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Old November 2nd 14, 11:00 PM posted to rec.radio.amateur.antenna
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Default No antennae radiate all the power fed to them!

On 11/2/2014 4:20 PM, Lostgallifreyan wrote:
rickman wrote in :

Sort of like wrestling a pig. You
get all dirty and the pig enjoys it.


That's the one I was trying to remember last week.


Actually, I think it goes, "You both get dirty, but the pig enjoys it."

--

Rick
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Old November 2nd 14, 11:02 PM posted to rec.radio.amateur.antenna
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Default No antennae radiate all the power fed to them!

Jerry Stuckle wrote in news:m36d06$ui2$1@dont-
email.me:

Assuming this equation is correct, the temperature of the object
described is just 4 °C at Earth's orbit. Of course the earth is warmer
because it is warmed from the inside as well as from the sun.


That's part of it. But it's also because the Earth doesn't radiate all
that well, either. It holds a fair amount of the heat that strikes it.
Air is a great insulator


Also, greenhouse efeect, skewing the ratio of heat gained vs heat lost... The
UK just had a half-week of mid summer temps at Halloween. Never mind 'weather
vs climate', these recordsd are being broken all the time now.
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Old November 2nd 14, 11:05 PM posted to rec.radio.amateur.antenna
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Jerry Stuckle wrote:
On 11/2/2014 4:17 PM, wrote:
On Sunday, November 2, 2014 1:51:46 PM UTC-6, Jerry Stuckle wrote:

No, I don't think any part of the ISS is in "constant shadow". I
believe it rotates as it orbits the earth, and different parts of it are
in the shade at different times. I could be wrong, though - I've never
been there


Hard to say.. Some parts away from the sun may stay dark during a
daylight pass, but they may be lit on other passes, depending on
the direction and angles to the sun. I suspect they want to keep the
solar panels towards the sun as much as possible, but the panels
themselves may be steerable to some degree.
I've never been there in person, but I've been there via camera
on many an orbit. Watching the planet from that platform can be
good wholesome entertainment for the whole family.


I also don't know how steerable the solar panels are - but I would
expect them to be somewhat steerable. It wouldn't make a lot of sense
to keep having to adjust the position of the entire ISS to keep the
panels aimed at the sun.

The station itself does not really appear to roll at all.
Or at least that can be detected on a lit pass, and using the
earth as a "roll indicator" of sorts.


But if it keeps one direction pointed towards Earth, then it has to roll
- one rotation per orbit. Which means the solar panels have to be
steerable to some extent for maximum power.

But anyone can watch for themselves as long as they are in
contact, and not on a nighttime pass. The cameras they are using
don't seem to be too sensitive at night. IE: I hardly ever notice
the lights below on a dark pass. Of course, they zip around the
planet in about 90 minutes time.. So quite a few chances during a
day to see what parts of the station are lit, and which are not.
Some cameras, like the one I'm watching right now do not show the
station at all, while the one they were using a few minutes ago did.
At this moment they are fixing to pass into darkness over the Atlantic.

http://eol.jsc.nasa.gov/HDEV/
http://www.ustream.tv/channel/iss-hdev-payload


The ISS rolls once per orbit keeping a constant attitude toward Earth.

http://www.collectspace.com/ubb/Foru...ML/001224.html



--
Jim Pennino
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Old November 2nd 14, 11:07 PM posted to rec.radio.amateur.antenna
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Default No antennae radiate all the power fed to them!

rickman wrote in :

That's the one I was trying to remember last week.


Actually, I think it goes, "You both get dirty, but the pig enjoys it."


Precision in all things. It's right, I'm getting memories of the context I
first saw that now. The guy it was used for was a troll according to many,
but one that changed a great deal for the better. He was a lot younger
though...

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Old November 2nd 14, 11:11 PM posted to rec.radio.amateur.antenna
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Jerry Stuckle wrote:
On 11/2/2014 3:58 PM, wrote:
Lostgallifreyan wrote:
wrote in :

Apples and oranges; we already know what will happen if one were to
build an antenna from a superconductor.

Fire up EZNEC and set material loss to zero; done.


Yeah, anyone with a map could say a great deal about the shape of West Africa
based on ocean travel.


Again, apples and oranges as we know EXACTLY and in DETAIL what would happen.

My point isn't so much about antennas, as about
exploring the easy availability of cold environments for superconductors in
space.


Easy availability measured in thousands of dollars an ounce to get
stuff there.

Not having to lug heavy coolers up there might be an offer someone
cannot refuse, and that someone might come back with all kinds of
discoveries, things no models or predictions are going out there to find.


The only thing that makes a superconductor different is the lack of
resistance.

We already know exactly what that means and what we would do with them
if room temperature superconcductors were available.

Here are a couple of things: electric motors and generators that would
be very close to 100% efficient, small, light, and lossless power
transmission lines, lossless transformers, big honking magnets.


It's a little more than just no resistance. For instance,
superconductors will "reflect" (for lack of a better word) a magnetic
field. That's now a superconducting disk will levitate over a magnetic
field. So just setting the resistance to zero doesn't necessarily cut
it. There are other things to consider which EZNIC may not handle properly.


Such as?

In regards to magnetic levitation, a super conductor is a perfect
diamagnet due to the Meissner effect.

None of that has anything to do with antennas.

http://hyperphysics.phy-astr.gsu.edu...ds/maglev.html

http://en.wikipedia.org/wiki/Magnetic_levitation

--
Jim Pennino


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Old November 2nd 14, 11:16 PM posted to rec.radio.amateur.antenna
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Default No antennae radiate all the power fed to them!

On 11/2/2014 6:02 PM, Lostgallifreyan wrote:
Jerry Stuckle wrote in news:m36d06$ui2$1@dont-
email.me:

Assuming this equation is correct, the temperature of the object
described is just 4 °C at Earth's orbit. Of course the earth is warmer
because it is warmed from the inside as well as from the sun.


That's part of it. But it's also because the Earth doesn't radiate all
that well, either. It holds a fair amount of the heat that strikes it.
Air is a great insulator


Also, greenhouse efeect, skewing the ratio of heat gained vs heat lost... The
UK just had a half-week of mid summer temps at Halloween. Never mind 'weather


Recorded temperatures have always set new records. Just considering one
location, there are 365 days in a year and so 730 high and low records
to test. We have been recording temperatures for roughly 200 years.
What are the chances we *won't* set a new record for one of those dates
in a given year?

--

Rick
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Old November 2nd 14, 11:18 PM posted to rec.radio.amateur.antenna
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Default No antennae radiate all the power fed to them!

On 11/2/2014 3:58 PM, wrote:
Lostgallifreyan wrote:
wrote in :

Apples and oranges; we already know what will happen if one were to
build an antenna from a superconductor.

Fire up EZNEC and set material loss to zero; done.


Yeah, anyone with a map could say a great deal about the shape of West Africa
based on ocean travel.


Again, apples and oranges as we know EXACTLY and in DETAIL what would happen.

My point isn't so much about antennas, as about
exploring the easy availability of cold environments for superconductors in
space.


Easy availability measured in thousands of dollars an ounce to get
stuff there.

Not having to lug heavy coolers up there might be an offer someone
cannot refuse, and that someone might come back with all kinds of
discoveries, things no models or predictions are going out there to find.


The only thing that makes a superconductor different is the lack of
resistance.


That is far from true. There are all sorts of magnetic effects.


We already know exactly what that means and what we would do with them
if room temperature superconcductors were available.

Here are a couple of things: electric motors and generators that would
be very close to 100% efficient, small, light, and lossless power
transmission lines, lossless transformers, big honking magnets.



--

Rick
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