Ground Penetrating Radar...

[Don Y]

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc. I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!). Did I miss some potential, practical use?

 

[Jan Panteltje]

On a sunny day (Tue, 19 Apr 2022 18:19:09 -0700) it happened Don Y
<blockedofcourse@foo.invalid> wrote in <t3nn2q$mub$1@dont-email.me>:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc. I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!). Did I miss some potential, practical use?

Down under it is used to locate gold veins

 

[Clive Arthur]

On 20/04/2022 02:19, Don Y wrote:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc.  I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!).  Did I miss some potential, practical use?

I used to work for a geophysics company which occasionally used a hired
GPR, usually for detecting buried services on a potential building site.

The resulting reports were so vague and non-committal it was hard to see
what value they had. My overall impression was that GPR probably works
well in a limited set of ground conditions which only exist elsewhere.

This was about 40 years ago though.

--
Cheers
Clive

 

[Mike Coon]

In article <t3nn2q$mub$1@dont-email.me>, blockedofcourse@foo.invalid
says...

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc. I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!). Did I miss some potential, practical use?

Corpse or ghost-hunting?

 

[server]

On Tue, 19 Apr 2022 18:19:09 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc. I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!). Did I miss some potential, practical use?

I supplied the impulse generators for a wideband GPR that was to be
used to de-mine Viet Nam or somewhere. It wasn\'t successful. Rocks,
roots, lumps of junk confused the images.

You can trace wires from their E or H fields. There\'s cheap stuff to
do that.



--

I yam what I yam - Popeye

 

[Don Y]

On 4/20/2022 1:29 AM, Clive Arthur wrote:

On 20/04/2022 02:19, Don Y wrote:
I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc. I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!). Did I miss some potential, practical use?

I used to work for a geophysics company which occasionally used a hired GPR,
usually for detecting buried services on a potential building site.

The resulting reports were so vague and non-committal it was hard to see what
value they had. My overall impression was that GPR probably works well in a
limited set of ground conditions which only exist elsewhere.

Could they not deduce (from GPR results) where the services went based on
knowledge of where they *entered* the property? I.e., use the GPR and some
deductive interpretation to suss out *this* is the path it takes?

> This was about 40 years ago though.

Here, you\'d be foolish to do your own \"survey\" as YOU would be liable for
any damages to those services that were the result of your survey errors.
(periodically, some idiot takes out a back hoe and rips up a gas line
or electric service that he didn\'t know was \"there\")

We have a (free) service that comes out and marks all of the below grade
services (phone, CATV, gas, water, sewer, electric). If you rely on THEIR
markings and end up damaging a service, *they* bear the responsibility.

[Of course, they are often lazy/underpaid and make mistakes. On one
occasion, I had to *correct* the guy marking the gas line as he sort of
\"improvised\" marking the last few ~20 feet. Having *seen* (with my own eyes)
the gas line \"exposed\" when it was installed, I was 100.0% certain in my
recollection of its routing. Guy copped an attitude that *I* was more
knowledgeable than he was. But, knew better than to leave his marks
(liability!) in place without rechecking them.... ooops! \"You\'re welcome!\"]

I\'ve no idea who was using these -- nor how. But, there were several units
available for purchase so I have to assume they were used, regularly.

But, as I couldn\'t come up with an \"excuse\" (as SWMBO would say) to own one,
I had to discipline myself to take a pass on the opportunity. (they are
large enough to be \"noticeable\" and consume a fair bit of storage space -- esp
as you can\'t just put them UP on a shelf!)

<shrug> Some *other* toy will come along to tickle my fancy... :>

 

[Don Y]

On 4/20/2022 1:36 AM, Mike Coon wrote:

In article <t3nn2q$mub$1@dont-email.me>, blockedofcourse@foo.invalid
says...

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc. I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!). Did I miss some potential, practical use?

Corpse or ghost-hunting?

I think it would have use in finding buried (clay) sewer lines -- if
only for the density changes in the soil as they excavated the
trench to lay the pipe. Sort of like sensing a burial site for
similar changes in density.

Most of our \"wired\" utilities were laid in a common trench (at different
Z levels) so those are relatively easy to deduce (you know where the
services enter your property and you know where they connect to the house)

I think they may have used something similar when surveying the O\'odham
site, nearby (think: pit houses)

Maybe if I was \"into\" archeology? <shrug>

I know they use ULF technology to do wider-area ground surveys, but they
are looking for \"bigger\" things.

 

[Ralph Mowery]

In article <t3p4pe$llk$1@dont-email.me>, blockedofcourse@foo.invalid
says...

We have a (free) service that comes out and marks all of the below grade
services (phone, CATV, gas, water, sewer, electric). If you rely on THEIR
markings and end up damaging a service, *they* bear the responsibility.

I have used the service several times. The did not mark the cable TV
one time and it was cut by construction. No come back to me for the
repair.

 

[Don Y]

On 4/20/2022 8:53 AM, Ralph Mowery wrote:

In article <t3p4pe$llk$1@dont-email.me>, blockedofcourse@foo.invalid
says...

We have a (free) service that comes out and marks all of the below grade
services (phone, CATV, gas, water, sewer, electric). If you rely on THEIR
markings and end up damaging a service, *they* bear the responsibility.

I have used the service several times. The did not mark the cable TV
one time and it was cut by construction. No come back to me for the
repair.

Here, the service is really just a sort of \"notification bureau\". They
appear to dispatch the request to each of the separate utilities and
each of *them* decides how to address it.

E.g., the municipal water department sends out a guy to mark the
water main; the phone company sends out a guy to mark the phone line;
the electric company sends out a guy to mark the power; etc.

Several of these \"hire out\" that activity to a third party \"skilled\"
in that activity. Often, *one* person from such a company will come out
and mark multiple services -- no doubt because they are under contract
to those multiple services (and are likely smart enough to know that
a request from service A at address X will likely see a request from
service B at that same address within days/hours -- why dispatch a guy
twice if you can combine the trips?)

It behooves you to learn the various marking colors so you can assure
yourself that they\'ve ALL been marked before starting any work
excavating (regardless of who foots the bill for a f*ckup, YOU will be
the party that is without phone/CATV/electric/gas/etc. if someone
screws up!)

[It\'s annoying that they don\'t use less durable marking materials.
The marks are only \"guaranteed\" for 2 weeks so why make marks that
last YEARS?]

 

[John Walliker]

On Wednesday, 20 April 2022 at 20:35:17 UTC+1, Don Y wrote:

On 4/20/2022 8:53 AM, Ralph Mowery wrote:
In article <t3p4pe$llk$1...@dont-email.me>, blocked...@foo.invalid
says...

We have a (free) service that comes out and marks all of the below grade
services (phone, CATV, gas, water, sewer, electric). If you rely on THEIR
markings and end up damaging a service, *they* bear the responsibility.

I have used the service several times. The did not mark the cable TV
one time and it was cut by construction. No come back to me for the
repair.
Here, the service is really just a sort of \"notification bureau\". They
appear to dispatch the request to each of the separate utilities and
each of *them* decides how to address it.

E.g., the municipal water department sends out a guy to mark the
water main; the phone company sends out a guy to mark the phone line;
the electric company sends out a guy to mark the power; etc.

Several of these \"hire out\" that activity to a third party \"skilled\"
in that activity. Often, *one* person from such a company will come out
and mark multiple services -- no doubt because they are under contract
to those multiple services (and are likely smart enough to know that
a request from service A at address X will likely see a request from
service B at that same address within days/hours -- why dispatch a guy
twice if you can combine the trips?)

It behooves you to learn the various marking colors so you can assure
yourself that they\'ve ALL been marked before starting any work
excavating (regardless of who foots the bill for a f*ckup, YOU will be
the party that is without phone/CATV/electric/gas/etc. if someone
screws up!)

[It\'s annoying that they don\'t use less durable marking materials.
The marks are only \"guaranteed\" for 2 weeks so why make marks that
last YEARS?]

Many years ago a new development was about to be constructed next to a
busy railway station and signal box. A buried cable was found. The power
company insisted that it wasn\'t theirs. The railway company insisted it
wasn\'t theirs. It couldn\'t be because it was not on their land... So the
cable was cut. There was a major signalling failure.
It was many hours before anyone realised the connection between the
two events and restored train services.

John

 

[bitrex]

On 4/20/2022 10:13 AM, jlarkin@highlandsniptechnology.com wrote:

On Tue, 19 Apr 2022 18:19:09 -0700, Don Y
blockedofcourse@foo.invalid> wrote:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc. I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!). Did I miss some potential, practical use?

I supplied the impulse generators for a wideband GPR that was to be
used to de-mine Viet Nam or somewhere. It wasn\'t successful. Rocks,
roots, lumps of junk confused the images.

You can trace wires from their E or H fields. There\'s cheap stuff to
do that.

The magnetometer in your cell phone should be good enough for tracing
wires in walls

 

[Clifford Heath]

On 20/4/22 11:19 am, Don Y wrote:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc.  I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!).  Did I miss some potential, practical use?

My son\'s company uses GPR in a suite of other tools for finding
reinforcing steel inside corroding concrete structures. Their business
is remediating structures (wharves, bridges, tall buildings, mine
hoppers, etc) that would otherwise have to be torn down.

I can\'t vouch for how useful the GPR is compared to other methods.

CH

 

[Don Y]

On 4/20/2022 1:49 PM, John Walliker wrote:

Many years ago a new development was about to be constructed next to a
busy railway station and signal box. A buried cable was found. The power
company insisted that it wasn\'t theirs. The railway company insisted it
wasn\'t theirs. It couldn\'t be because it was not on their land... So the
cable was cut. There was a major signalling failure.
It was many hours before anyone realised the connection between the
two events and restored train services.

You would (naively) *think* that there were records of all of these
pipes, cables, etc. Of course, there are only *general* documents
but lots of missing \"detail\".

When I was a kid, they built a new school in my neighborhood. So, I
spent a lot of time watching all phases of its construction.

Some years later, a crew came along to dig up the roadway (essentially,
the \"driveway\" to the school). I told the back hoe operator to be
careful of the *pipe* buried where he was digging (having SEEN it
being laid there a few years earlier).

\"Go away, kid\" (no record of the pipe on HIS paperwork).

When he *tore* it out of the ground, we ended up with a week\'s
unscheduled vacation as the school was shutdown for its repair!

THIS neighborhood is considerably newer. Yet, they don\'t have accurate
\"maps\" of the buried power lines that daisy-chain each of the transformers
together. And, that\'s just *two* connections (A & C) per group of 4 homes!

 

[Arie de Muijnck]

On 2022-04-21 01:13, bitrex wrote:

On 4/20/2022 10:13 AM, jlarkin@highlandsniptechnology.com wrote:
On Tue, 19 Apr 2022 18:19:09 -0700, Don Y
blockedofcourse@foo.invalid> wrote:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc.  I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!).  Did I miss some potential, practical use?

I supplied the impulse generators for a wideband GPR that was to be
used to de-mine Viet Nam or somewhere. It wasn\'t successful. Rocks,
roots, lumps of junk confused the images.

You can trace wires from their E or H fields. There\'s cheap stuff to
do that.


The magnetometer in your cell phone should be good enough for tracing wires in walls

How would that work, with a DC responding magnetometer reading, and AC through the copper (or Alu) wires? Or are they laid in iron pipes?
Even with an AC responding magnetometer the radiating field from two closely laid wires is very low.

In modern homes here (NL), wires are in plastic pipes. I normally pick up the E field with a simple detector, works even in dry concrete walls.
It fails on 3-phase wiring, the total E field intensity is very low.

Arie

 

[wmartin]

On 4/20/22 16:15, Clifford Heath wrote:

On 20/4/22 11:19 am, Don Y wrote:
I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities,
pipes, etc.  I thought it might have some use on the rooftop (!)
locating wire runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already
have too many \"toys\"!).  Did I miss some potential, practical use?

My son\'s company uses GPR in a suite of other tools for finding
reinforcing steel inside corroding concrete structures. Their business
is remediating structures (wharves, bridges, tall buildings, mine
hoppers, etc) that would otherwise have to be torn down.

I can\'t vouch for how useful the GPR is compared to other methods.

CH

They make great props for many cable TV \"reality\" shows, re hunting
treasure, etc. Lots of minutes burned showing somebody walking around in
a field

 

[Mike Monett]

jlarkin@highlandsniptechnology.com wrote:

On Tue, 19 Apr 2022 18:19:09 -0700, Don Y
blockedofcourse@foo.invalid> wrote:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities, pipes,
etc. I thought it might have some use on the rooftop (!) locating wire
runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already have
too many \"toys\"!). Did I miss some potential, practical use?

I supplied the impulse generators for a wideband GPR that was to be
used to de-mine Viet Nam or somewhere. It wasn\'t successful. Rocks,
roots, lumps of junk confused the images.

You can trace wires from their E or H fields. There\'s cheap stuff to
do that.

Double-D coils can detect various metals by their reflectance and the phase
shift of their response. Here\'s a rough overview:

https://www.metaldetectingworld.com/double_d_search_coils.shtml



--
MRM

 

[server]

On Sun, 24 Apr 2022 07:03:33 -0000 (UTC), Mike Monett <spamme@not.com>
wrote:

jlarkin@highlandsniptechnology.com wrote:

On Tue, 19 Apr 2022 18:19:09 -0700, Don Y
blockedofcourse@foo.invalid> wrote:

I had an opportunity to pick up some of this kit, cheap.
But, couldn\'t come up with a *use* for it!

\"Domestically\", it has limited use locating buried utilities, pipes,
etc. I thought it might have some use on the rooftop (!) locating wire
runs in the closed roof-space (with house unoccupied).

And, I just can\'t imagine a commercial use with which *I* would be
affiliated that could benefit.

So, I \"passed\" on yet-another-toy (SWMBO complains that I already have
too many \"toys\"!). Did I miss some potential, practical use?

I supplied the impulse generators for a wideband GPR that was to be
used to de-mine Viet Nam or somewhere. It wasn\'t successful. Rocks,
roots, lumps of junk confused the images.

You can trace wires from their E or H fields. There\'s cheap stuff to
do that.

Double-D coils can detect various metals by their reflectance and the phase
shift of their response. Here\'s a rough overview:

https://www.metaldetectingworld.com/double_d_search_coils.shtml

I knew some metal detector freaks once. We experimented with various
coil configs. A single coil oscillator, audio heterodyned, was about
best. Human ears are very frequency sensitive and the FM effect is
very intuitive when you\'re waving a coil around.





--

I yam what I yam - Popeye