I would like to point out that getting the gear needn't be expensive.
Even cheaper: buy a used radio on
EBay,
or visit a local ham store or ham swap meet.
The gear you find may not be the latest and
fanciest, but there is a lot of good,
serviceable gear out there. My 2m handheld
is a Radio Shack HTX-202 - big (by modern
standards), heavy (ditto) and ugly (in the
eye of the beholder...:-),
but it's built like a tank and it works very well.
Unlike other radio services, we hams can
build our own radios. Hardly anybody
does anymore. Sad.
Going entirely from memory, wasn't it something to do with bumper height?
Yup. Read the article.
The 959 isn't the first car to be banned from
U.S. shores because of bumper height - VW of Brazil
declined to export their luscious SP-2 for
the same reason. And what they did
to later MGBs just wasn't pretty...
If the car is over 15 years old it's
not too difficult to import it in to
Canada. My main issue there would be
choosing between a Tatra 603 or a Citroen CX.:-)
I know some people who imported a Rover SD-1,
but only as a donor car to make a V8 MGB. Zoom!
While I'm not shopping for a car right now,
I figure the car I have now (a 1986 VW Jetta)
is the last gas-engined car I
will ever own. When I replace it I will
probably buy a diesel, but will want to check
out available hybrids. I really want them
to work, but feel they're not quite there yet.
I have no complaints about gas mileage, with
my car returning about 6 l/100km highway, 10 city. My car is licensed and insured as a pleasure
vehicle, and I drive it to work one day each week to
remind myself why I ride the bus the other 4 days.:-)
I've test-driven an Insight, and have ridden
in several Priuses. A taxi company here runs
a fleet of them, and a colleague drives one. He
jokes that you need a laptop and a USB cable to hotwire
his car. The first time I rode
in it I thought it was an Echo, and marvelled
at how quietly it idled. Then I saw the
display on the dash and knew better...
Slackware 3.1 is there to be found. That must be the second version of Slackware I installed. In that time I have a 25 MHz 486 with 8 MB of RAM, which was pretty fast considering the specs (I also had a 80 MHz AMD 486). Those were the days... Well I must say I'm glad we moved on:-)
I honestly don't remember what my first
version of Slackware was, except that it came
on a CD in the back of the first edition
of Slackware Unleashed, back
in 1997. It worked
fine on my 486/66 with 8 MB RAM. And it feels
like so long ago...
Only once did I try loading Linux on a 386.
I had found a 386sx machine in a dumpster,
powered
it up, found that it worked, tried a Slackware
kernel boot floppy (kernel 2.0.something),
watched the system spontaneouly reboot
part way through kernel initialization, turned
it off and cannibalized it for parts.
When I moved in July the do-I-bring-it-or-throw-it-out line
was Pentium 233MMX. So all the old 486 and P90 motherboards went in the garbage. The
P233MMX system served me well as
a grad student. I did my thesis on it, in LaTeX,
with Slackware (of course). Very nice.
...laura
Re:My favorit: "Have Spacesuit, Will Travel"
on
New Heinlein Novel
·
· Score: 1
I too got a kick out of Have Spacesuit, Will
Travel - the Wormfaces scared me, I wanted
to meet the Mother Thing, I wanted to go to
the Small Magellanic Cloud to see things for
myself, and so on. A novel of
nuts-and-bolts techie geekdom, and they
don't write too many of those anymore.
I also still like
The Moon is a Harsh Mistress,
and routinely display my Geek Credentials
(TM) by quoting from it.
I wasn't sure if I wanted to be Wyoming
Knott, or just go to bed with her.:-)
Heinlein's later stuff just didn't
for it for me. I read it anyway
at the time, but novels
like Time Enough for Love and
The Number of the Beast were too long,
too preachy, and too generally self-indulgent.
Possibly a stupid question: Does a copy-protected CD actually follow the CD specification from Philips et al.?
Depends on the copy protection the record
company used. Some copy protection schemes
do in fact mess up the CD data in a way that computer
CD drives can't read, and such CDs typically
don't have the official CD logo on them.
They did at one time, but Philips got upset
about it
and now they don't.
One recent purchase of mine (Doll Revolution by
The Bangles) says it's copy protected, and
doesn't have the CD logo on it. As
nearly as I can tell, they make it all but impossible to play it on a Windoze box unless
you use their (brain-damaged) CD player
application. My Linux box
played it without comment, and cdda2wav
ripped tracks without comment.
Another recent purchase (Unicas by
Azucar Moreno) also says it cannot be played on
a PC or Mac, but doesn't seem to incorporate any
copy protection of any kind. Go figure.
Doesn't it seem that a lengthy eight-step process for an OS upgrade could be one of linux's major pitfalls when it comes to targeting new users?
I'm not complaining, but shouldn't this be easier if linux is ever going to make it into the realm of familiarity?
As others have mentioned, downloading a kernel
and building it from scratch is only for the hardcore. Especially if it's a -test pre-release
kernel.
With that said, I just downloaded 2.6.0-test4
on to a test system (Slackware 9) and built it.
It works fine so
far - I need to upgrade the module stuff so
I can fire up things like the sound card and USB. Big deal. The ACPI stuff works properly,
which will make the system (a new-ish Compaq laptop) a lot easier to use in the field. Yippee!
Truth in Advertising Dept.: I got a kernel panic when it first booted,
which turned out to be an ELF kernel
that didn't have support for ELF executables,
making it rather difficult to fire
up init(). Silly me...really must learn to type someday!
Average users will see 2.6 when
it comes out in new distros - but unlike Redmond's
products, the hooks are
there if you want to tweak things. I think
this is a good thing.
2001 was a true science fiction film.
...
The best science fiction of late was "Contact" starring Jody Foster. That movie was lambasted as being boring and plotless.
I own 2001 on DVD (shhhh!!!!) and am
always startled at how it only just barely looks
dated, even today. There are a few things
that aren't right, but they all have an
It Just Didn't Happen That Way flavour to them.
Like the logo on the phone booth, or
the implication that the U.S.S.R. would still be
alive and well in 2001. I find
that Star Wars looks incredibly dated now.
Contact was a worthy film. It tried
- it really did - to be "the proverbial good science fiction film". They almost got
away with it. A really good try.
Even a flawed movie can be interesting and worth
watching.
...laura who thinks The Blue Danube is
excellent music to dock spaceships to, and that no radio telescope operator should be
without a recording of Classical Gas.
Oh, come on. Mars is in opposition every couple of years. Does anyone think it will look THAT much bigger and brighter subtending 25.1 seconds this year than it did in Jun 2001 subtending 20.5 seconds?
Something I've pointed out many times is that
while Mars is indeed closer than it was for the 2001
opposition, and, yes, marginally closer than
it has been in a very long time,
the view isn't all that hot for us Northern
folks, because it's quite low
in the sky, down in Aquarius. The last
opposition was worse, even before the dust storms.
While Mars won't be quite as big at the
next (2005) opposition, it will be much higher in
the sky (Aries), and the view won't be as badly
compromised by the atmosphere. I'll be ready.
I saw a report on the local news last night
that originated with CNN. The illustrations were
all Hubble pictures. I wish they would, once
in a while, use pictures more representative
of what you would actually see looking through
a telescope. If I had a penny for every
time somebody had looked through my
telescope (a 5" Synta refractor), sniffed,
and said "Is that it?"...
A bachelors shows proficiency in a field.
A masters shows thorough knowledge and capability in a field.
A Phd shows (and is) a contribution to the field.
When I did my M.A.Sc. I described things a little differently:
B.Sc.: Do XYZ.
M.Sc.: Find out something about XYZ.
Ph.D.: Based on XYZ, invent ABC.
I went back to school because I wanted
to do something different. My last pre-Masters
job ended badly and I really wondered if
I even wanted to continue in the field. I figured
some time off might help me decide. So I found
out interesting things about satellites,
wrote them up and got my degree.
My first (and so far only) post-Masters
job started with a 50% raise on my last pre-Masters
job. The margin now exceeds 100% (bonuses, y'know). I'm not complaining.
Exercise for the student: work out the required
delta V (here's a
useful reference). Compare with the
Shuttle's on-orbit delta V. It's cheaper
(and lots easier) to land and
get a fresh launch.
Introverts need to learn a
little extroversion just to get along in life.
Do we really need to be extroverted, or just pretend to be? I'm reminded of my own situation,
where I concluded
long ago that to be as introverted as I really
am would be career-limiting. So I've learned
to pretend to be extroverted when needed.
Sufficiently well that few people see if
for the act that it is.
But I'm still, deep down, an introvert: once the
situation passes and it's time to recharge,
I do it by myself. The Introvert Way.
What it does do is allow a given rocket to carry more payload than it would be able to carry if launched from a location farther north. The equator is the idea launching spot.
Almost.
There are two factors to consider:
From anywhere, launching due east is most efficient.
This places the spacecraft in an orbit whose inclination
is the same as the launch site's latitude.
The closer you are the equator, the more
assistance you get from the Earth's rotation.
So for the vast majority of commercial launches,
which are in to geostationary orbits (i.e.
zero inclination), you really do want to launch from
somewhere close to the equator
You will
note that the orbital inclination of Mir
(and now ISS)
was very close to the latitude of Baikonur
(they launch slightly north to avoid
launching over China, just in case).
Molniya-orbit satellites are routinely launched from Plesetsk
(orbital inclination = latitude = 63 degrees).
Heavy Shuttle missions are launched
due east from Kennedy (orbital inclination = latitude = 28 degrees). And so on.
The U.S.A. launches polar-orbit satellites
from Vandenberg. This is a range-safety issue,
nothing to do with orbital mechanics: you
can launch due south and there are no people
to be hit by falling debris for a very long way.
I'll sum up why the music biz is taking such a hit: "you can't put shine on shit."
There is no good new music out there. Period...
Can't say I disagree. Offer me something
worth listening to and I'll pay a fair price
for it. I'm happy to pay, because I know how
much work it is to make music (my brother
has recorded a couple of albums, described
by a former colleague as "A bar band.
A good bar band"), and if the
performers don't get paid, they'll
quit making music.
The fact that the current distribution
model doesn't work should be a challenge
to the RIAA: if nobody buys music, the RIAA
don't get their cut!
I find I buy a lot of music from places
like CDNow nowadays. I'll drop
by the local record stores to see what
(if anything) they have, but they rarely
have anything remotely interesting.
It's more a sympathy fuck than anything else
these days.
My last local CD purchase was a Greatest
Hits album by the Thompson Twins. My latest
online CD purchases include a Greatest
Hits album by Los del Rio (remember Macarena?),
Unicas by Azucar Moreno,
and Dvesti po Vstrechnoi, the original
Russian version of
Tatu's album.
Spirited but slightly flat in (obviously phonetic) English. Brilliant in Russian.
And I haven't seen any of these
titles available locally.
...laura
Re:No more car tinkering...
on
42-Volt Autos
·
· Score: 2, Interesting
However, that's not how most people are killed by electricity. What kills people is having a small current flow across their heart, causing it to fibrillate and then you die. Your skin is a reasonably good insulator, so this requires a high voltage (NOT CURRENT!)... 50v isn't enough, and even 100 volts is rarely enough. Given enough voltage, this only requires a small fraction of an amp.
Remember the old saw: "it's the volts that
jolts, but the mills that kills".
42 volts will make you jump - I work in
the telecomms industry and know what 48 feels
like - but you would have to take some
care to get enough current from a
42 volt supply
through your heart to kill you. It
would be a terribly inefficient way to commit suicide. Electric chairs typically
use about
2000 volts Amazing (and kinda sad) what you can find with Google!
I haven't been able to find anything interesting on shortwave. It's neat to be able to hear stations from all over the world, but that novelty wears out
pretty quick. All I hear are religious and non-English shows. Are all the good shows non-English? Dang it, another $200 bucks down the toilet.
Maybe I can buy a few more and make a beowulf cluster...
You just need to look a little harder. There
is lots of Really Neat Stuff on shortwave.
My favourites remain the BBC, Radio Netherlands,
and Radio Australia. The BBC are almost as
polite as us Canadians, while the Dutch have a case on
everybody. Then there are the Australians...
I find shortwave particularly handy while travelling -
particularly in the U.S., where the rest of the world
disappears as soon as I cross the border.
HF utility stations are a hoot in their own right. International
air-traffic control, weather charts from
Uzbekistan, assorted spooks, and so on. Great fun.
I feel out-geeked. The best
I can offer is programming an Altera
gate array to plug in to a 68000 processorbus and be a DRAM controller.
Languages are almost as much fun
as computers. But then I
am one of those Weird Canadians
who drove to work yesterday listening to
a Russian CD
(Tatu, 200 po vstrechnoi) and a French one (Liane Foly, Reve Orange).
TV in North America uses 54 to 88 MHz for channels 2 to 6, 174 to 216 MHz for 7 to 13, and
470 to 806 MHz for channels 14 to 68. Much
of the UHF spectrum is now shared with radio services
in big cities. Several European countries have
no VHF television at all now.
At one time UHF TV went from 470 to 890
MHz for channels 14 to 83, but the top end was
changed to various radio services (including
cellphones) some years ago.
Wavelengths:just under 6 meters at the bottom
of VHF to about 130 cm at the top. About
70 cm for channel 14 to 35 cm for channel 68.
The higher frequencies have essentially optical
line-of-sight propagation, but the lower ones
can follow terrain for a while. Unusual conditions
can affect this, including tropospheric ducting
(best on UHF), sporadic E-layer skip (VHF),
even F2 (not so much channel A2, but some
countries have TV down to 45 MHz or so).
Digital TV can be (and usually is) pretty robust in
the face of various transmission errors, but
like all such systems does not degrade gracefully. As you
get close the edge of the coverage area
of an aanalog station you get snowy pictures.
As you get close the edge of the coverage area
of a digital station you abruptly go from a perfect
picture to none at all.
Being a one-way medium digital TV doesn't
do retransmission - the station adds
error-correction informaiton to the transmission,
which the receiver uses to correct bit errors on reception. Look up "forward error correction" in any decent communications
text book. Also look up "convolutional codes", "Viterbi Algorithm",
and various other goodies.
It can run a reasonably sophisticated FI program using somewhere around 10% of the CPU!
This is a hard real-time application,
so the thing had better have spare cycles
available!:-)
While it sounds fast, car engine things
happen at ridiculously slow speeds by
computer standards. A 4 cylinder engine
running at 6000 RPM still has 5 milliseconds
between firing strokes to compute and time
the next spark. An eternity to a computer...
...laura, whose car (1986 VW Jetta) has mechanical fuel
injection and electronic (analog) ignition
There are about six billion people on earth and each person's body consists of about 100 trillion cells. With 128 bit addressing each individual cell
in every human being could have 100 trillion addresses. I believe that is on par with 1 address per molecule.
A necessary number: number of IPV6 addresses
is 2**128 = 3.4E38.
Hmmm...lessee now, 6E9 people, 1E14 cells per person, that makes 6E23 cells. That's about 5E14 IPV6 addresses (five hundred trillion) per cell.
Per molecule? Let's assume an average person's mass is 60 kg, and that the average molecular weight of the human body is 25 (we are mostly water). That makes (60 * 1000) / 25 * 6.02E23 = 1.4E27 molecules per person.
Total Earth population is then 6E9 * 1.4E27 = 8.4E36 molecules. Actually about 40 addresses per molecule.
My other favourite number is how many IPV6 addresses each
square micron of the Earth's surface could have:
Earth's surface area in square microns =
4 pi (6378 * 1000 * 1000000) ** 2 = 5.1E26
I remember writing my thesis back in early 90's. To ensure top fidelity in graphs and drawing, I hand crafted all illustrations in postscript. I got to know ps in depth:-)
I did much the same with a magazine
article I wrote a while back, because I
was too cheap to use a "real" drawing program.
Speaking of stupid PostScript tricks,
in a past life at a company that did
prepress software and printing hardware
(lots of PostScript - 500 MB was
nothing) I amused
myself by coding the Towers of Hanoi in
PostScript, as a demonstration
of what PostScipt could do. Even if I had to draw pictures
of the stack by hand to get the parameters
to the roll operator right at
each new recursion.
I think it might be younger. I think the internet switched to TCP/IP around 1983.
One indicator of this is that the relevant RFCs (791 and 793)
are dated in 1981. At the time there were
all kinds of long-haul data links, and lots
of short-haul stuff too. I remember the
University where I was an undergrad developing
their own network to connect terminals
to mainframes. Then they added X.25 capability
so you could talk to people in other places
(and boy was it expensive!). Then
they hooked it up to the Internet. Then
they ditched it completely, but
not before several hacks to hook
those new-fangled PCs up to it. At the time
I considered myself fortunate to
have a 9600 baud SLIP link.
It's clear from the earliest RFCs that
people really didn't know what computer networking was going to look like, and were
making it up as they went along. People
were certainly networking computers prior
to the final form of TCP/IP; just that the present implementation
of TCP/IP gelled the same year MTV went on the air.
Whenever I read something like this I'm
reminded of the "election" right after the
revolution in Heinlein's The Moon is a Harsh Mistress.
Everybody voted by computer, except that
all the computers were all
tied in to Mike Holmes/Adam Selene, who did the final count.
It didn't occur to the auditors that if you
feed honest figures in to a computer, the
results could still be nonsense because
the computer itself might be dishonest.
It might even have a sense of humour...
This is an excellent point and one that i was wondering about. Unlike other countries who routinely decommission monetary instruments (with a brief
trade-in period), the United States refuses to do so. Why?...
Here in Canada all Bank of Canada
notes are legal tender, and will remain so.
You are not likely to
see a George V or George VI dollar bill in
circulation, but you can still spend it. However,
when the banks send them back to the Mint,
they will be destroyed.
The Bank of Canada have
a nice web site with lots of pretty pictures.
All the notes they show are legal tender.
We are rolling out a new series of banknotes
now, with two versions of both the $5 and $10
bill in circulation. They incorporate all
the usual security goodies: weird colours,
large portraits, watermarks, embedded doodads, complicated fine-line backgrounds,
and so on.
...project it onto a piece of white paper with a pinhole camera. Then you won't get the dark glasses
obscuring your view, either. A little ingenuity often prevails over a little consumerism.;)
For the partial eclipse last June I made a pinhole
camera out of a cardboard box. I taped a piece
of white paper inside for a projection screen,
poked a tiny hole in a piece of 120 film
backing paper (black on the film side) for
the pinhole, and stuck the whole thing
together with masking tape. Total investment: 0. Images: excellent. Geek factor: very high.
I sent instructions to my sister who
made a similar device for my nieces to
see the eclipse. They were delighted.
Slashdot Mirror
Even cheaper: buy a used radio on EBay, or visit a local ham store or ham swap meet. The gear you find may not be the latest and fanciest, but there is a lot of good, serviceable gear out there. My 2m handheld is a Radio Shack HTX-202 - big (by modern standards), heavy (ditto) and ugly (in the eye of the beholder... :-),
but it's built like a tank and it works very well.
Unlike other radio services, we hams can build our own radios. Hardly anybody does anymore. Sad.
...laura VE7LDH
Yup. Read the article.
The 959 isn't the first car to be banned from U.S. shores because of bumper height - VW of Brazil declined to export their luscious SP-2 for the same reason. And what they did to later MGBs just wasn't pretty...
If the car is over 15 years old it's not too difficult to import it in to Canada. My main issue there would be choosing between a Tatra 603 or a Citroen CX. :-)
I know some people who imported a Rover SD-1, but only as a donor car to make a V8 MGB. Zoom!
...laura
While I'm not shopping for a car right now, I figure the car I have now (a 1986 VW Jetta) is the last gas-engined car I will ever own. When I replace it I will probably buy a diesel, but will want to check out available hybrids. I really want them to work, but feel they're not quite there yet.
I have no complaints about gas mileage, with my car returning about 6 l/100km highway, 10 city. My car is licensed and insured as a pleasure vehicle, and I drive it to work one day each week to remind myself why I ride the bus the other 4 days. :-)
I've test-driven an Insight, and have ridden in several Priuses. A taxi company here runs a fleet of them, and a colleague drives one. He jokes that you need a laptop and a USB cable to hotwire his car. The first time I rode in it I thought it was an Echo, and marvelled at how quietly it idled. Then I saw the display on the dash and knew better...
...laura
I honestly don't remember what my first version of Slackware was, except that it came on a CD in the back of the first edition of Slackware Unleashed, back in 1997. It worked fine on my 486/66 with 8 MB RAM. And it feels like so long ago...
Only once did I try loading Linux on a 386. I had found a 386sx machine in a dumpster, powered it up, found that it worked, tried a Slackware kernel boot floppy (kernel 2.0.something), watched the system spontaneouly reboot part way through kernel initialization, turned it off and cannibalized it for parts.
When I moved in July the do-I-bring-it-or-throw-it-out line was Pentium 233MMX. So all the old 486 and P90 motherboards went in the garbage. The P233MMX system served me well as a grad student. I did my thesis on it, in LaTeX, with Slackware (of course). Very nice.
...laura
I too got a kick out of Have Spacesuit, Will Travel - the Wormfaces scared me, I wanted to meet the Mother Thing, I wanted to go to the Small Magellanic Cloud to see things for myself, and so on. A novel of nuts-and-bolts techie geekdom, and they don't write too many of those anymore.
I also still like The Moon is a Harsh Mistress, and routinely display my Geek Credentials (TM) by quoting from it. I wasn't sure if I wanted to be Wyoming Knott, or just go to bed with her. :-)
Heinlein's later stuff just didn't for it for me. I read it anyway at the time, but novels like Time Enough for Love and The Number of the Beast were too long, too preachy, and too generally self-indulgent.
...laura
Depends on the copy protection the record company used. Some copy protection schemes do in fact mess up the CD data in a way that computer CD drives can't read, and such CDs typically don't have the official CD logo on them. They did at one time, but Philips got upset about it and now they don't.
One recent purchase of mine (Doll Revolution by The Bangles) says it's copy protected, and doesn't have the CD logo on it. As nearly as I can tell, they make it all but impossible to play it on a Windoze box unless you use their (brain-damaged) CD player application. My Linux box played it without comment, and cdda2wav ripped tracks without comment.
Another recent purchase (Unicas by Azucar Moreno) also says it cannot be played on a PC or Mac, but doesn't seem to incorporate any copy protection of any kind. Go figure.
...laura
As others have mentioned, downloading a kernel and building it from scratch is only for the hardcore. Especially if it's a -test pre-release kernel.
With that said, I just downloaded 2.6.0-test4 on to a test system (Slackware 9) and built it. It works fine so far - I need to upgrade the module stuff so I can fire up things like the sound card and USB. Big deal. The ACPI stuff works properly, which will make the system (a new-ish Compaq laptop) a lot easier to use in the field. Yippee!
Truth in Advertising Dept.: I got a kernel panic when it first booted, which turned out to be an ELF kernel that didn't have support for ELF executables, making it rather difficult to fire up init(). Silly me...really must learn to type someday!
Average users will see 2.6 when it comes out in new distros - but unlike Redmond's products, the hooks are there if you want to tweak things. I think this is a good thing.
...laura
I own 2001 on DVD (shhhh!!!!) and am always startled at how it only just barely looks dated, even today. There are a few things that aren't right, but they all have an It Just Didn't Happen That Way flavour to them. Like the logo on the phone booth, or the implication that the U.S.S.R. would still be alive and well in 2001. I find that Star Wars looks incredibly dated now.
Contact was a worthy film. It tried - it really did - to be "the proverbial good science fiction film". They almost got away with it. A really good try. Even a flawed movie can be interesting and worth watching.
...laura who thinks The Blue Danube is excellent music to dock spaceships to, and that no radio telescope operator should be without a recording of Classical Gas.
Something I've pointed out many times is that while Mars is indeed closer than it was for the 2001 opposition, and, yes, marginally closer than it has been in a very long time, the view isn't all that hot for us Northern folks, because it's quite low in the sky, down in Aquarius. The last opposition was worse, even before the dust storms.
While Mars won't be quite as big at the next (2005) opposition, it will be much higher in the sky (Aries), and the view won't be as badly compromised by the atmosphere. I'll be ready.
I saw a report on the local news last night that originated with CNN. The illustrations were all Hubble pictures. I wish they would, once in a while, use pictures more representative of what you would actually see looking through a telescope. If I had a penny for every time somebody had looked through my telescope (a 5" Synta refractor), sniffed, and said "Is that it?"...
...laura
When I did my M.A.Sc. I described things a little differently:
B.Sc.: Do XYZ.
M.Sc.: Find out something about XYZ.
Ph.D.: Based on XYZ, invent ABC.
I went back to school because I wanted to do something different. My last pre-Masters job ended badly and I really wondered if I even wanted to continue in the field. I figured some time off might help me decide. So I found out interesting things about satellites, wrote them up and got my degree.
My first (and so far only) post-Masters job started with a 50% raise on my last pre-Masters job. The margin now exceeds 100% (bonuses, y'know). I'm not complaining.
...laura
More specifically (from Celestrak)
Hubble: 28 degrees inclination
ISS: 51 degrees inclination
Exercise for the student: work out the required delta V (here's a useful reference). Compare with the Shuttle's on-orbit delta V. It's cheaper (and lots easier) to land and get a fresh launch.
...laura
Do we really need to be extroverted, or just pretend to be? I'm reminded of my own situation, where I concluded long ago that to be as introverted as I really am would be career-limiting. So I've learned to pretend to be extroverted when needed. Sufficiently well that few people see if for the act that it is.
But I'm still, deep down, an introvert: once the situation passes and it's time to recharge, I do it by myself. The Introvert Way.
...laura
Almost. There are two factors to consider:
From anywhere, launching due east is most efficient. This places the spacecraft in an orbit whose inclination is the same as the launch site's latitude.
The closer you are the equator, the more assistance you get from the Earth's rotation.
So for the vast majority of commercial launches, which are in to geostationary orbits (i.e. zero inclination), you really do want to launch from somewhere close to the equator
You will note that the orbital inclination of Mir (and now ISS) was very close to the latitude of Baikonur (they launch slightly north to avoid launching over China, just in case). Molniya-orbit satellites are routinely launched from Plesetsk (orbital inclination = latitude = 63 degrees). Heavy Shuttle missions are launched due east from Kennedy (orbital inclination = latitude = 28 degrees). And so on.
The U.S.A. launches polar-orbit satellites from Vandenberg. This is a range-safety issue, nothing to do with orbital mechanics: you can launch due south and there are no people to be hit by falling debris for a very long way.
...laura
Can't say I disagree. Offer me something worth listening to and I'll pay a fair price for it. I'm happy to pay, because I know how much work it is to make music (my brother has recorded a couple of albums, described by a former colleague as "A bar band. A good bar band"), and if the performers don't get paid, they'll quit making music.
The fact that the current distribution model doesn't work should be a challenge to the RIAA: if nobody buys music, the RIAA don't get their cut!
I find I buy a lot of music from places like CDNow nowadays. I'll drop by the local record stores to see what (if anything) they have, but they rarely have anything remotely interesting. It's more a sympathy fuck than anything else these days.
My last local CD purchase was a Greatest Hits album by the Thompson Twins. My latest online CD purchases include a Greatest Hits album by Los del Rio (remember Macarena?), Unicas by Azucar Moreno, and Dvesti po Vstrechnoi, the original Russian version of Tatu's album. Spirited but slightly flat in (obviously phonetic) English. Brilliant in Russian. And I haven't seen any of these titles available locally.
...laura
Remember the old saw: "it's the volts that jolts, but the mills that kills".
42 volts will make you jump - I work in the telecomms industry and know what 48 feels like - but you would have to take some care to get enough current from a 42 volt supply through your heart to kill you. It would be a terribly inefficient way to commit suicide. Electric chairs typically use about 2000 volts Amazing (and kinda sad) what you can find with Google!
...laura
You just need to look a little harder. There is lots of Really Neat Stuff on shortwave. My favourites remain the BBC, Radio Netherlands, and Radio Australia. The BBC are almost as polite as us Canadians, while the Dutch have a case on everybody. Then there are the Australians...
I find shortwave particularly handy while travelling - particularly in the U.S., where the rest of the world disappears as soon as I cross the border.
HF utility stations are a hoot in their own right. International air-traffic control, weather charts from Uzbekistan, assorted spooks, and so on. Great fun.
...laura
I feel out-geeked. The best I can offer is programming an Altera gate array to plug in to a 68000 processorbus and be a DRAM controller.
Languages are almost as much fun as computers. But then I am one of those Weird Canadians who drove to work yesterday listening to a Russian CD (Tatu, 200 po vstrechnoi) and a French one (Liane Foly, Reve Orange).
...laura
TV in North America uses 54 to 88 MHz for channels 2 to 6, 174 to 216 MHz for 7 to 13, and 470 to 806 MHz for channels 14 to 68. Much of the UHF spectrum is now shared with radio services in big cities. Several European countries have no VHF television at all now.
At one time UHF TV went from 470 to 890 MHz for channels 14 to 83, but the top end was changed to various radio services (including cellphones) some years ago.
Wavelengths:just under 6 meters at the bottom of VHF to about 130 cm at the top. About 70 cm for channel 14 to 35 cm for channel 68. The higher frequencies have essentially optical line-of-sight propagation, but the lower ones can follow terrain for a while. Unusual conditions can affect this, including tropospheric ducting (best on UHF), sporadic E-layer skip (VHF), even F2 (not so much channel A2, but some countries have TV down to 45 MHz or so).
Digital TV can be (and usually is) pretty robust in the face of various transmission errors, but like all such systems does not degrade gracefully. As you get close the edge of the coverage area of an aanalog station you get snowy pictures. As you get close the edge of the coverage area of a digital station you abruptly go from a perfect picture to none at all. Being a one-way medium digital TV doesn't do retransmission - the station adds error-correction informaiton to the transmission, which the receiver uses to correct bit errors on reception. Look up "forward error correction" in any decent communications text book. Also look up "convolutional codes", "Viterbi Algorithm", and various other goodies.
...laura
This is a hard real-time application, so the thing had better have spare cycles available! :-)
While it sounds fast, car engine things happen at ridiculously slow speeds by computer standards. A 4 cylinder engine running at 6000 RPM still has 5 milliseconds between firing strokes to compute and time the next spark. An eternity to a computer...
...laura, whose car (1986 VW Jetta) has mechanical fuel injection and electronic (analog) ignition
A necessary number: number of IPV6 addresses is 2**128 = 3.4E38.
Hmmm...lessee now, 6E9 people, 1E14 cells per person, that makes 6E23 cells. That's about 5E14 IPV6 addresses (five hundred trillion) per cell.
Per molecule? Let's assume an average person's mass is 60 kg, and that the average molecular weight of the human body is 25 (we are mostly water). That makes (60 * 1000) / 25 * 6.02E23 = 1.4E27 molecules per person. Total Earth population is then 6E9 * 1.4E27 = 8.4E36 molecules. Actually about 40 addresses per molecule.
My other favourite number is how many IPV6 addresses each square micron of the Earth's surface could have:
Earth's surface area in square microns = 4 pi (6378 * 1000 * 1000000) ** 2 = 5.1E26
3.4E38 / 5.1E26 = 6.6E11
A big number!
...laura
I did much the same with a magazine article I wrote a while back, because I was too cheap to use a "real" drawing program.
Speaking of stupid PostScript tricks, in a past life at a company that did prepress software and printing hardware (lots of PostScript - 500 MB was nothing) I amused myself by coding the Towers of Hanoi in PostScript, as a demonstration of what PostScipt could do. Even if I had to draw pictures of the stack by hand to get the parameters to the roll operator right at each new recursion.
...laura
One indicator of this is that the relevant RFCs (791 and 793) are dated in 1981. At the time there were all kinds of long-haul data links, and lots of short-haul stuff too. I remember the University where I was an undergrad developing their own network to connect terminals to mainframes. Then they added X.25 capability so you could talk to people in other places (and boy was it expensive!). Then they hooked it up to the Internet. Then they ditched it completely, but not before several hacks to hook those new-fangled PCs up to it. At the time I considered myself fortunate to have a 9600 baud SLIP link.
It's clear from the earliest RFCs that people really didn't know what computer networking was going to look like, and were making it up as they went along. People were certainly networking computers prior to the final form of TCP/IP; just that the present implementation of TCP/IP gelled the same year MTV went on the air.
...laura
Whenever I read something like this I'm reminded of the "election" right after the revolution in Heinlein's The Moon is a Harsh Mistress.
Everybody voted by computer, except that all the computers were all tied in to Mike Holmes/Adam Selene, who did the final count. It didn't occur to the auditors that if you feed honest figures in to a computer, the results could still be nonsense because the computer itself might be dishonest. It might even have a sense of humour...
...laura
Here in Canada all Bank of Canada notes are legal tender, and will remain so.
You are not likely to see a George V or George VI dollar bill in circulation, but you can still spend it. However, when the banks send them back to the Mint, they will be destroyed. The Bank of Canada have a nice web site with lots of pretty pictures. All the notes they show are legal tender.
We are rolling out a new series of banknotes now, with two versions of both the $5 and $10 bill in circulation. They incorporate all the usual security goodies: weird colours, large portraits, watermarks, embedded doodads, complicated fine-line backgrounds, and so on.
...laura
For the partial eclipse last June I made a pinhole camera out of a cardboard box. I taped a piece of white paper inside for a projection screen, poked a tiny hole in a piece of 120 film backing paper (black on the film side) for the pinhole, and stuck the whole thing together with masking tape. Total investment: 0. Images: excellent. Geek factor: very high.
I sent instructions to my sister who made a similar device for my nieces to see the eclipse. They were delighted.
...laura