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Locating underground conduit
On Fri, 17 Oct 2008 11:02:48 -0700, Jeff Liebermann
wrote: I should feel guilty for encouraging this off topic discussion, complete with topic drift, but I don't. Hi Jeff, I count it as adding value - even if it is for political education, sewer management (I didn't mean for that juxtaposition, but Karma seeks its own balance), and the parade of roses systems control. That photo was a blast. Did you actually have to cross your feet as part of the control heuristics? At the end of Stiglitz's discussion on the cost of the war ($3 to $5 Trillion at a minimum), someone asked plaintively "Don't you have something positive to offer us?" He responded "We will have a new president soon." 73's Richard Clark, KB7QHC |
Locating underground conduit
If you can run a metal 'snake' through that conduit, use a metal
detector to find the 'snake'. Ought'a be able to find a metal detector some where... - 'Doc (Tape a bottle cap to the end of that 'snake', they're easy to find.) |
Locating underground conduit
Do you know anyone who works with phone lines..Run a wire in the pvc and
hook a toner to one end & with the reciever you will here it & find the end....I have had to trace phone lines a few blocks long & underground also. They do work.... "Ed" wrote in message . 192.196... I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT |
Locating underground conduit
I reiterate:
Try stuffing your coax past the first 90 degree bend. If this won't work, you KNOW you will have to tear it all out again and redo it. |
Locating underground conduit - solved
My thanks to the entire group for the excellent responses (mostly :^) ) on my problem. It was only yesterday that I finally had opportunity to address it. The RF on the fish line did not work.... just did not seem to couple and radiate. However, a very very simple procedure ( one of you mentioned this ) did work. I had my wife pull and push the fish tape back and forth while I listened very closely for any sound of it thumping against the end of the pvc at the far end. It worked. I did not actually hear it hittingi the duct tape, but I did hear it as it moved back and forth on the last sweep at the end. It was only about 8 inches under the surface of the sand ( much less than I had thought ) and was located farily easily. You guys came up with a plethora of solutions which would have been fun to try.... one of the reasons I posted the question to this group, even though a bit off topic. To answer one question, the PVC will only be used for electrical, not antenna, so the 3/4" is quite sufficient for my needs. Again, thanks to all. I won't forget some of these methods suggested. Ed K7AAT |
Locating underground conduit - solved
Ed wrote:
"The RF on the fish line did not work." Problem is that loss is proportional to signal frequency through the earth, A low audio tone is much more appropriate. With a low audio tone on an insulated conductor buried in the earth with reference to a ground rod or ground bed, the conductor can be traced for miles. I`ve traced 4-ft. diameter poorly insulated steel pipelines for 8 miles or more and they were buried several feet down for protection. Reception can use a relay coil to sense the audio signal which is fed to an audio amplifier and earphones. The coil core points toward the conductor. From the angles made by the core on both sides of the conductor the depth of its cover can be closely estimated. Best regards, Richard Harrison, KB5WZI |
Locating underground conduit - solved
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Locating underground conduit - solved
Richard Clark wrote:
"These sounds were the RF emissions of lightning in the AF band." Richard also noted whistling sounds in army field telephones. I`ve seen these audio radiations called "whistlers". My efforts were to locate buried pipelines by a more convenient method than bouncing a metal pick off of them. Pipeline rights of way can be wide and pipes are often not where one may think but may be at odd distances from the center of the right of way. Connecting a signal to the pipe is much more effective than bouncing signals off the pipe or detuning a metal locator with the pipe. Another pipe tracing method in use is a vehicle (pig) launched into the pipe. The pig contains a pneumatic hammer which produces so much noise that it is easily heard through all the ground covering the pipe. Effective, but it is not cheap to launch and recover pigs. I`ve found broken pipes at the bottom of the Brazos River in Texas and around offshore platforms in the Gulf of Mexico. My efforts began with the availability of cheap SCR`s. I placed them to key the output of cathodic protection rectifiers at a low audio frequency rate. It worked well. For more portability, I constructed a complimentary symmetry bipolar power transistor generator which incorporated a 400-cycle Variac. The generator was adjusted to produce a 12-Hz switching rate which proved to work well. Output of the Variac was adjusted to give maximum power tnto the pipeline wherever it was used from the switched 12 V automobile battery. Connections to the pipeline are readily available at the cathodic protection test points at intervals of several miles all along the pipe. Best regards, Richard Harrison, KB5WZI |
Locating underground conduit
Jeff Liebermann wrote:
"---calibrating a pressure gauge to 10,000 PSI when the coupling line split sending a fine spray of pressurized oil past my face." I had a similar experience but at about 1/10 the pressure. It was exciting nonetheless. I was on watch in the engine room of an LSM in the middle of the Pacific during WW-2 and we were cruising at our usual 10 or 12 knots but alone, that is not in a convoy. We were equipped with (2) 1800 HP 10-cyl opposed piston Fairbanks Morse engines. To reverse an engine it is stopped then restarted with reversed rotation. This is accomplished by shifting the position of the camshaft within the engine with the engine controller. There is an automatically operated electric engine brake which clamps the engine shaft to stop its rotation during its rotation change. It has an enormous solenoid which holds the brake off while the engine is running but this can be defeated with a mechanical stop and a switch to save solenoid power if direction changes are unlikely. That`s how we were running to conserve power unescorted at sea. Suddenly the annunciator in front of me jinggled and ordered "Full Speed Astern". Without switching shaft brake power back on I complied. Suddenly the engine room was full of diesel oil mist, water mist, and smoke. I couldn`t imagine what had happened, but the engine started fine, thank you. in the reverse direction but I couldn`t see my hand in front of my face. After awhile, it dawned on me what had happened. Compresson pressure had fedback into the air compressor system blowing its pressure relief valve and filling the engine room with water from the compressor tank and diesel fuel from the engine cylinders. It was a mess but the exhaust air curculation soon cleared the atmosphere and no harm was done. Never again did I forget to enable the shaft brake before reversing engine directions. I was promoted to MoMM 3rd class and put in charge of my watch. My battle station was gun loader on the 40mm anti-aircraft guns. Best regards, Richard Harrison, KB5WZI |
Locating underground conduit - solved
Problem is that loss is proportional to signal frequency through the earth, A low audio tone is much more appropriate. With a low audio tone on an insulated conductor buried in the earth with reference to a ground rod or ground bed, the conductor can be traced for miles. I`ve traced 4-ft. diameter poorly insulated steel pipelines for 8 miles or more and they were buried several feet down for protection. Thats a suggestion that I would have liked to have tried. I have the generator, and could have easily fabricated a "receiver". Oh well. Another technique to add to the repertoire ! Ed K7AAT |
Locating underground conduit
On Fri, 17 Oct 2008 11:11:13 -0700, Richard Clark
wrote: ...and the parade of roses systems control. That photo was a blast. Did you actually have to cross your feet as part of the control heuristics? I'm slightly bow legged so crossing my feet is a more natural resting position. The resting position was very important at the start of the Rose Parade. The floats, horses, cars, etc all start getting organized at about 4AM. The parade starts at 8AM. The floats are never totally completed by New Year's day, so frantic last minute work at the starting point was normal. At this point, none of those involved have had more than one or two hours sleep, so a functional sleeping position is a basic requirement. I installed padding on top of the control panel for my feet. I think I only managed to get about 30 minutes of sleep before the unexpected happened. In 1968, we were behind an equestrian unit. After standing in essentially the same spot for about 3 hours, the horses deposited quite a pile of droppings on the pavement. There was a false start somewhat before 8AM. All the floats and horses lurched forward a few feet, placing our float directly over the pile. Besides the smell, the real worry was what would happen if the leaky hydraulic coupling mixed hot hydraulic fluid with horse dung. I was ready with a large fire extinguisher. Fortunately, nothing happened but we all nearly vomited from the stench. If you look a the photo: http://802.11junk.com/jeffl/pics/jeffl/slides/RoseFloat01.html you'll notice a large hinge point directly above my sleeping form. Part of the animation was a young boy, sleeping in bed, who raises up and scratches his eyes, when he sees the toys at the foot of the bed come alive. The kid was huge, thus the giant hinge. It worked fairly well throughout the parade. However, when drove the float back to Pomona for disassembly, it was discovered that all the 5/8"(???) bolts holding the boy to the hinge frame had halfway sheared through. This is the current animation system: http://cpprosefloat.org/site/page.php?23 In 1968, it was several partly insane students, flipping switches and toggling valves by hand. Cal Poly tended to win the animation prizes. To bring things back to ham radio antennas, we had a Motorola Breakie-Backie "portable" radio in the float on 2 meters. Tubes, vibrators, wet cells, and muscle. It sorta worked, but the chicken wire covering the float made a very effective shield. The antenna ended up hanging under the float as we didn't want it visible on top. Someone saw the "loose wire" and clipped it off just before the start of the parade. I made a replacement out of some baling wire. It worked, but about half way through the parade, the vibrator power supply quit. Oh well. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Locating underground conduit
Jeff Liebermann wrote:
On Fri, 17 Oct 2008 11:11:13 -0700, Richard Clark wrote: ...and the parade of roses systems control. That photo was a blast. Did you actually have to cross your feet as part of the control heuristics? To bring things back to ham radio antennas, we had a Motorola Breakie-Backie "portable" radio in the float on 2 meters. It's a challenge to put antennas on floats and meet the TORC requirements for only vegetable matter to be exposed. We got a special dispensation for our 23cm ATV from the JPL float. http://www.luxfamily.com/events/rose2005/roseatv.htm |
Locating underground conduit
On Tue, 21 Oct 2008 13:22:33 -0700, Jim Lux
wrote: Jeff Liebermann wrote: To bring things back to ham radio antennas, we had a Motorola Breakie-Backie "portable" radio in the float on 2 meters. It's a challenge to put antennas on floats and meet the TORC requirements for only vegetable matter to be exposed. We got a special dispensation for our 23cm ATV from the JPL float. http://www.luxfamily.com/events/rose2005/roseatv.htm Things sure have changed in 40 years. Nicely done float. How tall is it? We had stability problems with some of the floats. The parade route was fine, but entering Victory Park at the end was tricky. One year, some of the floats almost tipped over. Also, my fault tolerant memory has failed me once again. The snoozing photo of me is from of the 1970 float: http://cpprosefloat.org/site/plugins/autogallery/autogallery.php?show=7.Past%20Floats%2F350.1970.jp g The float consisted of 3 islands, connected with big long throw hydraulic rams. The float could be contracted to about 35 ft or extended to 59.99999 ft. The fun part was turning the Orange Grove to Colorado corner in front of the cameras, while simultaneously extending the float. Some officials didn't know which way the float was going to go and ran for cover. The sheared hinge bolts were from the 1971 float: http://cpprosefloat.org/site/plugins/autogallery/autogallery.php?show=7.Past%20Floats%2F340.1971.jp g It also features an elephant toy, with targeting controls for a small water pump and nozzle in the trunk. That was banned the following year. -- # Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060 # 831-336-2558 # http://802.11junk.com # http://www.LearnByDestroying.com AE6KS |
Locating underground conduit
On Tue, 21 Oct 2008 15:38:46 -0700, Jeff Liebermann
wrote: On Tue, 21 Oct 2008 13:22:33 -0700, Jim Lux wrote: Jeff Liebermann wrote: To bring things back to ham radio antennas, we had a Motorola Breakie-Backie "portable" radio in the float on 2 meters. It's a challenge to put antennas on floats and meet the TORC requirements for only vegetable matter to be exposed. We got a special dispensation for our 23cm ATV from the JPL float. http://www.luxfamily.com/events/rose2005/roseatv.htm Things sure have changed in 40 years. Nicely done float. How tall is it? We had stability problems with some of the floats. The parade route was fine, but entering Victory Park at the end was tricky. One year, some of the floats almost tipped over. Also, my fault tolerant memory has failed me once again. The snoozing photo of me is from of the 1970 float: http://cpprosefloat.org/site/plugins/autogallery/autogallery.php?show=7.Past%20Floats%2F350.1970.jp g The float consisted of 3 islands, connected with big long throw hydraulic rams. The float could be contracted to about 35 ft or extended to 59.99999 ft. The fun part was turning the Orange Grove to Colorado corner in front of the cameras, while simultaneously extending the float. Some officials didn't know which way the float was going to go and ran for cover. The sheared hinge bolts were from the 1971 float: http://cpprosefloat.org/site/plugins/autogallery/autogallery.php?show=7.Past%20Floats%2F340.1971.jp g It also features an elephant toy, with targeting controls for a small water pump and nozzle in the trunk. That was banned the following year. 70 & 71? Maybe you met Dave Steinfeld of TORRA . I worked with him for some years back in the day (80's). |
Locating underground conduit
On Tue, 21 Oct 2008 20:12:00 -0700, JosephKK
wrote: 70 & 71? Maybe you met Dave Steinfeld of TORRA . I worked with him for some years back in the day (80's). Nope. I don't recall the name. I only associated with radicals, leftists, protesters, anarchists, dissidents, draft dodgers, and a few engineers. If he was anything resembling a normal student, I probably didn't meet him. Also, I don't think that TORRA existed in 1971 and befo http://www.torra.us/id4.html There were very few active hams involved in construction of the floats at Cal Poly Pomona. I think there were only 2 or 3 electrical engineering students involved. At the time, the design and construction was dominated by Agricultural Business Mgmt students. It was easy to tell the difference. Engineers wore cowboy boots and ABM students wore suits, string ties, and carried brief a case. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Locating underground conduit
JosephKK wrote:
On Tue, 21 Oct 2008 15:38:46 -0700, Jeff Liebermann wrote: On Tue, 21 Oct 2008 13:22:33 -0700, Jim Lux wrote: Jeff Liebermann wrote: To bring things back to ham radio antennas, we had a Motorola Breakie-Backie "portable" radio in the float on 2 meters. It's a challenge to put antennas on floats and meet the TORC requirements for only vegetable matter to be exposed. We got a special dispensation for our 23cm ATV from the JPL float. http://www.luxfamily.com/events/rose2005/roseatv.htm Things sure have changed in 40 years. Nicely done float. How tall is it? We had stability problems with some of the floats. The parade route was fine, but entering Victory Park at the end was tricky. One year, some of the floats almost tipped over. Don't recall how tall it was, but it laid back down to get under the overpass at the end of the route. It was built by professional float builders (Phoenix) http://floatcam.caltech.edu/ has a link to video clips during construction, etc. 70 & 71? Maybe you met Dave Steinfeld of TORRA . I worked with him for some years back in the day (80's). Would that be WA6ZVE? He works in the RF Cal lab here at JPL. |
Locating underground conduit
On Wed, 22 Oct 2008 11:07:22 -0700, Jim Lux
wrote: Don't recall how tall it was, but it laid back down to get under the overpass at the end of the route. It was built by professional float builders (Phoenix) http://floatcam.caltech.edu/ has a link to video clips during construction, etc. My Real Media player is having its usual bad day. I'll look at it later. I forgot about the overpass. That would be a problem. One year, someone built a float over a large fork lift. The plan was to lower it at the overpass and again at the park entrance (due to overhanging wires). When the forks were lowered, the skin of the float was shredded. Someone used baling wire to tie together the ends of the chicken wire skin at the junction. Oops. Cal Poly traded space in the Rose Palace with D.E. Bent and Sons. I think he retired in about 1978. We supplied him with surplus labor (mostly for decorating and handling flowers) in trade for floor space and "borrowing" tools. It was a very professional operation. One of the funniest things was watching Disney Animation attempt to build their first animated float. Everyone expected big things from them due to their experience at Disneyland. As expected, the float had more moving parts than stationary. Just one problem; Disney ran on pneumatics instead of hydraulics. The centerpiece of their design was a rather large globe with a satellite spinning around it. The globe was bisected at the equator with a cantilever rod supporting the satellite. It, and other moving parts, sorta worked. Then, they added the flowers and watered them. That added lots of weight, which they hadn't expected. The support rod bent and had to be reinforced. Instead of smoothly orbiting the planet, the satellite lurched and jerked its way around the globe. The pneumatics could not overcome the added friction. The pressure just built up and up until the satellite suddenly lurched free. This was repeated every minute or so. I vaguely recall that it finally died about half way through the parade when some hose or fitting finally broke from the concussions. By then, all the flowers had been catapulted off anyway. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Locating underground conduit
On Oct 15, 1:17*am, Ed wrote:
* *I know this is slightly off topic, *but since I am intending to run some RF cable in the conduit, *and since there are a lot of intelligent hams on this group, *I will proceed anyway: * *Last year at the beginning of construction of a new house I buried about 50 feet of *3/4" Sched. 40 PVD between the house and a location on the property perimeter. * Now that I am ready to use it, *I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. * * The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. * * The end terminated in an elbow curving up and is well duct taped shut. * * Can anyone suggest a method or equipment I might use to locate that far end? * * Tnx. * *Ed * K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie |
Locating underground conduit
"JIMMIE" wrote in message ... On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie Hi Jimmie That "air" idea wont work, Jeff told me so Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics Ok, let's do the math. Dry sand weighs 100 lb/cubic-foot. There's about 1 ft of sand above the end of the 3/4" conduit. The weight action is roughly conical, so the volume of sand involved is (my guess) about: 100 lbs/ft^3 * 1/3 = 33 lbs of sand. All that it acting on a 3/4" diameter pipe, with a cross sectional area of about: Pi * 0.75" = 2.4 in^2 Therefore, the pressure exerted by the sand is: 33 lbs / 2.4 in^2 = 14 PSI So, if he can pressurize the pipe to more than 14 PSI, he can lift the column of sand sufficiently to keep it from dribbling into the pipe. Of course, it's not that simple. Laminar air flow, pressure gradients across the conduit, and the effects of the duct tape will ruin my simplistic guesswork. Worse, the back pressure created by the immovable column of sand will force some sand particles into the conduit around the edges with the "reflected" air pressure. In the middle of the conduit, the air flow is all out of the conduit, but near the edges, it could easily be the other direction. I'm also assuming that the sand is a perfect air seal, which it's not. To prevent all this from happening, the minimum air pressure should be about twice the 14 PSI, which is easily achievable with an air compressor, but not a vacuum cleaner. I'm also trying to imagine how the process will work. I see an air compressor pumping madly away as the neighbors kids furiously dig around the resultant sand volcano, as sand rapidly refills the conical hole. In my never humble opinion, there's no way to prevent sand from dropping into the conduit if the duct tape seal is broken before excavating the end of the conduit. Once the sand is in the conduit, just blowing air through the pipe isn't going to magically elevate the sand particles 1ft or more in the air. The air does not have sufficient mass to convey enough momentum to move the sand particles, much less eject them vertically. For that, one needs a denser medium, such as water. Shoving a plunger through might work, but it's equally likely to jam sand particles into the PVC conduit walls. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558" Jerry KD6JDJ |
Locating underground conduit
Jerry wrote:
"JIMMIE" wrote in message ... On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie Hi Jimmie That "air" idea wont work, Jeff told me so Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics It can work, because what you are trying to do is not to move a lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. - 73 de Mike N3LI - |
Locating underground conduit
It can work, because what you are trying to do is not to move a lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. Yes, making noise was key in locating my underground PVC. In my case, I was able to locate the end by listening closely NEAR where I thought it should have been while someone else was running a snake fully inserted in the pvc back and forth a few inches.... the noise it made at the last sweep was evident with no other background noise to interfere with it. Ed K7AAT |
Locating underground conduit
Ed wrote:
It can work, because what you are trying to do is not to move a lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. Yes, making noise was key in locating my underground PVC. In my case, I was able to locate the end by listening closely NEAR where I thought it should have been while someone else was running a snake fully inserted in the pvc back and forth a few inches.... the noise it made at the last sweep was evident with no other background noise to interfere with it. And if Jimmie will let us borrow his dog, we'll be all set! - 73 de Mike N3LI - |
Locating underground conduit
After making a post early on this topic, what goes around came around
and I had to identify a coax that passed under the driveway... Ye old wire tracer and 30 seconds is all it took to find it... denny - k8do |
Locating underground conduit
On Oct 23, 12:02*am, "Jerry" wrote:
"JIMMIE" wrote in message ... On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. *To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie * Hi Jimmie * That "air" idea wont work, Jeff told me so * Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics Ok, let's do the math. *Dry sand weighs 100 lb/cubic-foot. *There's about 1 ft of sand above the end of the 3/4" conduit. *The weight action is roughly conical, so the volume of sand involved is (my guess) about: * 100 lbs/ft^3 * 1/3 = 33 lbs of sand. All that it acting on a 3/4" diameter pipe, with a cross sectional area of about: * Pi * 0.75" = 2.4 in^2 Therefore, the pressure exerted by the sand is: * 33 lbs / 2.4 in^2 = 14 PSI So, if he can pressurize the pipe to more than 14 PSI, he can lift the column of sand sufficiently to keep it from dribbling into the pipe. Of course, it's not that simple. *Laminar air flow, pressure gradients across the conduit, and the effects of the duct tape will ruin my simplistic guesswork. *Worse, the back pressure created by the immovable column of sand will force some sand particles into the conduit around the edges with the "reflected" air pressure. *In the middle of the conduit, the air flow is all out of the conduit, but near the edges, it could easily be the other direction. *I'm also assuming that the sand is a perfect air seal, which it's not. *To prevent all this from happening, the minimum air pressure should be about twice the 14 PSI, which is easily achievable with an air compressor, but not a vacuum cleaner. I'm also trying to imagine how the process will work. *I see an air compressor pumping madly away as the neighbors kids furiously dig around the resultant sand volcano, as sand rapidly refills the conical hole. *In my never humble opinion, there's no way to prevent sand from dropping into the conduit if the duct tape seal is broken before excavating the end of the conduit. Once the sand is in the conduit, just blowing air through the pipe isn't going to magically elevate the sand particles 1ft or more in the air. *The air does not have sufficient mass to convey enough momentum to move the sand particles, much less eject them vertically. *For that, one needs a denser medium, such as water. *Shoving a plunger through might work, but it's equally likely to jam sand particles into the PVC conduit walls. -- Jeff Liebermann * * 150 Felker St #D * *http://www.LearnByDestroying.com Santa Cruz CA 95060http://802.11junk.com Skype: JeffLiebermann * * AE6KS * *831-336-2558" * * * * *Jerry * KD6JDJ- Hide quoted text - - Show quoted text - Obviously you're an engineer. LOL Jimmie |
Locating underground conduit
"Michael Coslo" wrote in message
... Jerry wrote: "JIMMIE" wrote in message ... On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie Hi Jimmie That "air" idea wont work, Jeff told me so Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics It can work, because what you are trying to do is not to move a lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. And where is the air going to escape? He said he duct-taped the end shut. With enough pressure, he'll have a blow-out, but that could also result in getting dirt inside the pipe, which I believe wouldn't be good. However, short of that, there's no hole for the air make noise.... He knows the length and direction. He should be able to make an educated guess as where to dig. |
Locating underground conduit
"D. Stussy" wrote in message ... "Michael Coslo" wrote in message ... Jerry wrote: "JIMMIE" wrote in message ... On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie Hi Jimmie That "air" idea wont work, Jeff told me so Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics It can work, because what you are trying to do is not to move a lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. And where is the air going to escape? He said he duct-taped the end shut. With enough pressure, he'll have a blow-out, but that could also result in getting dirt inside the pipe, which I believe wouldn't be good. However, short of that, there's no hole for the air make noise.... He knows the length and direction. He should be able to make an educated guess as where to dig. Hi D You and Jeff may know something I didnt realize about sealing. I cant imagine being able to make duct tape seal off the open end of a PVC pipe with tuct tape, How much pressure can be sealed with the tape on the side of the PVC? I would have expected the tape to have been applied to prevent sand from entering. That wouldnt seal against much air pressure. Furthermore, it is very easy to apply only adequate pressure to initiate some air flow , not a sudden blast at high pressure to cause a crater. As you know, a small amount of air flowing thru a small passage can produce plenty of sound. You are right, he has found the end of the pipe. I am curious to know why it is necessary to write that the air leak method *wont* work when I am sure it will work, Jimmy has demonstrated that. Jerry |
Locating underground conduit
On Oct 23, 7:02*pm, "Jerry" wrote:
"D. Stussy" wrote in message ... "Michael Coslo" wrote in message ... Jerry wrote: "JIMMIE" wrote in message .... On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. *To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie * Hi Jimmie * That "air" idea wont work, Jeff told me so * Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics It can work, because what you are trying to do is not to move a * lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. And where is the air going to escape? *He said he duct-taped the end shut. With enough pressure, he'll have a blow-out, but that could also result in getting dirt inside the pipe, which I believe wouldn't be good. *However, short of that, there's no hole for the air make noise.... He knows the length and direction. *He should be able to make an educated guess as where to dig. * Hi D * You and Jeff may know something I didnt realize about sealing. * I cant imagine being able to make duct tape seal off the open end of a PVC pipe with tuct tape, * How much pressure can be *sealed with the tape on the side of the PVC? * I would have expected the tape to have been applied to prevent sand from entering. That wouldnt seal against much air pressure. Furthermore, it is very easy to apply only adequate pressure to initiate some air flow , not a sudden blast at high pressure to cause a crater. *As you know, a small amount of air flowing thru a small passage can produce plenty of sound. * You are right, he has found the end of the pipe. * I am curious to know why it is necessary to write that the air leak method *wont* work when I am sure it will work, Jimmy has demonstrated that. * * * * * * * *Jerry - Hide quoted text - - Show quoted text -- Hide quoted text - - Show quoted text - I must admit that sand could get into the pipe but I cant see that would be all that bad. My pipe had water in it that is really why I was able to find it. If i want to clean it out I would just blow some strips of cloth through it or in the case of sand rinse it out with water then dry it out with warm air. Shop vacs are great for this. I should have left the damned thing alone. Now my wife wants me to finish putting in the spigot. She gave me a Thanksgiving suspense date. Jimmie |
Locating underground conduit
"Jerry" wrote in message
... "D. Stussy" wrote in message ... "Michael Coslo" wrote in message ... Jerry wrote: "JIMMIE" wrote in message ... On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie Hi Jimmie That "air" idea wont work, Jeff told me so Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics It can work, because what you are trying to do is not to move a lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. And where is the air going to escape? He said he duct-taped the end shut. With enough pressure, he'll have a blow-out, but that could also result in getting dirt inside the pipe, which I believe wouldn't be good. However, short of that, there's no hole for the air make noise.... He knows the length and direction. He should be able to make an educated guess as where to dig. Hi D You and Jeff may know something I didnt realize about sealing. I cant imagine being able to make duct tape seal off the open end of a PVC pipe with tuct tape, How much pressure can be sealed with the tape on the side of the PVC? I would have expected the tape to have been applied to prevent sand from entering. That wouldnt seal against much air pressure. Furthermore, it is very easy to apply only adequate pressure to initiate some air flow , not a sudden blast at high pressure to cause a crater. As you know, a small amount of air flowing thru a small passage can produce plenty of sound. You are right, he has found the end of the pipe. I am curious to know why it is necessary to write that the air leak method *wont* work when I am sure it will work, Jimmy has demonstrated that. Well, let's see: 3/4" pipe, and duct tape is usually 2" wide. That means the entire end will be covered with a single piece with its sides folded down. Duct tape is designed NOT to let air pass. That means there's a good chance that the seal was air-tight. |
Locating underground conduit
Yes, making noise was key in locating my underground PVC. In my
case, I was able to locate the end by listening closely NEAR where I thought it should have been while someone else was running a snake fully inserted in the pvc back and forth a few inches.... the noise it made at the last sweep was evident with no other background noise to interfere with it. Ed K7AAT Congrats! That's probably the best answer, as you are going to fish something or not and it's always more expedient to use the most handy tool first before hauling out the hardware store or the drawing board. This is how it usually plays out, that there is plenty of noise when you are trying to bang the fishtape past the 90's. This is how I learned to use 45 degree sweeps and pull boxes at every opportunity. Anything to avoid the frustration of breaking wire or fish tape and wasting my own time. |
Locating underground conduit
You and Jeff may know something I didnt realize about sealing. I cant imagine being able to make duct tape seal off the open end of a PVC pipe with tuct tape, How much pressure can be sealed with the tape on the side of the PVC? I would have expected the tape to have been applied to prevent sand from entering. That wouldnt seal against much air pressure. For the record, I duct taped the end well, when it was initially buried, in order to keep out sand and even water. It was applied well enough to prevent any reasonable air pressure from moving it, in my opinion. Duct Tape is awful sturdy stuff, and sticks quite well, too. As I already said earlier, a bunch of you guys posted some excellent ideas I could have used.... and I probably would have if my first simple try with making noise with my fish tape hadn't worked. Thanks again to all. Ed K7AAT |
Locating underground conduit
"D. Stussy" wrote in
: "Michael Coslo" wrote in message ... Jerry wrote: "JIMMIE" wrote in message . .. On Oct 15, 1:17 am, Ed wrote: I know this is slightly off topic, but since I am intending to run some RF cable in the conduit, and since there are a lot of intelligent hams on this group, I will proceed anyway: Last year at the beginning of construction of a new house I buried about 50 feet of 3/4" Sched. 40 PVD between the house and a location on the property perimeter. Now that I am ready to use it, I can not locate the perimeter end.... it is somewhere in about a 10' area, and the end curves up to probably about a foot underground. The ground is nearly pure sand, and is well landscaped now to the point that I do not want to randomly dig it up. The end terminated in an elbow curving up and is well duct taped shut. Can anyone suggest a method or equipment I might use to locate that far end? Tnx. Ed K7AAT I have some pipe that I had run for an outdoor spigot that I never finished installing. To test a method of finding it I shot some air into it the other end was pretty easy to find by listening. I could hear the rush of air and a lot of gurgling. My dog actually found it in the roses bushes before I did. Jimmie Hi Jimmie That "air" idea wont work, Jeff told me so Quote Jeff -- "Welcome to rec.radio.amateur.antenna.physics It can work, because what you are trying to do is not to move a lot of air and sand, but try to make some noise. And you don't have to move a whole lot of sand to do that. As long as the pipes stay together, some air will make it out of the open end and make some noise. And where is the air going to escape? He said he duct-taped the end shut. With enough pressure, he'll have a blow-out, but that could also result in getting dirt inside the pipe, which I believe wouldn't be good. However, short of that, there's no hole for the air make noise.... He knows the length and direction. He should be able to make an educated guess as where to dig. That duct tape isn't at all likely to seal the pipe; some air will escape - One of the reason's we don't repair flat tires with duct tape. 8^) As an example of sound traveling underground, here in the battleground state of PA, there are a lot of places where there are streams underground. A tiny trickle of water can be heard even by my bad ears, several feet underground. - 73 de Mike N3LI |
Locating underground conduit
As an example of sound traveling underground, here in the battleground state of PA, there are a lot of places where there are streams underground. A tiny trickle of water can be heard even by my bad ears, several feet underground. One little thing in my situation, we're about 1/3 mile away from the Pacific North West Ocean surf and believe me, it is genearlly quite loud.... enough to preclude hearing delicate sounds in the soil at times. It took a relatively quiet day just to hear the fish tape rattling. Ed :^) |
Locating underground conduit
On Wed, 22 Oct 2008 11:07:22 -0700, Jim Lux
wrote: JosephKK wrote: On Tue, 21 Oct 2008 15:38:46 -0700, Jeff Liebermann wrote: On Tue, 21 Oct 2008 13:22:33 -0700, Jim Lux wrote: Jeff Liebermann wrote: To bring things back to ham radio antennas, we had a Motorola Breakie-Backie "portable" radio in the float on 2 meters. It's a challenge to put antennas on floats and meet the TORC requirements for only vegetable matter to be exposed. We got a special dispensation for our 23cm ATV from the JPL float. http://www.luxfamily.com/events/rose2005/roseatv.htm Things sure have changed in 40 years. Nicely done float. How tall is it? We had stability problems with some of the floats. The parade route was fine, but entering Victory Park at the end was tricky. One year, some of the floats almost tipped over. Don't recall how tall it was, but it laid back down to get under the overpass at the end of the route. It was built by professional float builders (Phoenix) http://floatcam.caltech.edu/ has a link to video clips during construction, etc. 70 & 71? Maybe you met Dave Steinfeld of TORRA . I worked with him for some years back in the day (80's). Would that be WA6ZVE? He works in the RF Cal lab here at JPL. That call sign sounds right. The home / station address matches the lookup to my address book. That is a good enough match for me. |
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