Post by thread:[EE]: finding underground cables

There is a standard scheme if the line is not broken. At one side of the cable a 50 to 100W audio power amplifier is sending on line 1kHz low frequency modulated signal. The other end of the line is short scurtcircuited. The receiver is a coil, an audio preamplifier and a pair of headphones on your ears. The biggest problem is if you have an iron pipe near your undergrown line, the effect is you go on pipe and not on cable... because of parasytic inductions. From my experience, founding lost cables is a nasty job. top 10 wishes, Vasile http://surducan.netfirms.com On Thu, 7 Aug 2003, Reelf Monsees wrote: {Quote hidden}> Hi, > I've got the 'nice' task of finding some underground communication- > cables in an area that is now overgrown with trees, shrubbs etc. Some > of the connection-boxes that connected the different cables are > missing / destroyed. The area measures about 100 square-kilometers, > so starting to dig in order to search for the cables is pointless. > There are devices that transmit signals into these cables and receivers > that detect the signal spreading out along these cables. > Does anybody have some ideas or even schematics for a transmitter > and receiver ? > > regards, > Reelf > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

That's something to start with. The problem is, that most of the cables are broken or the connection-boxes have been destroyed and the end of the cables are somewhere in the ground underneath earth, gravel, bits of stone and concrete where houses have been before. So inducing a signal into one end (we know where the cables begin) would be the best idea. regards, Reelf Vasile Surducan schrieb: {Quote hidden}> > There is a standard scheme if the line is not broken. > At one side of the cable a 50 to 100W audio power amplifier is sending > on line 1kHz low frequency modulated signal. The other end of the line is > short scurtcircuited. The receiver is a coil, an audio preamplifier and > a pair of headphones on your ears. > The biggest problem is if you have an iron pipe near your > undergrown line, the effect is you go on pipe and not on cable... > because of parasytic inductions. > >From my experience, founding lost cables is a nasty job. > > top 10 wishes, > Vasile > http://surducan.netfirms.com > > On Thu, 7 Aug 2003, Reelf Monsees wrote: > > > Hi, > > I've got the 'nice' task of finding some underground communication- > > cables in an area that is now overgrown with trees, shrubbs etc. Some > > of the connection-boxes that connected the different cables are > > missing / destroyed. The area measures about 100 square-kilometers, > > so starting to dig in order to search for the cables is pointless. > > There are devices that transmit signals into these cables and receivers > > that detect the signal spreading out along these cables. > > Does anybody have some ideas or even schematics for a transmitter > > and receiver ? > > > > regards, > > Reelf > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > > > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- SyWiTec * Systeme für Wissenschaft und Technik Bamberg & Monsees GbR Steindamm 22 * D-28719 Bremen Fon +49-421-646775 * Fax +49-421-646785 http://www.sywitec.de/ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

You might have good results with a simple metal detector. As you pick up the metal in the wire, walk down in each direction to plot its extent. Most cables, even power cables, are only buried a foot or two down. All Electronics has an eddy-current type "treasure" detector, for $37 USD, http://www.allelectronics.com , I think. --Bob At 12:41 PM 8/7/2003 +0200, you wrote: {Quote hidden}>Hi, >I've got the 'nice' task of finding some underground communication- >cables in an area that is now overgrown with trees, shrubbs etc. Some >of the connection-boxes that connected the different cables are >missing / destroyed. The area measures about 100 square-kilometers, >so starting to dig in order to search for the cables is pointless. >There are devices that transmit signals into these cables and receivers >that detect the signal spreading out along these cables. >Does anybody have some ideas or even schematics for a transmitter >and receiver ? > >regards, > Reelf > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Hm, also thought about that. Maybe I could induce a signal into the cable anyway and use a search-coil to pick up the signal. Building a search-coil with an amplifier (filtered input of course, so only the frequency of the induced signal is amplified) is not a problem. Any idea how to induce a signal into the cable ? Could be done inductive or direct as all cables are switched off. regards, Reelf Bob Axtell schrieb: {Quote hidden}> > You might have good results with a simple metal detector. As you pick up > the metal in the wire, walk down in each direction to plot its extent. Most > cables, even power cables, are only buried a foot or two down. All > Electronics has an eddy-current type "treasure" detector, for $37 USD, > http://www.allelectronics.com , I think. > > --Bob > > At 12:41 PM 8/7/2003 +0200, you wrote: > >Hi, > >I've got the 'nice' task of finding some underground communication- > >cables in an area that is now overgrown with trees, shrubbs etc. Some > >of the connection-boxes that connected the different cables are > >missing / destroyed. The area measures about 100 square-kilometers, > >so starting to dig in order to search for the cables is pointless. > >There are devices that transmit signals into these cables and receivers > >that detect the signal spreading out along these cables. > >Does anybody have some ideas or even schematics for a transmitter > >and receiver ? > > > >regards, > > Reelf > > > >-- > >http://www.piclist.com hint: The PICList is archived three different > >ways. See http://www.piclist.com/#archives for details. > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- SyWiTec * Systeme für Wissenschaft und Technik Bamberg & Monsees GbR Steindamm 22 * D-28719 Bremen Fon +49-421-646775 * Fax +49-421-646785 http://www.sywitec.de/ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Well, that MIGHT work, actually. I'd induce a very powerful signal at about 60khz. Several sites on the web indicate that 50khz-75Khz seems to propagate through rock and earth pretty well (search for CAVE RADIO links). --Bob At 02:35 PM 8/7/2003 +0200, you wrote: {Quote hidden}>Hm, also thought about that. Maybe I could induce a signal into >the cable anyway and use a search-coil to pick up the signal. >Building a search-coil with an amplifier (filtered input of course, >so only the frequency of the induced signal is amplified) is not a >problem. Any idea how to induce a signal into the cable ? Could be >done inductive or direct as all cables are switched off. > >regards, > Reelf > >Bob Axtell schrieb: > > > > You might have good results with a simple metal detector. As you pick up > > the metal in the wire, walk down in each direction to plot its extent. Most > > cables, even power cables, are only buried a foot or two down. All > > Electronics has an eddy-current type "treasure" detector, for $37 USD, > > http://www.allelectronics.com , I think. > > > > --Bob > > > > At 12:41 PM 8/7/2003 +0200, you wrote: > > >Hi, > > >I've got the 'nice' task of finding some underground communication- > > >cables in an area that is now overgrown with trees, shrubbs etc. Some > > >of the connection-boxes that connected the different cables are > > >missing / destroyed. The area measures about 100 square-kilometers, > > >so starting to dig in order to search for the cables is pointless. > > >There are devices that transmit signals into these cables and receivers > > >that detect the signal spreading out along these cables. > > >Does anybody have some ideas or even schematics for a transmitter > > >and receiver ? > > > > > >regards, > > > Reelf > > > > > >-- > > >http://www.piclist.com hint: The PICList is archived three different > > >ways. See http://www.piclist.com/#archives for details. > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > >-- >SyWiTec * Systeme für Wissenschaft und Technik > Bamberg & Monsees GbR > Steindamm 22 * D-28719 Bremen > Fon +49-421-646775 * Fax +49-421-646785 > http://www.sywitec.de/ > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. --------------- NOTICE 1. This account can accept email & attachments up to 10M in size. 2. Federal Monitors: At request of client, some attachments are encrypted. Please DO NOT delay traffic; please reply with credentials for password. -------------- -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

okay, also found some hints that indicate that 33 kHz to 133 kHz is a good range. No problem in generating the signal. But now it comes to coupling it to the cable. What would be best, using two cores of the cable (up to 140 of them in one cable) or the cores and ground ? And how would the coupling be done ? As the state of the other end of the cable is unknown, it can't be assumed that we get a current flowing. regards, Reelf Bob Axtell schrieb: {Quote hidden}> > Well, that MIGHT work, actually. I'd induce a very powerful signal at about > 60khz. Several sites on the web indicate that 50khz-75Khz seems to > propagate through rock and earth pretty well (search for CAVE RADIO links). > > --Bob > > At 02:35 PM 8/7/2003 +0200, you wrote: > >Hm, also thought about that. Maybe I could induce a signal into > >the cable anyway and use a search-coil to pick up the signal. > >Building a search-coil with an amplifier (filtered input of course, > >so only the frequency of the induced signal is amplified) is not a > >problem. Any idea how to induce a signal into the cable ? Could be > >done inductive or direct as all cables are switched off. > > > >regards, > > Reelf > > > >Bob Axtell schrieb: > > > > > > You might have good results with a simple metal detector. As you pick up > > > the metal in the wire, walk down in each direction to plot its extent. Most > > > cables, even power cables, are only buried a foot or two down. All > > > Electronics has an eddy-current type "treasure" detector, for $37 USD, > > > http://www.allelectronics.com , I think. > > > > > > --Bob > > > > > > At 12:41 PM 8/7/2003 +0200, you wrote: > > > >Hi, > > > >I've got the 'nice' task of finding some underground communication- > > > >cables in an area that is now overgrown with trees, shrubbs etc. Some > > > >of the connection-boxes that connected the different cables are > > > >missing / destroyed. The area measures about 100 square-kilometers, > > > >so starting to dig in order to search for the cables is pointless. > > > >There are devices that transmit signals into these cables and receivers > > > >that detect the signal spreading out along these cables. > > > >Does anybody have some ideas or even schematics for a transmitter > > > >and receiver ? > > > > > > > >regards, > > > > Reelf > > > > > > > >-- > > > >http://www.piclist.com hint: The PICList is archived three different > > > >ways. See http://www.piclist.com/#archives for details. > > > > > > -- > > > http://www.piclist.com hint: The PICList is archived three different > > > ways. See http://www.piclist.com/#archives for details. > > > >-- > >SyWiTec * Systeme für Wissenschaft und Technik > > Bamberg & Monsees GbR > > Steindamm 22 * D-28719 Bremen > > Fon +49-421-646775 * Fax +49-421-646785 > > http://www.sywitec.de/ > > > >-- > >http://www.piclist.com hint: The PICList is archived three different > >ways. See http://www.piclist.com/#archives for details. > > --------------- > NOTICE > > 1. This account can accept email & attachments up to 10M in size. > 2. Federal Monitors: At request of client, some attachments are encrypted. > Please DO NOT delay traffic; please reply with credentials for password. > -------------- > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- SyWiTec * Systeme für Wissenschaft und Technik Bamberg & Monsees GbR Steindamm 22 * D-28719 Bremen Fon +49-421-646775 * Fax +49-421-646785 http://www.sywitec.de/ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

There is a methode called "burning a cable". Is often used in 10KV and 30KV underground cables. When a cable have a bad isolation between a phase wire and the iron mantle, it's applied a short high voltage/energy pulse which is making a shortcircuit in the defective place. Then a higher current flows through the cable till that place. But if the cable haven't an iron mantle ? maybe a pulse between two wires? On Thu, 7 Aug 2003, Reelf Monsees wrote: {Quote hidden}> okay, also found some hints that indicate that 33 kHz to 133 kHz is > a good range. No problem in generating the signal. But now it comes > to coupling it to the cable. What would be best, using two cores of > the cable (up to 140 of them in one cable) or the cores and ground ? > And how would the coupling be done ? As the state of the other end > of the cable is unknown, it can't be assumed that we get a current > flowing. > > regards, > Reelf > > > Bob Axtell schrieb: > > > > Well, that MIGHT work, actually. I'd induce a very powerful signal at about > > 60khz. Several sites on the web indicate that 50khz-75Khz seems to > > propagate through rock and earth pretty well (search for CAVE RADIO links). > > > > --Bob > > > > At 02:35 PM 8/7/2003 +0200, you wrote: > > >Hm, also thought about that. Maybe I could induce a signal into > > >the cable anyway and use a search-coil to pick up the signal. > > >Building a search-coil with an amplifier (filtered input of course, > > >so only the frequency of the induced signal is amplified) is not a > > >problem. Any idea how to induce a signal into the cable ? Could be > > >done inductive or direct as all cables are switched off. > > > > > >regards, > > > Reelf > > > > > >Bob Axtell schrieb: > > > > > > > > You might have good results with a simple metal detector. As you pick up > > > > the metal in the wire, walk down in each direction to plot its extent. Most > > > > cables, even power cables, are only buried a foot or two down. All > > > > Electronics has an eddy-current type "treasure" detector, for $37 USD, > > > > http://www.allelectronics.com , I think. > > > > > > > > --Bob > > > > > > > > At 12:41 PM 8/7/2003 +0200, you wrote: > > > > >Hi, > > > > >I've got the 'nice' task of finding some underground communication- > > > > >cables in an area that is now overgrown with trees, shrubbs etc. Some > > > > >of the connection-boxes that connected the different cables are > > > > >missing / destroyed. The area measures about 100 square-kilometers, > > > > >so starting to dig in order to search for the cables is pointless. > > > > >There are devices that transmit signals into these cables and receivers > > > > >that detect the signal spreading out along these cables. > > > > >Does anybody have some ideas or even schematics for a transmitter > > > > >and receiver ? > > > > > > > > > >regards, > > > > > Reelf > > > > > > > > > >-- > > > > >http://www.piclist.com hint: The PICList is archived three different > > > > >ways. See http://www.piclist.com/#archives for details. > > > > > > > > -- > > > > http://www.piclist.com hint: The PICList is archived three different > > > > ways. See http://www.piclist.com/#archives for details. > > > > > >-- > > >SyWiTec * Systeme für Wissenschaft und Technik > > > Bamberg & Monsees GbR > > > Steindamm 22 * D-28719 Bremen > > > Fon +49-421-646775 * Fax +49-421-646785 > > > http://www.sywitec.de/ > > > > > >-- > > >http://www.piclist.com hint: The PICList is archived three different > > >ways. See http://www.piclist.com/#archives for details. > > > > --------------- > > NOTICE > > > > 1. This account can accept email & attachments up to 10M in size. > > 2. Federal Monitors: At request of client, some attachments are encrypted. > > Please DO NOT delay traffic; please reply with credentials for password. > > -------------- > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > > -- > SyWiTec * Systeme für Wissenschaft und Technik > Bamberg & Monsees GbR > Steindamm 22 * D-28719 Bremen > Fon +49-421-646775 * Fax +49-421-646785 > http://www.sywitec.de/ > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.

Yes, we have done that on other locations with energy-cables. The 'sparks' are audible with microphones touching the ground. Already though of that, but we can't do this here. Too dangerous as the sparks might cause not only damage to the cable but as some of the cables might end in a forrest or grass, we might cause serious fires. No rain for a long time, everything is dryed out. I'm just looking up the links for 'Cave Radio', maybe I can get some idea how to induce a strong enough signal into the cables. regards, Reelf Vasile Surducan schrieb: {Quote hidden}> > There is a methode called "burning a cable". Is often used in > 10KV and 30KV underground cables. When a cable have a bad isolation > between a phase wire and the iron mantle, it's applied a short high > voltage/energy pulse which is making a shortcircuit in the defective > place. Then a higher current flows through the cable till that place. > But if the cable haven't an iron mantle ? maybe a pulse between two > wires? > > On Thu, 7 Aug 2003, Reelf Monsees wrote: > > > okay, also found some hints that indicate that 33 kHz to 133 kHz is > > a good range. No problem in generating the signal. But now it comes > > to coupling it to the cable. What would be best, using two cores of > > the cable (up to 140 of them in one cable) or the cores and ground ? > > And how would the coupling be done ? As the state of the other end > > of the cable is unknown, it can't be assumed that we get a current > > flowing. > > > > regards, > > Reelf > > > > > > Bob Axtell schrieb: > > > > > > Well, that MIGHT work, actually. I'd induce a very powerful signal at about > > > 60khz. Several sites on the web indicate that 50khz-75Khz seems to > > > propagate through rock and earth pretty well (search for CAVE RADIO links). > > > > > > --Bob > > > > > > At 02:35 PM 8/7/2003 +0200, you wrote: > > > >Hm, also thought about that. Maybe I could induce a signal into > > > >the cable anyway and use a search-coil to pick up the signal. > > > >Building a search-coil with an amplifier (filtered input of course, > > > >so only the frequency of the induced signal is amplified) is not a > > > >problem. Any idea how to induce a signal into the cable ? Could be > > > >done inductive or direct as all cables are switched off. > > > > > > > >regards, > > > > Reelf > > > > > > > >Bob Axtell schrieb: > > > > > > > > > > You might have good results with a simple metal detector. As you pick up > > > > > the metal in the wire, walk down in each direction to plot its extent. Most > > > > > cables, even power cables, are only buried a foot or two down. All > > > > > Electronics has an eddy-current type "treasure" detector, for $37 USD, > > > > > http://www.allelectronics.com , I think. > > > > > > > > > > --Bob > > > > > > > > > > At 12:41 PM 8/7/2003 +0200, you wrote: > > > > > >Hi, > > > > > >I've got the 'nice' task of finding some underground communication- > > > > > >cables in an area that is now overgrown with trees, shrubbs etc. Some > > > > > >of the connection-boxes that connected the different cables are > > > > > >missing / destroyed. The area measures about 100 square-kilometers, > > > > > >so starting to dig in order to search for the cables is pointless. > > > > > >There are devices that transmit signals into these cables and receivers > > > > > >that detect the signal spreading out along these cables. > > > > > >Does anybody have some ideas or even schematics for a transmitter > > > > > >and receiver ? > > > > > > > > > > > >regards, > > > > > > Reelf > > > > > > > > > > > >-- > > > > > >http://www.piclist.com hint: The PICList is archived three different > > > > > >ways. See http://www.piclist.com/#archives for details. > > > > > > > > > > -- > > > > > http://www.piclist.com hint: The PICList is archived three different > > > > > ways. See http://www.piclist.com/#archives for details. > > > > > > > >-- > > > >SyWiTec * Systeme für Wissenschaft und Technik > > > > Bamberg & Monsees GbR > > > > Steindamm 22 * D-28719 Bremen > > > > Fon +49-421-646775 * Fax +49-421-646785 > > > > http://www.sywitec.de/ > > > > > > > >-- > > > >http://www.piclist.com hint: The PICList is archived three different > > > >ways. See http://www.piclist.com/#archives for details. > > > > > > --------------- > > > NOTICE > > > > > > 1. This account can accept email & attachments up to 10M in size. > > > 2. Federal Monitors: At request of client, some attachments are encrypted. > > > Please DO NOT delay traffic; please reply with credentials for password. > > > -------------- > > > > > > -- > > > http://www.piclist.com hint: The PICList is archived three different > > > ways. See http://www.piclist.com/#archives for details. > > > > -- > > SyWiTec * Systeme für Wissenschaft und Technik > > Bamberg & Monsees GbR > > Steindamm 22 * D-28719 Bremen > > Fon +49-421-646775 * Fax +49-421-646785 > > http://www.sywitec.de/ > > > > -- > > http://www.piclist.com hint: The PICList is archived three different > > ways. See http://www.piclist.com/#archives for details. > > > > -- > http://www.piclist.com hint: The PICList is archived three different > ways. See http://www.piclist.com/#archives for details. -- SyWiTec * Systeme für Wissenschaft und Technik Bamberg & Monsees GbR Steindamm 22 * D-28719 Bremen Fon +49-421-646775 * Fax +49-421-646785 http://www.sywitec.de/ -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.