Ultrasonic Sensors

[Stanley Barthfarkle]

There are companies that will do the locates for you...

They're called utilities, as in electric power, CATV and telephone
companies. They don't charge for coming out to locate their wires for
you. There's a page in the front of most phone books with the heading,
"Call Before You Dig".


Found a lot of high power cables less than 36" below grade, have you?
Power companies lay their lines deeper than the trencher can reach.

Not only is it illegal to machine trench over or within 3 feet of a locate
mark, it is considered incredibly stupid. There are very few utilities that
are precisely the correct depth. We've found electric svc drops at 12",
phone at 3". CATV and sprinklers are sure to get cut regardless. And you
DON'T want to know what a cut gas or water line will do to a house if you
damage it closeby. Most utilities are the right depth or deeper, but you
really don't want to gamble with that kind of liability. Also, any svc
utilities on one's property were likely put in by the contractor or subs,
and are less likely to be at proper, uniform depth.

Some things are difficult or impossible to locate properly, such as PVC
drain cleanouts, (a common thing in the yards of newer homes) gutter drain
lines, sprinkler pipes, low voltage lighting wire, outbuilding a/c circuits,
etc etc. Takes a trained eye to spot these things reliably, and a liability
policy to ensure that they're fixed properly if damaged.

Even found a 3-phase subdivision feeder coming off a pole, down a riser, and
UG, ostensibly 4' deep, which was located by hand at about 2 INCHES, in PVC
conduit, in a road right-of-way about 30' from the riser, less than 5' from
the first house's property line. The bozos couldn't figure out how to
jackhammer through a boulder, I guess. Could have killed our shovel guy, and
almost certainly would have killed the crew coming in to install the lighted
rock wall and landscaping for the subdivision entrance the next week.

Another horror story- fiberoptic telecom cable. While this is usually found
elsewhere, there ARE places where a right-of-way cuts through or between or
abuts someone's property. This stuff is INCREDIBLY expensive to repair- it
has to be spliced in a "clean-room" environment with a very expensive mobile
setup. Cut a 1000 conductor fiber and you'll soon appreciate just how cheap
professional liability insurance is. I knew of a contractor that did this in
the late 80's, and they were fighting with the ins. co to determine the
liability for a very long time.

Anyway, point is it isn't wise to tell folks to "go for it" until providing
full, appopriate info and professional guidance. Even then, they should be
aware that there ARE risks, both physical and financial. This is NOT like
running a door sensor wire and hitting a 110V A/C circuit...

 

[Robert L Bass]

They call it Blue Stake out here and the

service is free...they mark everything in
purty colors...gas/electric/telcom/etc.

Exactly. Also, as long as you call first and don't dig between their marked
boundaries you have zero liability if you hit something.

As to SB's comments, there's no high tension cable within the typical 18"
depth he would use for low voltage signal cables. Stanley Barfbuckle's
nonsense story of rocks flying out of ditches and drivers leaping off
tractors is not only pur fiction. It's irrelevant. We're talking about
little walk-behind units and he's talking about a tractor you'd drive on.
Next thing you know FO will brag of jumping off an inverted 3500 because it
levitated into an open-front, high voltage cabinet.

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233
941-866-1100 Sales & Tech Support
http://www.bassburglaralarms.com
=============================>

 

[Robert L Bass]

Not only is it illegal to machine trench over or

within 3 feet of a locate mark, it is considered
incredibly stupid...

You're the one who boasted that your company did so.

We've found electric svc drops at 12"....

Uh-huh, sure.

... Also, any svc utilities on one's property...
--- snip stuff intended to scare DIYer into hiring a pro ---

Takes a trained eye to spot these things reliably...

Like the one your guy was looking through when he hit the high tension line?
You can't have it both ways, Barfbuckle. Either this stuff is easier than
you claim it is or you and your coworkers are incompetent clods. Either way
the client is better off DIY.

Anyway, point is it isn't wise to tell folks
to "go for it"...

It's wiser than telling everyone to "hire a pro" to do simple low voltage
work just because that's how you make your living.

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233
941-866-1100 Sales & Tech Support
http://www.bassburglaralarms.com
=============================>

 

[Stanley Barthfarkle]

They call it Blue Stake out here and the

Exactly. Also, as long as you call first and don't dig between their
marked boundaries you have zero liability if you hit something.

As to SB's comments, there's no high tension cable within the typical 18"
depth he would use for low voltage signal cables. Stanley Barfbuckle's
nonsense story of rocks flying out of ditches and drivers leaping off
tractors is not only pur fiction. It's irrelevant. We're talking about
little walk-behind units and he's talking about a tractor you'd drive on.
Next thing you know FO will brag of jumping off an inverted 3500 because
it levitated into an open-front, high voltage cabinet.

Are you willing to put the statement "there's no high tension cable within
the typical 18" depth he would use for low voltage signal cables." in
writing, signed and notarized? If so, send it to the guy who sounds like he
doesn't know a/c from dc and tell him to trench away...

PS- There are no "high-tension" wires UG. You moron. Those are the 18,000 V
wires you see from large metal towers hanging from 4' insulators. You moron.
Can't bury those UG. You moron.

Not only is my story 100% verifiable, since there were at least 8 people
present, but there are many instances of electrical "explosions" throwing
rocks, dirt, and other debris when a 3-phase is suddenly sent to ground.
You're trying to argue with facts, Robert.

No, the tractor didn't come off the ground, or even move. The energy sent
rocks out of the trench, along with pieces of what used to be the dig chain.

What you seem to be failing to undertsand is that the little walk-behind
trenchers are much more dangerous to an operator than the riders. Why?
Because your dumb penny-pinching ass is grounded when walking behind one,
regardless of whether you are wearing rubber-soled shoes or not. With a
rider, you at least have the option of jumping clear of the energized
machine. When you are HOLDING ON to the damned thing standing on the ground,
your ass is DONE if you hit a 600 VAC feeder line, and probably even hitting
one or both hot legs of the 220V house drop. Period. End of story. Ever hear
of DEW, you know-it-all fat slob Felon JO MF?

Yet another example of Robert telling someone who KNOWS what they are
talking about that he knows more, even though he has ZERO experience in the
area. Google doesn't make you an expert, Roberta.

A common rental walk-behind unit will trench 3' deep- I know, since I just
rented one last Fall to replace a water service line at one of my rental
properties, which I trenched 36" deep. Yeah, tell him it's a no-brainer so
you can sell him a few items and make a few bucks. I don't have any problem
with selling him equipment and giving him guidance, but telling him not to
worry or consider hiring out the hard stuff is irresponsible. He needs to
know the risks. This is NOT like running a siren in an attic.

 

[Jim]

My need is to monitor the perimeter of an outdoor area.
I am considering ultrasonic sensors to act as an intrusion monitor.
They need to be mounted near ground level.

I need a device similar to what I see on upper-priced automobiles that
indicate the presence of items around its perimeter.
I have seen a very nice system mounted on the bumper of a BMW that
works extremely well to indicate a person walking around the vehicle.

The sensor must be designed for outdoor/external applications.

There will be a series of sensors with patterns that overlap to provide
detection around the entire perimeter.
They will all be wired to a controller that will sound an alarm when
the perimeter has been entered.

Perimeter size can vary from one hundred to several hundred feet.

Since they will be used outdoors, what will the issues be?

Therefore, I am looking for low-power, reliable sensors and the
suggested controller to manage the system.

Of course, price will be a determinig factor.

As you can see from the results of your posting, you are being
"stalked" by an unethical parts pusher by the name of Robert Bass. His
entire existance here is based on telling people lies so that they will
buy parts from him. He will tell anyone who comes here looking for
infromation, that they will find whatever it is they want to do an easy
task. He's an inexperienced book educated parts pusher who work out of
his home or from out of the country. He stocks no parts and simply
makes money by giving people wrong or incomplete information and
selling them parts shipped directly to them from distributors in their
area. He has a long record of unanswered Better Business Bureau
complaints, and is an agitator and argumentative jerk who misleads
people into thinking he actually knows something about present day
alarms sytems.

He has no license to install alarms systems because he's a convicted
felon for threatening a family member with a gun. He's also responsible
for someones death.

As you can see by the responses in this thread he has insulted and
offeded numerous people in this Newsgroup and that he is a pariah in
this group. It is strongly recommended that you avoid corresponding
with him and doing business with him.

 

[Robert L Bass]

Are you willing to put the statement "there's

no high tension cable within the typical 18"
depth he would use for low voltage signal
cables." in writing, signed and notarized?
If so, send it to the guy who sounds like he doesn't know a/c from dc and
tell him to
trench away...

Were you born this stupid or did you have to work at it?

Not only is my story 100% verifiable...

Su-u-ure it is. Uh-huh.

since there were at least 8 people present...

Have any of them snap-rolled a 737?

but there are many instances of electrical
"explosions" throwing rocks, dirt, and
other debris when a 3-phase is suddenly
sent to ground.

I didn't say that if your fictitious story had been true there would not
have been an explosion. However, even if it had not been a lie it would not
have thrown rocks 75 feet away.

You're trying to argue with facts, Robert.

That never stopped you.

No, the tractor didn't come off the ground,
or even move...

You obviously didn't catch the reference, either because you never read FO's
ridiculous stories of snap-rolling airliners and levitating ladders or
because you're too dense to see it.

The energy sent rocks out of the
trench, along with pieces of what
used to be the dig chain.

Nope. I've seen what happens when a metal object shorts a high voltage,
underground line. There's a loud bang and a puff of smoke. A few inches of
the metal is typically vaporized, along with some of the cable. There's
nothing like an explosive force that would send rocks and bits of chain
flying 75 feet away. Part of that is due to the amount of energy involved.
Part is due to what happens to the metal device (in your silly story a
cutting chain) which comes into contact with the conductors. It welds in
place and vaporizes. It doesn't burst into pieces since there's nothing
inside it to create explosive gas.

Do you know why trees sometimes explode when lightning strikes them? It's
the water and sap (no, not you; the other kind) inside the wood rapidly
turning to vapor. If the wood was old and dry like houshold lumber it would
simply ignite -- like a house. No moisture inside = no explosion.
Transformers are filled with an oily substance which helps transfer heat
away from the windings. When the secondaries are shorted the oil heats up
so fast it causes an explosion. I saw a 10 or 12 foot tall steel sliding
board at the end of a pier in Ocean Gate, NJ take a direct lightning hit.
Some of the metal was vaporized. Some turned to a cinder. None of it was
sent flying because there was no explosion. The wooden pier beneath the
slide suffered a different type of damage. Several of the wood pilings,
which were water-logged (pun not intended) burst open like firecrackers.

What you seem to be failing to undertsand
is that the little walk-behind trenchers are
much more dangerous to an operator than
the riders...

What you fail to understand (among oh, so many other things) is that the
trenchers don't reach high power lines and that they are grounded better
than the operator.

Why? Because your dumb penny-pinching
ass is grounded when walking behind one...

I don't know about you but I don't drag my behind on the ground. I also
understand (and you clearly don't) that electricity takes the path of least
resistance to ground. My sneakers or work boots offer far better insulation
than the metal trencher which is below grade (ie, grounded).

Let me know if you need help with some of this. It may be a little
complicated for you.

regardless of whether you are wearing
rubber-soled shoes or not. With a rider,
you at least have the option of jumping
clear of the energized machine...

With a rider you (well not you personally; I mean someone who actually has
done this) also have a much greater chance of hitting a high power line due
to the greater depth of the trench it digs.

When you are HOLDING ON to the damned
thing standing on the ground, your ass is DONE
if you hit a 600 VAC feeder line, and probably
even hitting one or both hot legs of the 220V
house drop. Period. End of story...

An electrician friend of mine was asked to install ground lights on the
front lawn of our church several years ago. In the process he did just
that -- hit a high voltage line -- with a post hole digger. There was a
loud bang as the transformer on thepole at the street exploded. There was
also a puff of smoke from the hole. A few inches of the post hole digger
were gone. The electrician? He was fine; didn't even get a tingle.

Ever hear of DEW...

The Distant Early Warning system? Sure, it was installed decades ago but
they probably didn't use trenchers.

you know-it-all fat slob Felon JO MF?

Every time you lose an argument you resort to that sort of chldish gutter
talk.

A common rental walk-behind unit will
trench 3' deep...

The ones I used to use would only go 24' or 30". They didn't have an oblong
chain like the new models. Instead there was a large, rotating disk.
However, if you had actually used one of them (even once) you would know
that the depth is adjustable.

- I know, since I just rented one last Fall...

And yet you survived? See, I told you.

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233
941-866-1100 Sales & Tech Support
http://www.bassburglaralarms.com
=============================>

 

[Robert L Bass]

Not only is it illegal to machine trench over or

We made mistakes...
Clearly.


Google it, Robert. You're a "google expert".

Didn't you say earlier that Google doesn't count or some such drivel?

Trenching is simple. Doing it safely and without
fucking things up is difficult. We made mistakes...

OK, we agree. For you it is difficult. For normal people (ie, those with
the capacity to think and to look at the markers) it's pretty simple stuff.

Yeah- he's better off DIY trenching around his property...

Good. You finally see. I knew there was hope.

Uhuh. You believe this shit, don't you?

About the exploding rocks and flying tractor jockeys? Nope.

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233
941-866-1100 Sales & Tech Support
http://www.bassburglaralarms.com
=============================>

 

[Stanley Barthfarkle]

To anyone still following this thread- Trenching is serious business. It can
be done with proper planning, but significant risks do exist. To deny the
risks is foolish.

Can you? Probably.

Should you? Only you can decide after being presented with all the pertinent
information. Only a fool, or a person with something to gain would say it's
"simple" or "without risk".


I love to save money, but if I didn't have proper experience, I would find a
friend who had some experience and utilize his/her expertise. Make friends
with the guy at the rental place- anything to reduce the risks. Bass would
have you believe that everyone except him is anti-DIY. Not so; DIY is a
great way to save money, IF you are prepared and get all the facts. It's
truly offensive to have someone who has ZERO trenching experience tell us
that there is no physical or financial risk involved with underground
trenching.

 

[Stanley Barthfarkle]

To anyone still following this thread- Trenching is serious business. It can
be done with proper planning, but significant risks do exist. To deny the
risks is foolish.

Can you? Probably.

Should you? Only you can decide after being presented with all the pertinent
information. Only a fool, or a person with something to gain would say it's
"simple" or "without risk".


I love to save money, but if I didn't have proper experience, I would find a
friend who had some experience and utilize his/her expertise. Make friends
with the guy at the rental place- anything to reduce the risks. Bass would
have you believe that everyone except him is anti-DIY. Not so; DIY is a
great way to save money, IF you are prepared and get all the facts. It's
truly offensive to have someone who has ZERO trenching experience tell us
that there is no physical or financial risk involved with underground
trenching.

 

[Robert L Bass]

To anyone still following this thread- Trenching

is serious business...

Do you really think anyone is still following this thread?

It can be done with proper planning, but
significant risks do exist. To deny the risks
is foolish.

The same can be said of driving one's car. However, walk-behind trenchers
are probably safer since they don't approach highway speeds. :^)

Can you? Probably.

Should you? Only you can decide after being
presented with all the pertinent information...

Fortunately, all pertinent information, including risks and operating
instructions, is made available by most reputable rental agencies.
Trenchers are like any other power equipment. You need to exercise proper
care in operating them so you don't get hurt. Since you'll be digging above
power lines and such it's wise to "call before you dig". Contrary to what
one ill-informed individual has said, there's no fee for having someone come
out and mark the area for underground utilities. Low voltage security
cables don't need to be buried as deeply as high voltage cables so the risk
of hitting one with the trencher is minimal if you use common sense.

Only a fool, or a person with something to gain
would say it's "simple" or "without risk"...

On the contrary, it acually is a simple task operating trencher. Life, as a
rule, entails risk.

I love to save money, but if I didn't have proper
experience, I would find a friend who had some
experience and utilize his/her expertise...

DIYers tend to be self-reliant -- ask for advice if you don't understand
something. While I make no effort to hide my financial interest in
encouraging folks to consider DIY, the other gentleman (who hides behind a
fictitious name like most of the people who pollute this newsgroup), doesn't
admit that his real reason for trying to argue against DIY is personal
animus. That shines through in the belligerant, vulgar talk which peppers
his posts.

Make friends with the guy at the rental place...

This can best be accomplished by renting from him. :^)

--

Regards,
Robert L Bass

=============================>
Bass Home Electronics
4883 Fallcrest Circle
Sarasota · Florida · 34233
941-866-1100 Sales & Tech Support
http://www.bassburglaralarms.com
=============================>

 

[Stanley Barthfarkle]

To anyone still following this thread- Trenching is serious business. It can
be done with proper planning, but significant risks do exist. To deny the
risks is foolish.

Can you? Probably.

Should you? Only you can decide after being presented with all the pertinent
information. Only a fool, or a person with something to gain would say it's
"simple" or "without risk".


I love to save money, but if I didn't have proper experience, I would find a
friend who had some experience and utilize his/her expertise. Make friends
with the guy at the rental place- anything to reduce the risks. Bass would
have you believe that everyone except him is anti-DIY. Not so; DIY is a
great way to save money, IF you are prepared and get all the facts. It's
truly offensive to have someone who has ZERO trenching experience tell us
that there is no physical or financial risk involved with underground
trenching.

 

[Rapid]

Exactly. Also, as long as you call first and don't dig between their marked
boundaries you have zero liability if you hit something.

you might DIE but at least according to rlb there is no liability.

As to SB's comments, there's no high tension cable within the typical 18"
depth he would use for low voltage signal cables.

you can insulate yourself with all those boxes of condoms you brag about
carrying around with you on your little "vacations"

Stanley Barfbuckle's

nonsense story of rocks flying out of ditches and drivers leaping off
tractors is not only pur fiction. It's irrelevant. We're talking about
little walk-behind units and he's talking about a tractor you'd drive on.
Next thing you know FO will brag of jumping off an inverted 3500 because it
levitated into an open-front, high voltage cabinet.

was that cabinet stuffed full of paper? from rlb wanting his
EXcustomers to be informed about all that stuff that nobody ever reads
except installers? if so it probably burst into flames and then bASS
cooked some burgers for the tribe.

 

[Tommy]

More information would be helpful on what you are trying to protect.
Just a perimeter, look into photo beams.
watch an area try outdoor motion detectors.

There are many ways to secure an outdoor area, but all have drawbacks
and could possible lead to a higher false alarm rate if not tailored to
your situation. So can you give a little more background on what you
are trying to protect?

Also if you have read the flame session that this thread has become,
you will see RL bass has his hand in it. he runs aon online alarm parts
website. He sometimes gives good advice, but more often than not he
starts these little arguments.

 

[rgondzur]

Whew!
After wading through all the "dialog", it's nice to get back to the
original discussion.
The actual area that I want to monitor is small.
For example, take a stake in the ground, attach a ten-foot rope and
walk a circle around the post. You have a circle with a ten-foot
radius.
Now replace the ten-foot rope with a twelve-foot rope and repeat the
process to create a concentric circle with a twelve-foot radius. The
difference between the two circles, two-foot of radius is the area that
I want to monitor. Anyone walking into the two-feet wide perimeter is
who I want to recognize. Consider it the demilitarized zone around the
inner circle.
In my original posting, I mentioned the parking sensor system on a BMW
auto. It indicates when someone approaches the car and gets within two
or three feet of it. The car is replaced by my inner circle, the area I
want to protect.
The catch is, people are allowed to walk through the outer circle and
into the inner circle. Therefore, the sensors can't hinder their
progress. I just need to know when have approached the inner circle by
passing through the demilitarized zone.
I believe the BMW uses ultrasonic sensors with a moderately focused
beam, but I don't know that for a fact. However they are sensing
objects, it is a fairly solid system with few false alarms.
I originally was thinking of using wireless motes interfacing with the
sensors to form a mesh network, but rethinking the process will allow
for wired sensors. That will help with power consumption of the sensors
themsselves and simplify the controller monitoring the sensors..

One final issue is that it won't always be a nicely-formed circle. They
can have odd shapes, kidney, oblong, ... so there positioning of the
sensors to achieve overlap around the perimeter will vary.

If I can find a reliable sensor like the auto uses, I'll be in
business.

 

[Stanley Barthfarkle]

One final issue is that it won't always be a nicely-formed circle. They
can have odd shapes, kidney, oblong, ... so there positioning of the
sensors to achieve overlap around the perimeter will vary.

If I can find a reliable sensor like the auto uses, I'll be in
business.

It would still help to know <what> you are trying to protect. A building? An
outdoor landscaped area? A pond? Don't know how to respond without knowing
what it is.

 

[rgondzur]

I would be monitoring outdoor landscaped areas. They could contain
ponds, waterfalls, ...
They will vary in size and shape so there is no well-defined perimeter
that is consistent from one installation to the next. The perimeter
will more often than not be finished with stone or concrete rather than
natural grass and soil.

Infra red barriers would be an option if the shape of the perimeter was
symmetrical but it will often not be that way.

Per my previous post, I was thinking of trying ultrasonics mounted at
the perimeter of the inner circle, pointing toward the outer circle. I
would have to space them close enough so their sensing patterns overlap
to guard the entire perimeter.

 

[Stanley Barthfarkle]

I would be monitoring outdoor landscaped areas. They could contain
ponds, waterfalls, ...
They will vary in size and shape so there is no well-defined perimeter
that is consistent from one installation to the next. The perimeter
will more often than not be finished with stone or concrete rather than
natural grass and soil.

Infra red barriers would be an option if the shape of the perimeter was
symmetrical but it will often not be that way.

Per my previous post, I was thinking of trying ultrasonics mounted at
the perimeter of the inner circle, pointing toward the outer circle. I
would have to space them close enough so their sensing patterns overlap
to guard the entire perimeter.

That's going to be a tough one. Never heard of a product that was designed
for what you are trying to do. The automobile backup sensors have never been
used for security purposes that I'm aware of. Once upon a time, ultrasonic
volumetric sensors were used INDOORS for space protection- quite unreliably,
I might add.

The key here is that you're trying to protect a narrow, curving strip of
perimeter area, and don't want any gaps. (in other words, spot protection
won't work) A reliable technology that provides proper catch performance
while eliminating false alarms in an outdoor area is going to be quite a
feat. If someone comes up with a viable, real world solution, and not just
an idea on paper, I'd love to hear about how they did it.

 

[Crash Gordon]

If I were bidding it...I'd walk away. You're asking for headaches.
In addition in case you haven't heard: Forget the ultrasonics already.



|I would be monitoring outdoor landscaped areas. They could contain
| ponds, waterfalls, ...
| They will vary in size and shape so there is no well-defined perimeter
| that is consistent from one installation to the next. The perimeter
| will more often than not be finished with stone or concrete rather than
| natural grass and soil.
|
| Infra red barriers would be an option if the shape of the perimeter was
| symmetrical but it will often not be that way.
|
| Per my previous post, I was thinking of trying ultrasonics mounted at
| the perimeter of the inner circle, pointing toward the outer circle. I
| would have to space them close enough so their sensing patterns overlap
| to guard the entire perimeter.
|

 

[Nomen Nescio]

Stanley Barthfarkle said:

The key here is that you're trying to protect a narrow, curving strip of
perimeter area, and don't want any gaps. (in other words, spot protection
won't work) A reliable technology that provides proper catch performance
while eliminating false alarms in an outdoor area is going to be quite a
feat. If someone comes up with a viable, real world solution, and not just
an idea on paper, I'd love to hear about how they did it.

A buried cable system would work. Two coax cables with intentionally leaky
shields establish a radio field between them. A human body within this
area affects the field, much like a radio's reception can be affected if
you grab onto the antenna. Warning: this stuff isn't even remotely cheap,
and it requires trenching, obviously. I would not consider this a DIY
project.

- badenov

 

[Crash Gordon]

hmmm...maybe some mil spec siesmic detectors cross-zoned with dual beam
pirs? whatever it will be it will be very expensive.


| Stanley Barthfarkle said:
|
| >The key here is that you're trying to protect a narrow, curving strip of
| >perimeter area, and don't want any gaps. (in other words, spot protection
| >won't work) A reliable technology that provides proper catch performance
| >while eliminating false alarms in an outdoor area is going to be quite a
| >feat. If someone comes up with a viable, real world solution, and not
just
| >an idea on paper, I'd love to hear about how they did it.
|
| A buried cable system would work. Two coax cables with intentionally
leaky
| shields establish a radio field between them. A human body within this
| area affects the field, much like a radio's reception can be affected if
| you grab onto the antenna. Warning: this stuff isn't even remotely
cheap,
| and it requires trenching, obviously. I would not consider this a DIY
| project.
|
| - badenov
|
|