My wife bought me this package of five or so yellow laser devices. They
throw lines that work okay if you are working in the dark, and the work
doesn't have to be straight or plumb or level.

Then, there's one that measures distance. It doesn't work very well in the
sunlight here in the desert southwest. But, I was playing with it today (a
cloudy day here), and just wondered ..........

How accurate are they? It would be handy for some things I do, or are they
just for guesstimating?

Steve

How accurate are they? It would be handy for some things I do, or are
they
just for guesstimating?

Most of the less expensive laser stuff is advertised as having an accuracy
of 1mm per meter. Some of the cheaper stuff I have seen would be struggling
to even reach that standard. What I do find useful, is using it as a
substitute for a string line, or piano wire. The advantage of a light beam,
is that it's dead nuts straight, and doesn't sag. Just remember to measure
from the edge of the light, not the middle, for best results. Unless you can
calibrate the bubbles, assume any spirit levels are only "moderately"
aligned with the beam of light...

As for the distance measuring device, there should be some indictation
somewhere how accurate it is.

These are mostly trash. I tried one out that someone gave me. It's just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc. It
cost $25,000+ new. It is now obsolete, replaced by GPS.
Bugs

"Bugs" wrote in message
oups.com...
These are mostly trash. I tried one out that someone gave me. It's just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc. It
cost $25,000+ new. It is now obsolete, replaced by GPS.

I'm jealous. My GPS don't do dat. And I have need for sub-centimeter
measurement over long distance. I presume from "obsolete" that you no longer
use it?

Mike.

On Sun, 25 Dec 2005 17:44:04 GMT, "Mike Young"
wrote:

"Bugs" wrote in message
roups.com...
These are mostly trash. I tried one out that someone gave me. It's just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc. It
cost $25,000+ new. It is now obsolete, replaced by GPS.

I'm jealous. My GPS don't do dat. And I have need for sub-centimeter
measurement over long distance. I presume from "obsolete" that you no longer
use it?

Sounds like high-end land surveying gear, probably made just as the
military was first fielding GPS systems. IIRC Surveyors were the
first to buy the equipment and mess around with GPS, and the first to
get the military bypass keys around the "Selective Availability"
encryption.

And they also invented "Differential GPS" - another receiver at a
known fixed datum/bench point transmitting the exact 'fudge factor'
needed to offset the SA accuracy degradation. But you'd still need to
run the plots with the computerized laser transit to verify the
figures and points.

Now that they've given up on SA, they probably allow the high-
accuracy GPS systems to be the final arbiter - right?

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

According the Garmins website about GPS the first satellite was launched in
1978

--

Clif Holland KA5IPF
www.avvid.com


"John" wrote in message
...
"Bruce L. Bergman" wrote:

On Sun, 25 Dec 2005 17:44:04 GMT, "Mike Young"
wrote:

"Bugs" wrote in message
roups.com...
These are mostly trash. I tried one out that someone gave me. It's
just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc.
It
cost $25,000+ new. It is now obsolete, replaced by GPS.

I'm jealous. My GPS don't do dat. And I have need for sub-centimeter
measurement over long distance. I presume from "obsolete" that you no
longer
use it?

Sounds like high-end land surveying gear, probably made just as the
military was first fielding GPS systems. IIRC Surveyors were the
first to buy the equipment and mess around with GPS, and the first to
get the military bypass keys around the "Selective Availability"
encryption.

And they also invented "Differential GPS" - another receiver at a
known fixed datum/bench point transmitting the exact 'fudge factor'
needed to offset the SA accuracy degradation. But you'd still need to
run the plots with the computerized laser transit to verify the
figures and points.

Now that they've given up on SA, they probably allow the high-
accuracy GPS systems to be the final arbiter - right?

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

They had gps in the late 60's. The one thing they didn't have was the
miniature computers to spit out the computations. All the raw data was
taken back to the lab and processed to fine the position information.
It took about six minutes of data to get a reasonable position.

John

"Bruce L. Bergman" wrote:

On Sun, 25 Dec 2005 17:44:04 GMT, "Mike Young"
wrote:

"Bugs" wrote in message
roups.com...
These are mostly trash. I tried one out that someone gave me. It's just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc. It
cost $25,000+ new. It is now obsolete, replaced by GPS.

I'm jealous. My GPS don't do dat. And I have need for sub-centimeter
measurement over long distance. I presume from "obsolete" that you no longer
use it?

Sounds like high-end land surveying gear, probably made just as the
military was first fielding GPS systems. IIRC Surveyors were the
first to buy the equipment and mess around with GPS, and the first to
get the military bypass keys around the "Selective Availability"
encryption.

And they also invented "Differential GPS" - another receiver at a
known fixed datum/bench point transmitting the exact 'fudge factor'
needed to offset the SA accuracy degradation. But you'd still need to
run the plots with the computerized laser transit to verify the
figures and points.

Now that they've given up on SA, they probably allow the high-
accuracy GPS systems to be the final arbiter - right?

-- Bruce --

--
Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700
5737 Kanan Rd. #359, Agoura CA 91301 (818) 889-9545
Spamtrapped address: Remove the python and the invalid, and use a net.

They had gps in the late 60's. The one thing they didn't have was the
miniature computers to spit out the computations. All the raw data was
taken back to the lab and processed to fine the position information.
It took about six minutes of data to get a reasonable position.

John

In article bnIrf.2275$wQ3.290@trnddc05,
says...
According the Garmins website about GPS the first satellite was launched in
1978


Before that it was Loran, but accuracy was nowhere near
what GPS can do, and Loran's resolution is highly dependent
on your location. I was working on boats around the time
GPS was introduced and because of the limited number of
satellites circa 1980 you could only count on getting a GPS
fix something like 2-3 times per hour.

I had friends in offshore lobster fishing, and IIRC they
were still relying primarily on Loran to locate their gear
into at least the early 80s.

Ned Simmons

4. Mike Young
Dec 25, 12:44 pm show options

Newsgroups: rec.crafts.metalworking
From: "Mike Young" - Find messages by this
author
Date: Sun, 25 Dec 2005 17:44:04 GMT
Local: Sun, Dec 25 2005 12:44 pm
Subject: Laser measuring devices
Reply | Reply to Author | Forward | Print | Individual Message | Show
original | Report Abuse


"Bugs" wrote in message


oups.com...


These are mostly trash. I tried one out that someone gave me. It's just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc. It
cost $25,000+ new. It is now obsolete, replaced by GPS.


I'm jealous. My GPS don't do dat. And I have need for sub-centimeter
measurement over long distance. I presume from "obsolete" that you no
longer
use it?

I still get it out once in a while to do some work around the house.
Can't really justify keeping it. It also has a fairly primitive data
collector. It's a Nikon 1 sec. laser theodolite.
Bugs

Ned Simmons wrote:
In article bnIrf.2275$wQ3.290@trnddc05,
says...

According the Garmins website about GPS the first satellite was launched in
1978



Before that it was Loran, but accuracy was nowhere near
what GPS can do, and Loran's resolution is highly dependent
on your location. I was working on boats around the time
GPS was introduced and because of the limited number of
satellites circa 1980 you could only count on getting a GPS
fix something like 2-3 times per hour.

I had friends in offshore lobster fishing, and IIRC they
were still relying primarily on Loran to locate their gear
into at least the early 80s.

Ned Simmons


There were a couple of navigation satellite systems before GPS. One
required visual sighting of a satellite, and tables of the ephemeris- a
real pain to use. I believe it was based on triangulation rather than
the GPS tri-lateration. Wish I could remember the name of it.

GPS was a second generation navsat.

Bugs wrote:
4. Mike Young
Dec 25, 12:44 pm show options

Newsgroups: rec.crafts.metalworking
From: "Mike Young" - Find messages by this
author
Date: Sun, 25 Dec 2005 17:44:04 GMT
Local: Sun, Dec 25 2005 12:44 pm
Subject: Laser measuring devices
Reply | Reply to Author | Forward | Print | Individual Message | Show
original | Report Abuse


"Bugs" wrote in message


oups.com...



These are mostly trash. I tried one out that someone gave me. It's just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc. It
cost $25,000+ new. It is now obsolete, replaced by GPS.



I'm jealous. My GPS don't do dat. And I have need for sub-centimeter
measurement over long distance. I presume from "obsolete" that you no
longer
use it?

I still get it out once in a while to do some work around the house.
Can't really justify keeping it. It also has a fairly primitive data
collector. It's a Nikon 1 sec. laser theodolite.
Bugs


For high precision GPS you need differential GPS. If in the sticks, you
may need to create your own pseudo-satellite, but near populated areas
and major airports, you may be able to use someone else's. I see many
of the consumer GPS systems now say they are capable of differential GPS.

Also, even with differential, to get sub-cm precision you need to sit
receiver there for a lengthy time, averaging the readings.

In article ,
Don Stauffer wrote:

Ned Simmons wrote:
In article bnIrf.2275$wQ3.290@trnddc05,
says...

According the Garmins website about GPS the first satellite was launched in
1978



Before that it was Loran, but accuracy was nowhere near
what GPS can do, and Loran's resolution is highly dependent
on your location. I was working on boats around the time
GPS was introduced and because of the limited number of
satellites circa 1980 you could only count on getting a GPS
fix something like 2-3 times per hour.

I had friends in offshore lobster fishing, and IIRC they
were still relying primarily on Loran to locate their gear
into at least the early 80s.

Ned Simmons


There were a couple of navigation satellite systems before GPS. One
required visual sighting of a satellite, and tables of the ephemeris- a
real pain to use. I believe it was based on triangulation rather than
the GPS tri-lateration. Wish I could remember the name of it.

Transit? Actually, one used the doppler signal from the satellite as it
flew by, in low orbit. It did have to be visible, which was not always
true, but once in view the receiver did the work.


Joe Gwinn

On 26 Dec 2005 05:09:31 -0800, "Bugs" wrote:

4. Mike Young
Dec 25, 12:44 pm show options

Newsgroups: rec.crafts.metalworking
From: "Mike Young" - Find messages by this
author
Date: Sun, 25 Dec 2005 17:44:04 GMT
Local: Sun, Dec 25 2005 12:44 pm
Subject: Laser measuring devices
Reply | Reply to Author | Forward | Print | Individual Message | Show
original | Report Abuse


"Bugs" wrote in message


roups.com...


These are mostly trash. I tried one out that someone gave me. It's just
about useless.
I do have a laser instrument that will read distances up to 3 mi. to
+/- 1 mm and reads angles, vertical & horizontal to 1 second of arc. It
cost $25,000+ new. It is now obsolete, replaced by GPS.


I'm jealous. My GPS don't do dat. And I have need for sub-centimeter
measurement over long distance. I presume from "obsolete" that you no
longer
use it?

I still get it out once in a while to do some work around the house.
Can't really justify keeping it. It also has a fairly primitive data
collector. It's a Nikon 1 sec. laser theodolite.
Bugs

If you cant find the room for it..Im sure Id put it to good use, when
accompanied by a 300 Winchester Magnum. My little double image range
finder isnt accurate enough out past 600 meters.

And I have some friends with .50 Barretts.....

Gunner

"Pax Americana is a philosophy. Hardly an empire.
Making sure other people play nice and dont kill each other (and us)
off in job lots is hardly empire building, particularly when you give
them self determination under "play nice" rules.

Think of it as having your older brother knock the **** out of you
for torturing the cat." Gunner