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

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

On Mon, 20 Oct 2008 00:25:00 -0500, (Richard
Harrison) wrote:

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.

During WWI, Heinrich Barkhausen was working with army field telephones
that exhibited strange whistling sounds, unrelated to the war
communications. These sounds were the RF emissions of lightning in
the AF band. What is more interesting is that the mode of propagation
was along Earth's magnetic flux lines, and the scale of propagation
was hemispheric.

As a byproduct of this research, Barkhausen suggested subterranean
communication employing a widely separated pair of rods in the earth,
and driving them with audio frequency communications. Range was
reportedly a function of the distance between the rods. The receiver
used the same earth connection method.

This was the subject of a Popular Electronics article in the mid 60s.

Not reported in that journal, Beverage of antenna fame was working at
the same time trying to develop a reliable RF communication system for
sending orders to troops in the field in Europe, from the US. His
system was a ground level wire of several 10s of miles long, oriented
end-on towards Europe. Troops could hear the US broadcasts in the
field with unsophisticated equipment. However, transmissions back to
the US didn't fare as well. They were overwhelmed on receive by the
back side orientation of the long wire towards the Caribbean and its
summer electrical storms. Dr. Beverage solved that by extending the
wire in that direction too and with termination.

Those frequencies were easily 30 times, or more, higher than
Barkhausen's suggestion - hence the very looooooong wire.

73's
Richard Clark, KB7QHC

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

On Wed, 15 Oct 2008 20:58:55 -0700, Cable Shill
wrote:

Another simple way - the old Native American waiting for a train
method. Push the fish tape all the way until it stops. Person 1 keeps
ramming the fish tape and person 2 puts ear to ground near far end and
listens for it. Needs no batteries or smoke.

Nix the water. I like the compressed air trick, Just don't look
directly at the conduit end . .

Well, how about combining the two methods? Find some flex lawn drip
irrigation tubing. Attach a bosons whistle to the end and shove it
through the pipe. Add compressed air and it should scream like a
banshee. That should be easy to hear through the sand. Maybe the
duct tape will act as a diaphragm.


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

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.)

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

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.

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

"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