No antennae radiate all the power fed to them!
 

Percy Picacity wrote in
:

That's energy to keep all the heat from the surrounding environment
out. In a system completely separated from hot material or radiation,
such as space, the energy is exactly the same, because of the way
temperature is defined.


Great, so there's a justification for researching superconductors in space,
no? Just when someone here assiduously claimed there was not.

No antennae radiate all the power fed to them!
 

Lostgallifreyan wrote:
wrote in :

You write like a starry eyed dreamer that believes long established
principals are going to go away simply by putting something in space.


Actually, no. My point has more to do with establishing precedent, aimed at
getting a mass public interested, so that a commercial market exists with
practical ideas for use. Many of the things we use on Earth like reliable
ballpoint pens, velcro, would not have got the same degree of interest or
development.

Nonsense.

Velcro was invented in 1948 and in extensive use well before there was
a real space program.

The ballpoint pen was invented in 1888 and in extensive use well before
there was a space program.

The "space" ballpoint pen was simply an ordinary pen build to tight
tolerances with a pressurized ink cartridge and they are a tiny
fraction of ballpoint pens sold every year as there is zero advantage
to them in gravity while being expensive.

Where do you get all this nonsense?


--
Jim Pennino

No antennae radiate all the power fed to them!
 

On 11/3/2014 3:09 PM, wrote:
rickman wrote:
On 11/3/2014 1:07 PM, wrote:
rickman wrote:
On 11/2/2014 4:11 PM, wrote:
Lostgallifreyan wrote:
wrote in :

The only external heat source in space is the Sun; solution, sun shade.


Maybe not. I just did a bit of Googling for 'superconductors in space' minus
quotes. There's a lot of statements abotu space missions ended because
required helium or hydrogen coolant ran out,

Yeah, the coolent ran out for the things that GENERATE a lot of heat
and need to be cooled more than radiation can provide. Radiative cooling
does not provide for a lot of cooling.

and also of space having latent
temperatures up to 100K, so a sun shade won't help a lot there with current
materials.

There really is no such thing as temperature in space as it is a vacuum.

That is a gross oversimplification. The temperature of space is the
temperature of the background radiation, even in a near vacuum.

That is also an simplification.

But not a gross oversimplification.

True.

Shall we go into why an ordinary thermometer exposed to the Sun at about
Earth's distance from the Sun allowed to stabilze will read the
tempurature of space as about 7 C and what are the unstated assumptions
for this to happen?

The number I found was about 4 °C. I believe it was posted with all the
assumptions...

--

Rick

No antennae radiate all the power fed to them!
 

rickman wrote in :

The reason why cooling something gets harder as it approaches
absolute zero is because the heat flow is proportional to the difference
in temperature. Even if your pump is perfect and acts as if you put the
thing being cooled in contact with a heat sink at 0 °K, the rate of heat
flow decreases as that temperature delta diminishes.


Ok, that helps. It's close to what I had in mind, though my reasoning may
still be bad. For what it's worth... if a superconductor is very cold,
needing to be so, then because there is no way to go below zero K, there are
more things hotter, than colder, so they have more effect than the shaded
space conditions. That balance might favour a need for forced cooling just to
play safe in many cases, but I accept that isolation might be fairly easy to
do, and I also accept that 77K is likely far enough above shaded space
conditions that it gives a wide margin to prevent small leaks from nearby
heat sources causing failure.

No antennae radiate all the power fed to them!
 

No antennae radiate all the power fed to them!
 

rickman wrote:
On 11/3/2014 3:09 PM, wrote:
rickman wrote:
On 11/3/2014 1:07 PM, wrote:
rickman wrote:
On 11/2/2014 4:11 PM, wrote:
Lostgallifreyan wrote:
wrote in :

The only external heat source in space is the Sun; solution, sun shade.


Maybe not. I just did a bit of Googling for 'superconductors in space' minus
quotes. There's a lot of statements abotu space missions ended because
required helium or hydrogen coolant ran out,

Yeah, the coolent ran out for the things that GENERATE a lot of heat
and need to be cooled more than radiation can provide. Radiative cooling
does not provide for a lot of cooling.

and also of space having latent
temperatures up to 100K, so a sun shade won't help a lot there with current
materials.

There really is no such thing as temperature in space as it is a vacuum.

That is a gross oversimplification. The temperature of space is the
temperature of the background radiation, even in a near vacuum.

That is also an simplification.

But not a gross oversimplification.

True.

Shall we go into why an ordinary thermometer exposed to the Sun at about
Earth's distance from the Sun allowed to stabilze will read the
tempurature of space as about 7 C and what are the unstated assumptions
for this to happen?

The number I found was about 4 °C. I believe it was posted with all the
assumptions...

I didn't see that post.

If it has already be done, so be it.


--
Jim Pennino

No antennae radiate all the power fed to them!
 

On Monday, November 3, 2014 12:32:18 PM UTC-6, gareth wrote:
wrote in message
...
On Monday, November 3, 2014 11:17:26 AM UTC-6, gareth wrote:
wrote in message
...
On Monday, November 3, 2014 11:05:11 AM UTC-6, gareth wrote:
"Lostgallifreyan" wrote in message
. ..
How many other people who are not engineers or scientists do you see
posting around here?

In discussions about short antennae, quite a few from Yankland.

I'm just a regular ole ham here. Never studied any of this stuff
in school, and don't work in any related field.
Everything I've learned, I learned on my own.

It shows.

Big talk from rraa's new purveyor of bafflegab

Read and learn a bit more.

About what? I read what I need to read in order to do whatever it is
I need to do. I don't need to read any more about small antennas in order
to deal with the likes of you. As you recall, I was probably the first one
to jump on you when you falsely claimed that small radiators are inefficient.
Anyone that has actually read up on the subject knows that that is not true.
If anyone needs to invest in some good textbooks on the subject, it's you.

No antennae radiate all the power fed to them!
 

On 11/3/2014 2:57 PM, rickman wrote:
On 11/3/2014 12:19 PM, Jerry Stuckle wrote:
The ISS is the same. You don't see the rotation because the ISS is
stationary (rotation-wise) relative to the earth, and you are observing
the earth. But if the cameras were pointed into space, you would see
the stars move as the ISS rotates.

As I read this and pictured cameras pointed to the earth as the "space"
station orbits the earth while ignoring the vastness of *space*, it
seems to be that humanity is obsessed with selfies.


LOL!

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

No antennae radiate all the power fed to them!
 

On Monday, November 3, 2014 2:01:21 PM UTC-6, rickman wrote:
On 11/3/2014 12:13 PM, wrote:
On Monday, November 3, 2014 11:05:11 AM UTC-6, gareth wrote:
"Lostgallifreyan" wrote in message
. ..
How many other people who are not engineers or scientists do you see
posting around here?

In discussions about short antennae, quite a few from Yankland.

I'm just a regular ole ham here. Never studied any of this stuff
in school, and don't work in any related field.
Everything I've learned, I learned on my own. Mainly from books,
of which I have several. I trust good textbooks a lot more than I
trust usenet jibber jabber. Usenet jibber jabber is only as good
as the qualifications of the one jabbering. Some info is good, some
is bad, and some is pure unadulterated bafflegab.

Will you do us *all* a favor and stop replying to him? You keep feeding
the tosser... er, I mean troll.

--

Rick

Why don't you kiss my differential. If I want to reply to him I will,
and I don't care if chaps the ass of every "Rick" on the planet.
No one is holding a pistol to your head making you read it.

No antennae radiate all the power fed to them!
 

Lostgallifreyan wrote:
wrote in :

Where do you get all this nonsense?


Those examples, from a BBC article sometime, and also some book on space when
I was a kid. So they were wrong... I have to ask, do you second guess
absolutely everythign you hear?

Calling nonsense nonsense is not second guessing.

The examples I gave were also mentioned in
part of a school class, so even if it wrong, it ended up part of a lot of
people's thoughts, so maybe you should berate the people who started the
mess, not the ones who ended up inheriting it.

If your education stopped when you walked out of the school house door,
that is your fault, not the schools.

There are lots of old wive's tales, urban legends, and other nonsense
a lot of people believe but quoting them without bothering to check
the veracity of them is your failing and yours alone.

If, for example, you had bothered to do a little research on the history
of the ballpoint pen, you would have discovered they were invented in
1888 but manufacturing problems keep them from becoming a common writting
tool until shortly after WWII when those problems were solved.

Once the practical problems were solved, sales of ballpoint pens took
off and they rapidly replaced quill and fountain pens.

Space had nothing to do with the commercial success of the ballpoint
or the fact that the Bic disposable is the most widely sold pen in
the world.

So if there is any lesson to be learned from this, it is that a little
research before posting is a GOOD idea.


--
Jim Pennino