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Old October 26th 15, 05:30 PM posted to rec.radio.amateur.antenna
Jeff Liebermann[_2_] Jeff Liebermann[_2_] is offline
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First recorded activity by RadioBanter: Jun 2007
Posts: 1,336
Default Locating empty underground conduit

On Mon, 26 Oct 2015 07:36:00 -0700 (PDT),
wrote:

The conduit on both ends have been pressurized to 350 psi and held
the pressure for over 10 minutes. That would means to me that there
are no leaks unfortunately.


If the pipes were made from plastic, 350 PSI is enough to blow the
couplings and crack the sides out of the pipe. No leaks could also
mean that there's no continuity from end to end. When you say that it
"held pressure for over 10 mins", does that mean that the pressure
stayed at 350 psi with the compressor turned off, or that it took 10
minutes to leak down to 0 psi? If you are unable to see end to end
continuity with air pressure, then you will certainly not be able to
shove a snake down the pipe without hitting something blocking the
path. Or, there may not be a path. Also, If there really is a pull
box in mid path with hole plugs, your 350 PSI pressure test just blew
all the plugs out, which will later let water into the boxes. Pull
boxes are made to handle high pressure from the OUTSIDE (to keep water
out), not from the inside. Nice work. Also, how did you get 350 PSI
air? Most shop single stage air compressor will only do about 150 PSI
max.

I suggest you use the whistle trick from each end. If you have air
continuity from end to end, you should be able to easily hear the
whistle at the other end with a stethoscope. Depending on the depth
of the conduit and the construction, you should also be able to hear
it through the ground. (Some specifics on what materials you're
working with would be helpful). You may not be able to trace the
entire pipe, but you can at least get the general direction.

If you have money, rent an underground pipe locator. Shove your 100ft
snake through each end of the pipes, use that as an "antenna", and
follow the pipe lines. You'll be missing 100ft in the middle, but I
think you might be able to visually connect the dots.

Where can I find a radio transmitter that I can somehow get it
into the line? I cannot find a place that has a snake longer than 100'.
The contractors snaked the line themselves with a 200' snake on
both ends and theirs went in without a problem.


If the pipe is steel, you won't get any RF through it. There are low
frequency pipe finders that will go through dirt. However, they
require a tracer wire be buried with the conduit.
https://www.google.com/#q=underground+pipe+locator

I will also try contacting the town today to see if they have the
records, but from what I remember the BI saying, they only keep
records for 5 years.


How about a clue as to what you're working with?
Type of conduit pipe? Diameter? Depth of burial?
What's currently in the conduit?
Type of ground? Concrete overlay? Rocky? Water table?

--
Jeff Liebermann

150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558