Copyright: 1996 - 2024
BSEE - KB3UON
RF Cafe began life in 1996 as "RF Tools" in an AOL screen name web space totaling
2 MB. Its primary purpose was to provide me with ready access to commonly needed
formulas and reference material while performing my work as an RF system and circuit
design engineer. The World Wide Web (Internet) was largely an unknown entity at
the time and bandwidth was a scarce commodity. Dial-up modems blazed along at 14.4 kbps
while typing up your telephone line, and a nice lady's voice announced "You've Got
Mail" when a new message arrived...
All trademarks, copyrights, patents, and other rights of ownership to images
and text used on the RF Cafe website are hereby acknowledged.
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Teaching an Old Dog New Tricks
Teaching an Old Dog New Tricks
"It's hard to teach an
old dog new tricks" - or so goes the adage. I think the actuality is that it's not
teaching an old dog a new trick that is so hard - what is hard is convincing the
dog that the new trick is worth repeating on command. That is an apt analogy for
those of us that were raised on the system of English units, and have been dragged
kicking and screaming into the world of metric units. People in the U.S. who came
through the school system in the last 15 to 20 years have been indoctrinated in
SI units (Le
Système International d'unités) and do not have the problem (although far too
many are not proficient with either system of units).
Just as with gaining
fluency in a foreign language, the trick is to not be always in the habit of mentally
translating between units of measurement; rather, one must conceptualize the new
units fundamentally just as familiarization with former units was adopted. "Total
emersion" is key. Admittedly, it took me a long time to accomplish the aforementioned.
At 49 years old, I have worked in the engineering environment long enough that when
I see a drawing call out for an M4 machine screw or a dimension of 300 mm, there
is no pause needed to perform the conversion to feet or inches. Instead, now for
300 mm, I simply think of a meter stick length and estimate a little less than a
third of it. Similarly, just as I became very familiar with the sizes of #2, #4,
#6, #8, etc., bolts, M4, M5, M6, etc., sizes are automatically registered. Did I
mention it took a long time to do this?
Realizing that the majority of the
rest of the civilized world had already adopted or was in the process of adopting
the metric system, the U.S. Government passed no fewer than four laws in an attempt
to force the populace to conform. The Metric Conversion Act of 1975 (later amended
by the Omnibus Trade and Competitiveness Act of 1988, the Savings in Construction
Act of 1996, and the Department of Energy High-End Computing Revitalization Act
of 2004) designated the metric system as the preferred system of weights and measures
for U.S. trade and commerce. It mandated that federal agencies set an example by
converting to the metric system. Contractors for the government were "encouraged"
to conform as well by requiring that proposals and deliverable products be submitted
using metric units. That is akin to the Fed not being able to set highway speed
limits, but threatening to withhold highway funds if the states did not comply.
"Resistance is futile," as Hal famously uttered.
When the first metric system
bill was enacted in 1975, I was in my senior year of high school. By then, a lot
of my time had been spent drawing plans for model airplanes, rockets, and houses
(I originally started out in architectural engineering), so a very deep-rooted bias
had set into the gray matter. My neurons were distinctly English, not SI. Change
has been hard. Fortunately, all my experience with electricity and motors has not
suffered the same mental indignity because electrical units have not changed much
in my lifetime: amperes, volts, and Ohms have not changed.
Having not traveled
much outside the U.S., there really never has been an occasion where the world of
SI units unavoidably imposed itself on me, as it would with a trip to Europe. In
most areas in Canada (a notable exception being Quebec), road signs display distances
and speeds in both English and SI units. Fittingly, the incident that really drove
home the reality that not everyone considered English units as basic and metric
as a second language was a business trip to Canada a few years ago. I worked as
an RF engineer for Agilent at the time, and our customer was a well-known company
that makes the world's most famous PDA that popularized mashing tiny little QWERTY
keypad buttons with fat thumbs at a high rate of speed. We designed and installed
the production RF test fixtures for their PDAs. Anyway, while there I would listen
to their engineers speak as naturally in units of meters and liters as we here in
America do of feet and quarts. What really drove the point home was when one of
the guys was waxing nostalgic of some antics he had pulled in chemistry class that
involved the use of a "meter stick." Now, I had never owned a meter stick (and still
do not) – all my "sticks" were a yard in length. I had been drinking out of liter
bottles of soda for quite a while so it was not so strange to see them in the stores
there, but a "meter stick?" The event was obviously significant enough for me to
recall and write about it here. Pathétique, n'est-ce pas?
(in deference, here, to the Québécois in the audience).
So, even though
I still speak English [units] around the house and at family gatherings, I am very
comfortable speaking and writing SI in public. Now, when my unenlightened friends
are with Melanie and me at a restaurant where the menu is in SI units and the waiter
speaks only in SI units, I can impress them by doing the ordering for everyone.
Conversion to metric has certainly been met with varying degrees of enthusiasm
here, and has caused its share of problems – not the least of which was the total
loss of NASA's
Mars Climate Orbiter due to an oversight on the part of the programmers, who
neglected to do necessary units conversions from English to metric. We Americans
are not alone, however. I refer you to this paper released by the UK Metric Association
(UKMA) in 2004, called "A
Very British Mess," regarding the need to complete UK metrication. Misery loves
English units hard-liners have proposed an alternative to the millimeter
called the "decimal inch." The decimal inch divides the standard inch up into hundredths
of an in rather than the 1/2N fractions. They exploit the fact that the
human eye can only resolve distances down to around 1/100th of an inch, so most
people will never need to express distances to any greater precision. This facilitates
simpler mathematical operations without forcing the abandonment of the beloved inch.
It does nothing, however, to mitigate the inconvenience of a foot being a third
of a yard (being the length of a certain king's arm), and 1/5,280th of a mile. Nice
With all the progress that has been made, we here in America still buy
gasoline by the gallon, take medicine by the teaspoonful, drive at speeds of miles
per hour, and speak of putting on extra pounds at Christmas because of all the good
food. It is hard for a people who used good 'ole English units to put a man on the
moon, discover the cure for polio, create the first digital computers, pioneer powered
flight, and invent the telephone to be convinced there is any reason to change their
ways. Just because the rest of the world uses metric was not a good enough motivation
to change. Progress is steady, though, as we buy food products marked with ridiculous
quantities marked on the package. My cereal box says it contains 17.3 ounces in
order to retain the three significant digits when converting from 490 grams. My
soup can has 18.8 ounces (or 533 g) of chunky beef stuff. Cat food comes in 5.50
oz. (156 g) cans. An exponential domination of globalism - love it or hate it –
will probably be the force that obliges the total adoption. At the time of this
writing, the RF Café homepage poll indicates that there is a 2:1 preference for
SI units over English units. I suppose I am ready.
An Internet search will
turn up a multitude of inane and outdated units systems, most of which have been
abandoned long ago. Some are worth mentioning just because of their weirdness.
Furlong/Firkin/Fortnight (FFF) system of units, for example, contains units
of length and time that are at least familiar to most of us; who hasn't joked about
giving the speed of something in units of furlongs (1/8 mile) per fortnight (2 weeks)?
What the heck is a Firkin, though? Glad you asked: It is a unit of mass
equal to 8 imperial gallons of water. That all sounds so nautical. A Warhol
is equal to 15 minutes, as in
dictum, "everyone will be world-famous for fifteen minutes."
Not all units
are exact. A city block, for example, can be anywhere between 1/16 and
1/8 mile (0.1 and 0.2 km). The sydharb defines the volume of water in the
Sydney Harbour, which is around 500 gigalitres (400,000 acre-feet). A dol
measures pain – definitely subjective since it is where pain is first noticeable.
The noy is a unit of loudness in a specific frequency band; if the sound
exceeds a certain level, it is anNOYing.
Some units are so ambiguous as to
be indefinable. How expensive is, for example, "about the price of a cup of coffee,"
or how fast is, "the blink of an eye?" What quantity of something is contained in
a "boatload?" If you just took a "ration of s***" from someone, exactly how much
s*** did you just take in, say, units of kilograms or liters?
Our high tech
era has brought about its own unique unit: the nanoacre. A nanoacre is
about 4 mm2 and is used to express surface area on integrated circuits.
According to The Jargon File, "The term gets its humor from the fact that VLSI
nanoacres have costs in the same range as real acres in Silicon Valley once one
figures in design and fabrication-setup costs." A shake is precisely 10
nanoseconds, and is used in nuclear physics to define a very small unit of time.
In computing, a jiffy is the duration of one clock cycle. High energy physics types
have set the jerk equal to 1 gigajoule. A nibble is 1/2 byte (4 bits).
The Gillette quantified the strength of early rear earth (ruby) lasers,
being the energy required to burn through a Gillette razor blade.
fans might recall this exchange:
Marge: "Now, I know you haven't liked some
of my past suggestions, like switching to the metric system."
Abe: "The metric
system is the tool of the devil! My car gets forty rods to the hogshead and that's
the way I likes it."
Here is a formerly ambiguous unit that I just now defined:
Too Long. "Too long" is a written work that is precisely one word less
than the length of this Kirt's Cogitation. That definitely makes this missive "too