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Global positioning



 
 
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  #21  
Old February 17th 18, 08:35 AM posted to uk.tech.digital-tv
Jeff Layman[_2_]
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Posts: 723
Default Global positioning

On 16/02/18 17:01, Jim Lesurf wrote:

We need energy and to me nuclear fision is the only viable
option before fusion which will always be 20+ years away.


I take a more mixed view. That renewables are a useful addition to the mix.
That pro tem, yes, we probably need to use fission power. And that in the
end we'll probably either have to limit our power useage or get fusion.

As for the fusion timescale, we're winning if it now down to 20 years away!
It always used to be 50 years away. :-)

I'm currently waiting to see what happens to some of the new novel small
scale tokomacs, etc.


We've been using a lot more fusion power recently. Last time I looked,
solar power *was* fusion power. It's just that it's not very efficient
from that far away (not in our latitudes anyway!).

I'm not holding my breath waiting for earth-based fusion power. I reckon
we'd have more chance of large arrays of space-based solar cells
generating microwave power and transmitting that to earth.

Maybe it's something Elon Musk should look at now he's got something
viable to get it up there, and we know how he loves renewables.

--

Jeff
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  #22  
Old February 17th 18, 09:08 AM posted to uk.tech.digital-tv
Jim Lesurf[_2_]
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Posts: 4,326
Default Global positioning

In article , Jeff Layman
wrote:

We've been using a lot more fusion power recently. Last time I looked,
solar power *was* fusion power. It's just that it's not very efficient
from that far away (not in our latitudes anyway!).



True, but given cheap enough solar collectors, etc, can be a useful
addition. The efficiency/cost of these have continued to rise. Note also
the recent IEEE 'Spectrum' article on using windows as energy collectors at
low cost.

Given how much income the Arabian area gets from oil I wonder if they might
start putting up solar farms on a large scale with dc lines to the north,
so they can sell us their sunshine. :-) The capital costs are high, but
then so are the costs of oil wells, multi-thousand mile pipelines, etc.

I'm not holding my breath waiting for earth-based fusion power. I reckon
we'd have more chance of large arrays of space-based solar cells
generating microwave power and transmitting that to earth.


The snag with that I suspect is people being suspicious of having orbiting
stations that can transmit down multi-megawatt beams. I've seen worries
ranging from "It might harm birds that fly through the beam" to "that might
make a serious weapon" expressed. However as engineering it remains
possible. Not sure about the politics.

But in principle, yes, they are an interesting idea. Another snag is that -
as with conventional views of fusion - they require a big expensive
facility. The ideas about small scale tocomaks might allow much smaller
generators - cheaper and easier to have distributed around the country
where most convenient.

it occurs to me from the above that it might be possible to 'cubesat'
orbital power recovery from the sun. Just build a fleet of small sats, then
use them as a phased array to send down the power to where it is needed. No
need for one large physical antenna or collector. I've not seen anyone else
mention this idea, but it seems obvious now it has come to mind.

Potentially, could also work with different 'investors' adding their own
set of cubesats to such a fleet and then taking the relevant percentage of
the demand/income. Orbital version of the grid authority required. :-)

Jim

--
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  #23  
Old February 17th 18, 09:23 AM posted to uk.tech.digital-tv
Brian Gaff
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Posts: 7,250
Default Global positioning

Sigh, In fact the concept of all those things is explainable without going
into the detail.I don't think many teachers understand things enough to go
to the conceptual level on modern stuff.
Brian

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"Jim Lesurf" wrote in message
...
In article , Jeff Layman
wrote:

Yes and no. How far do you go? I can understand a mechanical clock
turning its gear wheels around and measuring time that way, but what
about a digital clock. especially one connected via radio to an atomic
clock? Where do you start - vibrating Caesium atoms? Then radio theory,
then integrated circuits? Etc, etc. It all reminds me of that terrible
time when children go through that "Why?" phase. They ask why something
is the way it is; you explain it, but that leads to another "Why?", and
so on.


When they ask "Why?" questions, tell them you will only answer "How?"
ones.
Then explain that people have written millions of books containing most of
the answers. If you can, then take them to the library. :-)

Teach a man to fish...

Another 'dumbing down' factor in the UK now is the rapid loss of local
libraries, and the drying up of funds that lets those which remain buy
more
books.

Jim

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Please use the address on the audiomisc page if you wish to email me.
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Audio Misc http://www.audiomisc.co.uk/index.html



  #24  
Old February 17th 18, 09:35 AM posted to uk.tech.digital-tv
Norman Wells[_6_]
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Posts: 984
Default Global positioning

On 17/02/2018 09:35, Jeff Layman wrote:
On 16/02/18 17:01, Jim Lesurf wrote:

We need energy and to me nuclear fision is the only viable
option before fusion which will always be 20+ years away.


I take a more mixed view. That renewables are a useful addition to the
mix.
That pro tem, yes, we probably need to use fission power. And that in the
end we'll probably either have to limit our power useage or get fusion.

As for the fusion timescale, we're winning if it now down to 20 years
away!
It always used to be 50 years away. :-)

I'm currently waiting to see what happens to some of the new novel small
scale tokomacs, etc.


We've been using a lot more fusion power recently. Last time I looked,
solar power *was* fusion power. It's just that it's not very efficient
from that far away (not in our latitudes anyway!).


Actually, it's far more than people realise.

It's been calculated that the total amount energy used in the world is
the same as the total solar energy falling on just the US interstate
highway system.

http://landartgenerator.org/blagi/archives/127

That's assuming 100% conversion of course, but it's illustrative.

Even in the UK, annual solar energy falling per square metre is close to
1000 kilowatt-hours, which is really quite a lot.

I'm not holding my breath waiting for earth-based fusion power.


Very sensible.

I reckon
we'd have more chance of large arrays of space-based solar cells
generating microwave power and transmitting that to earth.


There's really no need when we have so much energy available at ground
level.
  #25  
Old February 17th 18, 09:45 AM posted to uk.tech.digital-tv
Roderick Stewart[_3_]
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Posts: 2,246
Default Global positioning

On Fri, 16 Feb 2018 19:20:35 +0000, Jeff Layman
wrote:

I expect that most SatNav systems enable tracking by default. I turned
this off on mine as soon as I found the SatNav recorded where I'd been,
or whether this really does stop it recording. I also have no idea
whether or not this "history" could be uploaded when the SatNav is
updated. Most modern cars now have a wifi connection (some via any
connected smartphone) so who can tell what is uploaded, and where it is
uploaded to?


Your satnav device probably contains not only a history of where it's
been, but a list of memorised locations so you can easily program them
repeatedly without typing all the details in every time. The list
probably includes one called "Home".

Whether anything can be uploaded or not, if anybody steals your car
they'll know where you live, or will be able without much difficulty
to work it out. I guess this is just something we have to live with as
part of the modern world.

Rod.
  #26  
Old February 17th 18, 10:24 AM posted to uk.tech.digital-tv
Andy Burns[_12_]
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Posts: 573
Default Global positioning

Norman Wells wrote:

It's been calculated that the total amount energy used in the world is
the same as the total solar energy falling on just the US interstate
highway system.


There are those who take that as a suggestion that the best place to put
the solar panels is *in* the freekin roads ...

  #27  
Old February 17th 18, 10:46 AM posted to uk.tech.digital-tv
Indy Jess John
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Posts: 1,307
Default Global positioning

On 17/02/2018 10:35, Norman Wells wrote:

It's been calculated that the total amount energy used in the world is
the same as the total solar energy falling on just the US interstate
highway system.

http://landartgenerator.org/blagi/archives/127

That's assuming 100% conversion of course, but it's illustrative.


The estimate that I saw was that if the entire Sahara Desert was covered
in solar panels at today's conversion efficiency, that would generate
enough power to meet the total energy demands of the continent of Europe.

It is an interesting thought, but I can't see it ever happening.

Jim
  #28  
Old February 17th 18, 11:11 AM posted to uk.tech.digital-tv
Indy Jess John
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Posts: 1,307
Default Global positioning

On 16/02/2018 19:20, Jeff Layman wrote:

I can understand a mechanical clock
turning its gear wheels around and measuring time that way, but what
about a digital clock. especially one connected via radio to an atomic
clock? Where do you start - vibrating Caesium atoms? Then radio theory,
then integrated circuits?


I had this conversation some years ago with the editor of an electronics
magazine. I complained that all the published circuits had little boxes
for ICs, and previously the magazine had published circuits using
discrete components like transistors and resistors etc, so that it was
possible to see exactly why the circuit worked as described.

He replied that the modern microprocessor had many thousand on-board
components and it was neither practical to find the space to print such
a circuit nor to expect the typical magazine reader to work out the
paths through it.

He missed the point that the vast majority of the circuits had simpler
chips like Op Amps and 555_Timers and the like, and a series of "How
things work" for the most popular chips would have given a useful
insight into the magic performed by these ICs. It would also have given
readers with a drawer full of discrete components the opportunity to
replicate the function of a chip without actually using the chip.

I eventually gave up buying the magazine. All the fun had gone out of it.

Jim
  #29  
Old February 17th 18, 11:37 AM posted to uk.tech.digital-tv
Jeff Layman[_2_]
external usenet poster
 
Posts: 723
Default Global positioning

On 17/02/18 10:35, Norman Wells wrote:
On 17/02/2018 09:35, Jeff Layman wrote:

I reckon
we'd have more chance of large arrays of space-based solar cells
generating microwave power and transmitting that to earth.


There's really no need when we have so much energy available at ground
level.


Yes and no. As Jim (IJJ) mentioned, we could probably get what we needed
with the Sahara used as a generation site. But there's at least two
problems with all land-based generation. The first is the weather (less
with the Sahara I grant you), and the second is the Earth's rotation.
And with only half the day available for generation we need much better
energy storage methods, unless you're convinced that the power lines
will extend around the world and everyone will get what they need - day
or night.

--

Jeff
  #30  
Old February 17th 18, 01:14 PM posted to uk.tech.digital-tv
Jim Lesurf[_2_]
external usenet poster
 
Posts: 4,326
Default Global positioning

In article , Jeff Layman
wrote:

Yes and no. As Jim (IJJ) mentioned, we could probably get what we needed
with the Sahara used as a generation site. But there's at least two
problems with all land-based generation. The first is the weather (less
with the Sahara I grant you), and the second is the Earth's rotation.
And with only half the day available for generation we need much better
energy storage methods, unless you're convinced that the power lines
will extend around the world and everyone will get what they need - day
or night.


Yes, energy storage is a significant part of what will be required. But it
is also something which people are working on, taking various tacks.

e.g. the recent idea that the batteries in electric vehicles can be used to
store energy when connected to the grid. i.e. not all the capacity, all of
the time for every vehicle is always needed for travel. But can be held for
grid support at other times. Given millions of vehicles and a suitable grid
control that may be useful. In effect, the vehicle owner gets cheaper
energy by 'renting' its use for such purposes.

As with other ideas, it is unlikely one single method will solve every
problem. But a set of novel ideas may well combine to make a significant
difference.

And there are, IIUC, already dc links right across Europe and into nearby
countries. Thus covering many time zones and different weather conditions.
Such links seem likely to be more common and longer-reaching.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa...o/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

 




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