where I expected i t.

Reply to
Tim R

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** LOL - that is NOT what tone generators do !!

Their job is to facilitate cable *identification* where multiples exist.

OTOH a buried mains cable reveals it *location * by the magnetic field created by all the damn AC current flowing in it !!

..... Phil

Reply to
Phil Allison

This might help: "Buyers Guide To Cable Locators" There are some that work at 60 Hz, but most use higher frequencies. There's just too much interference at 60 Hz. Also, the higher the frequency, the higher the resolution, which translates in a more accurately located cable. "Successful Locating Depends on Knowing Which Frequency to Use"

More than you probably wanted to know: "The theory of buried cable and pipe location"

For what it's worth, I used an RF signal generator to locate buried cables. The trick is to build a series resonant RF transformer (ferrite torroid) for your choice of RF frequency. I picked the 160 meter ham band (1.8 to 2.0Mhz), much to the irritation of the local ham radio operators. The generator was set to about 70% AM modulation at 1KHz to produce a detectable tone. The resonant transformer will pass the RF but not the 60 Hz line frequency, thus insuring that there is some hope that the RF generator will survive the exercise. It also provides an ungrounded connection to the power line, which should prevent some types accidental electrocutions.

The difficult part was designing and building a suitable pickup coil. I finally resorted to a ferrite rod (loopstick) antenna similar to what is found in many SW (short wave) receivers. Such a loopstick antenna a nice deep null in the antenna pattern off the end of the rod, which makes direction finding possible.

If I were to design a cable locator today, the system would be quite different. The problem with using only one frequency is that various types of dirt attenuate different frequencies differently. Instead of one frequency, I would use a range of frequencies (spread spectrum), in the hope that at least one frequency will make it through the dirt (and interference). That's how ground penetrating radar works.

The last time I had to locate some underground wiring, I was lazy and used an acoustic method. I made a low frequency "buzzer" that ran from compressed air. I shoved the air hose as far up the PVC conduit as possible and turned on the buzzer. With a 1 HP motor, that might produce 200 watts of audible buzz, which should be audible at ground level. I used a stethoscope to locate the buried conduit. It wasn't very precise at locating the conduit, but good enough to provide clearance for a backhoe trencher.

Good luck.

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Jeff Liebermann                 jeffl@cruzio.com 
PO Box 272      http://www.LearnByDestroying.com 
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Reply to
Jeff Liebermann

Thanks for pointing out the inaccuracy of my post. My task is one of identification. I just bought an inexpensive one from one of the references. I'll use my flashlight arrangement as a backup. I did learn something from Jeff about cable locators - TY. Will file that away as I may be doing some of that in the future.

J
Reply to
three_jeeps

e:

I could shut the breaker in the house, leave the shed dead, put the signal on the shed end, and trace the wire back to the house.

.

created by all the damn AC current flowing in it !!

tification.

flashlight arrangement as a backup.

away as I may be doing some of that in the future.

Yes, I agree, thanks much for that link. There was much in there that had not occurred to me, especially about other current sources coupling to unde rground lines. It seems just possible though maybe not likely that I can f ind an AM radio or other device that will buzz a bit close to the line, and that the effect is larger if it's carrying a good current, worth a try any way. I'm pretty sure my line is shallow and maybe even DIY.

Reply to
Tim R

not occurred to me, especially about other current sources coupling to und erground lines. It seems just possible though maybe not likely that I can f ind an AM radio or other device that will buzz a bit close to the line, and that the effect is larger if it's carrying a good current, worth a try any way. I'm pretty sure my line is shallow and maybe even DIY.

This might be possible for an acutely sensitive device - and most AM radios are not that. some basics, and a few assumptions first:

a) The underground cable in question is either UF cable, or several conduct ors run in some sort of conduit. If the conduit is metallic, or otherwise s hielded, the AM radio trick will not work. b) This cable is in the US, and so is single-phase, 240 V, and consists of two (2) hots, one (1) neutral and one (1) ground per present code. I will n ot speculate on Euro/Aussie codes or cables. We do know also from Phil tha t electricity has unusual properties down under.

So, if the goal is to locate the cable so as not to dig through it, proof-o f-concept would suggest that if the target radio were to be placed near to say.... an active AC line cord inside, it should buzz. And it should start buzzing within 18" or more, at least. Given that most ground is at least a little-bit-damp, and so will do some shielding, and the depth is unknown, t his margin is needed.

Just a few thoughts - considering that if it were that simple, an undergrou nd power cable tracer would be a trivial device vs. their actual cost.

Peter Wieck Melrose Park, PA

Reply to
Peter W.

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