Re: [time-nuts] Ultra low phase noise floor measurement system for RF devices.
In a message dated 3/31/2007 18:14:01 Pacific Daylight Time,
bruce.griffiths@xtra.co.nz writes:
Since the average person in the rest of the world copes with the metric
system without any difficulty, the first reason would appear to be based
on a tacit assumption that average US citizen is less intelligent/less
well educated than the average citizen of every other country.
Hi Bruce,
don't think it's related to intelligence, it's got more to do with
dis-interest in my opinion. Once I tried to get a piece of metal cut here in the US
(at a time I was not that familiar with fractions of inches) and gave my
measurements in mm to the shop foreman. He looked at me in disbelief, he had never
worked with SI units.
So then I had to learn about 'standard' measurements such as 3/16" etc -
which I think are just so much more difficult to deal with...
They tried to bring the SI system here in the 70's and failed. Canada
converted successfully.
In my opinion, there is only one single application where SI units don't
work as well: that is in altitude assignments for aircraft, which are in feet in
the western world.
That way the controllers get to stack aircraft in 100/500/1000 feet
increments, which lend themselves more easily to communication and relative altitudes
(aircraft to aircraft separation) due to their ca. 3:1 "improvement" in
resolution over the meter... on another note it's also nice that a foot is about
a ns delay in Lightspeed.
bye,
Said
************************************** See what's free at http://www.aol.com.
The other reason the machinists aren't thrilled with SI units is that
thousandths of an inch are actually a pretty good match for the precision
they usually deal with. In SI, you'd have to deal with micrometers
(microns?), which is too much resolution for most applications, or
millimeters, which is nowhere near enough.
-- john, KE5FX
In my opinion, there is only one single application where SI units don't
work as well: that is in altitude assignments for aircraft, which
are in feet in
the western world.
In France, and I suspect in the rest of the world, machinists talk in
1/100th of a mm (centieme in French). The 'centieme' is a very good
fractional unit when dealing with hardware. It is not harder to talk in
1/100th of a mm than in 1/1000th of an inch. The micrometre (micron in
French, as you correctly stated) is seldom used outside of metrology
labs, optics and specialized applications.
After 33 years in France, and 22 here in the US, I must say I have not
completely converted, by a long shot. The Imperial system is just too
ridiculous. It is an offense to common sense. BTU/hr? please spare me :-)
The Brit's in their belated wisdom (they invented the Imperial system
after all) decided to keep the old units for beer (pint) and do away
with the rest. That's fine with me!
Interesting related event: the local grocery store has a ham cutting
machine that has a dial calibrated in mm. This is apparently not
uncommon in this country, these machines are probably imported. The
other day, as I was buying ham, a new employee asked me how thick, so,
of course, I said 1.5 mm. You should have seen the look on his face, he
had no idea what I was talking about. So I told him it was lingo for
putting the dial between 1 and 2, so he just turned the dial and did not
ask any question...
Didier KO4BB
John Miles wrote:
The other reason the machinists aren't thrilled with SI units is that
thousandths of an inch are actually a pretty good match for the precision
they usually deal with. In SI, you'd have to deal with micrometers
(microns?), which is too much resolution for most applications, or
millimeters, which is nowhere near enough.
-- john, KE5FX
Didier Juges wrote:
In France, and I suspect in the rest of the world, machinists talk in
1/100th of a mm (centieme in French). The 'centieme' is a very good
fractional unit when dealing with hardware. It is not harder to talk in
1/100th of a mm than in 1/1000th of an inch.
Talking isn't the problem, actually machining to 1/100th of a mm is the problem.
Machinists, and the machines they use, run out of steam around a thousandth of
an inch. 1/100th of a mm is a practical impossibility for a lathe, or milling
machine to achieve. But 1/10th of a mm is too course for operations involving
fit (bearings, press fits, ...). So you end up counting in 4/100ths of a mm,
rather than 1/1000ths of an inch.
Cutting threads is a real nightmare with non CNC metric lathes, but super
easy with non CNC English lathes.
After 33 years in France, and 22 here in the US, I must say I have not
completely converted, by a long shot. The Imperial system is just too
ridiculous. It is an offense to common sense. BTU/hr? please spare me :-)
I'm puzzled about why that particular arbitrary constant bothers you.
A BTU is the amount of energy necessary to raise 1 cubic foot of water 1F in
temperature. A BTU/hour takes one hour to raise the temperature of the water.
It is no more, or less, arbitrary than the calorie, but it is a whole lot less
wierd than a calorie/hour, or a kilometer/hour for that matter.
Life will always be a blended system, unless you decide you want a metric day,
metric week, metric year... I don't think that nature will accommodate you very
well.
-Chuck Harris
In message 460FC34F.8070009@erols.com, Chuck Harris writes:
It is no more, or less, arbitrary than the calorie, but it is a whole lot less
wierd than a calorie/hour, or a kilometer/hour for that matter.
You're right, BTU/h is just as arbitrary as the calorie, which is why
the correct SI unit for energy is Joule, which the same as Watt*seconds.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
From: "Poul-Henning Kamp" phk@phk.freebsd.dk
Subject: Re: [time-nuts] Ultra low phase noise floor measurement system forRF devices.
Date: Sun, 01 Apr 2007 14:50:28 +0000
Message-ID: 54520.1175439028@critter.freebsd.dk
In message 460FC34F.8070009@erols.com, Chuck Harris writes:
It is no more, or less, arbitrary than the calorie, but it is a whole lot less
wierd than a calorie/hour, or a kilometer/hour for that matter.
You're right, BTU/h is just as arbitrary as the calorie, which is why
the correct SI unit for energy is Joule, which the same as Watt*seconds.
It takes 4,18 kJ to raise one Litre of water one degree Kelvin.
Everybody knows that, no?
Cheers,
Magnus
Poul-Henning Kamp wrote:
In message 460FC34F.8070009@erols.com, Chuck Harris writes:
It is no more, or less, arbitrary than the calorie, but it is a whole lot less
wierd than a calorie/hour, or a kilometer/hour for that matter.
You're right, BTU/h is just as arbitrary as the calorie, which is why
the correct SI unit for energy is Joule, which the same as Watt*seconds.
We can play that game Poul-Henning, by using joules, one thing becomes easy,
and another becomes hard, but in the end, you always have to return to remembering
arbitrary constants.
How many joules does it take to heat up one gram of water 1C ?
With calories it is easy: 1 calorie.
How many joules does it take to heat up one pound of water 1F ?
With BTU it is easy: 1 BTU.
Metric vs. English has nothing to do with making things easier, but
rather has everything to do with which arbitrary constants you prefer.
-Chuck Harris
In message 460FD021.9000401@erols.com, Chuck Harris writes:
We can play that game Poul-Henning, by using joules, one thing becomes easy,
and another becomes hard, but in the end, you always have to return to remembering
arbitrary constants.
That's likely to be a matter of fact for any universe :-)
How many joules does it take to heat up one gram of water 1C ?
With calories it is easy: 1 calorie.
Right, so it's easy for water, but what about gasoline ?
I far prefer to be able to convert effortlessly between units, than to
embedd arbitrary material properties in my measurement units.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
On Sunday 01 April 2007 11:30, Chuck Harris wrote:
Metric vs. English has nothing to do with making things easier, but
rather has everything to do with which arbitrary constants you prefer.
Here is a question that has nagged me for years, but first
the background:
When I was in school getting my degree, I had a Physics
teacher that gave all of his lectures in the Metric System.
The book covered nothing but the Metric System.
All of the tests he gave where in the English system!
Conversions where never mentioned, anyplace.
Everyone failed the first test.
[This kind of #)$#$ in schools,
is the kind of thing that makes be believe
in Home Schooling.]
The one good thing to come out of that (?), is everyone in class learned
to paying attention to the 'Units'.
In the English System the unit of Weight is the Pound.
The unit of Mass is the Slug.
In the Metric System the unit of Weight is the Newton.
The unit of Mass is the (Kilo)Gram.
So why does this box of cereal (first thing at hand with label)
say "10 Oz (284g)". All of these dual unit labels
are comparing weight vs mass. Why?
I'm sure virtually all Americans think the Gram is a
unit of weight.
--
http://www.softwaresafety.net/ http://www.designer-iii.com/
http://www.unusualresearch.com/
At 02:04 PM 4/1/2007, Bob Paddock wrote:
[This kind of #)$#$ in schools,
is the kind of thing that makes be believe
in Home Schooling.]
Yet another reason I am pleased to be home-schooling my daughter!
John
Poul-Henning Kamp wrote:
In message 460FD021.9000401@erols.com, Chuck Harris writes:
We can play that game Poul-Henning, by using joules, one thing becomes easy,
and another becomes hard, but in the end, you always have to return to remembering
arbitrary constants.
That's likely to be a matter of fact for any universe :-)
How many joules does it take to heat up one gram of water 1C ?
With calories it is easy: 1 calorie.
Right, so it's easy for water, but what about gasoline ?
Somehow, someway, it all comes down to the same thing. Celsius
was designed around the freezing and boiling points of water. One
should expect that other things like calories, which are also defined
around water, should be easier.... gasoline will require you to know
a constant.
I far prefer to be able to convert effortlessly between units, than to
embedd arbitrary material properties in my measurement units.
It would have been just as easy to achieve this simplicity with a metric
system based on pounds, inches and seconds... It wouldn't have been French,
but it would have been just as easy.
-Chuck Harris
From: Bob Paddock bob.paddock@gmail.com
Subject: Re: [time-nuts] Ultra_low_phase_noise_floor_measurement_system forRF_devices.
Date: Sun, 1 Apr 2007 14:04:52 -0400
Message-ID: 200704011404.53053.bob.paddock@gmail.com
On Sunday 01 April 2007 11:30, Chuck Harris wrote:
Metric vs. English has nothing to do with making things easier, but
rather has everything to do with which arbitrary constants you prefer.
Here is a question that has nagged me for years, but first
the background:
When I was in school getting my degree, I had a Physics
teacher that gave all of his lectures in the Metric System.
The book covered nothing but the Metric System.
All of the tests he gave where in the English system!
Conversions where never mentioned, anyplace.
Everyone failed the first test.
[This kind of #)$#$ in schools,
is the kind of thing that makes be believe
in Home Schooling.]
The one good thing to come out of that (?), is everyone in class learned
to paying attention to the 'Units'.
In the English System the unit of Weight is the Pound.
The unit of Mass is the Slug.
In the Metric System the unit of Weight is the Newton.
The unit of Mass is the (Kilo)Gram.
So why does this box of cereal (first thing at hand with label)
say "10 Oz (284g)". All of these dual unit labels
are comparing weight vs mass. Why?
Because there is still 4 states (as in USA) which does not allow metric only
labeling, however work is ongoing. The 2009 cut off in EC is actually pushing
things and many US food manufacteurs is actually pushing for metric only
labeling. FDA is active in the area.
As for your real question: It is tradition really.
I'm sure virtually all Americans think the Gram is a
unit of weight.
Unfortunatly this fine point is being missed by many.
Cheers,
Magnus
Bob Paddock wrote:
On Sunday 01 April 2007 11:30, Chuck Harris wrote:
Metric vs. English has nothing to do with making things easier, but
rather has everything to do with which arbitrary constants you prefer.
Here is a question that has nagged me for years, but first
the background:
When I was in school getting my degree, I had a Physics
teacher that gave all of his lectures in the Metric System.
The book covered nothing but the Metric System.
All of the tests he gave where in the English system!
A standard trick. They want you to learn the algebra of conversions.
The biggest problem I had is I was taking courses in Physics,
Engineering, and Astronomy at the same time. It was a whole lot
of fun switching between mks, cgs, English, and astronomical units
in the same day.
Conversions where never mentioned, anyplace.
Everyone failed the first test.
[This kind of #)$#$ in schools,
is the kind of thing that makes be believe
in Home Schooling.]
The one good thing to come out of that (?), is everyone in class learned
to paying attention to the 'Units'.
In the English System the unit of Weight is the Pound.
The unit of Mass is the Slug.
In the Metric System the unit of Weight is the Newton.
The unit of Mass is the (Kilo)Gram.
So why does this box of cereal (first thing at hand with label)
say "10 Oz (284g)". All of these dual unit labels
are comparing weight vs mass. Why?
Because the folks that write the laws are barely up to the
task. They have no educational basis for understanding that
mass and weight are not the same thing.... because standing flat
footed on Earth, they are.
I'm sure virtually all Americans think the Gram is a
unit of weight.
I doubt that, but for all intents and purposes here on Earth,
a gram is a unit of weight.
Of course, it begs the question of why 1 Newton != 1Kg.
(1Newton = 0.1020Kg at Earth gravity)
-Chuck Harris
I love metric...
A piezes is 10E3 Newtons/sq meter
A piezes is also 1 sthenes/sq meter
A poises is 10E-1 newton-seconds/sq meter
A steres is 1 cubic meter
A stokes is 10E-4 sq meters/second
It's only simple if you stay out of the margins.
From: Chuck Harris cfharris@erols.com
Subject: Re: [time-nuts] Ultra low phase noise floor measurement system forRF devices.
Date: Sun, 01 Apr 2007 14:14:02 -0400
Message-ID: 460FF66A.1070409@erols.com
Poul-Henning Kamp wrote:
In message 460FD021.9000401@erols.com, Chuck Harris writes:
We can play that game Poul-Henning, by using joules, one thing becomes easy,
and another becomes hard, but in the end, you always have to return to remembering
arbitrary constants.
That's likely to be a matter of fact for any universe :-)
How many joules does it take to heat up one gram of water 1C ?
With calories it is easy: 1 calorie.
Right, so it's easy for water, but what about gasoline ?
Somehow, someway, it all comes down to the same thing. Celsius
was designed around the freezing and boiling points of water. One
should expect that other things like calories, which are also defined
around water, should be easier.... gasoline will require you to know
a constant.
But Anders Celsius got it a bit wrong in 1741 there in the beginning, putting
0 degrees to the boiling point and 100 degrees to the melting point of ice.
Fortunatly that misstake was corrected sometime after his death in 1744. :)
Some rumours say it was actually Linné (another Uppsala gigant) that corrected
it, but it cannot be prooven.
I far prefer to be able to convert effortlessly between units, than to
embedd arbitrary material properties in my measurement units.
It would have been just as easy to achieve this simplicity with a metric
system based on pounds, inches and seconds... It wouldn't have been French,
but it would have been just as easy.
We would be running of the royal french inch, some 27,07 mm. :)
Cheers,
Magnus