wave-particle duality and TV reception
 

In article , David Woolley
wrote:
On 11/12/14 10:09, Jim Lesurf wrote:
So in practice the photon approach only matters much in some specific
fairly extreme cases. e.g. if you're trying to work with ultra low
signal levels at very high frequencies and photon shot noise becomes a
limit.

If I interpret http://www.coseti.org/9006-005.htm correctly, and using
an efficiency of 1, rather than 0.5, I get the effective noise
temperature as about 0.6K, for a DBS system. That is a lot less than
the open sky limit of 3K, and much much lower than achievable system
noise temperatures.

Happy to accept your figures. They show the reason why people generally
ignore 'photons' in RF.

FWIW I've had to take them into account in the past as my early work was on
'far infrared' detectors that were cooled to 3K or lower to work, then
pointed at a clear sky. In such cases photons may end up limiting such
measurements. And indeed, the signal being measured might be photon counted
when you move to nearer IR.

But this isn't likely to spoil your ability to watch UHF Freeview. :-)

Jim

--
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wave-particle duality and TV reception
 

Max Demian wrote:

"Bill Wright" wrote:

The whole science of RF seems to be based on wave theory. Does particle
theory have any place?

It looked as if he deliberately missed the tin cans with the red ping pong
balls.

From the look of the mangled bean cans he'd practised with the blue
golf balls beforehand.

wave-particle duality and TV reception
 

In article , Roderick Stewart
wrote:
On Thu, 11 Dec 2014 14:02:09 +0000 (GMT), Jim Lesurf
wrote:

My life's experience, all the way from childhood, would suggest that
most girls and women avoid involvement in technology because most of
them are simply not interested.

However that still may be a 'conditioned response' which is
indoctrinated long before they approach the end of schooling. The young
tend to pick up their ideas from their peers and the ones who are a
year or two older at school. Hence may be acquired as just one part of
a general social set of fitting in.

So where do their peers get it from?

Schools tend to have a set of cohorts across some years. Thus each new year
of intake tends to pick up established ways from the kids who started in
previous years.


to like. One of my favourite inspirational books is called "What do you
care what other people think?".

If you mean Feynman, I also have a copy. Alas I fear most junior school
kids won't think that way or have read a copy. More commonly, 'rebellion'
for kids is 'not agreeing with your parents/teachers' usually about
something trivial like musical taste or haircut.


What I do like to think is that I have a mind of my own so don't need to
copy other people's. If I can do this, then so can anybody else, but
look around you and see who does, and who doesn't. If what you say is
true, and "fitting in" is more important to some people than following
their own paths, then that's their choice, not anybody else's imposition.

I can't recally saying anyone was systematically and intentionally doing
it. Just that it seems common human behaviour when you colllect a range of
kids of different ages into a school and let them interact.

Jim

--
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wave-particle duality and TV reception
 

In article , Bill Wright
wrote:
Max Demian wrote:
"Bill Wright" wrote in message
...
The whole science of RF seems to be based on wave theory. Does
particle theory have any place?

It looked as if he deliberately missed the tin cans with the red ping
pong balls.


There's been a lot of stories recently about scientists fiddling their
results! Apparently a lot of them admit to it, years later.

OK, I confess that when I took my English Language O-Level I fibbed. I
didn't really want to be a train driver. I just wrote that in my essay for
effect. :-)

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
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Audio Misc http://www.audiomisc.co.uk/index.html

wave-particle duality and TV reception
 

"Bill Wright" wrote in message
...
Max Demian wrote:
"Bill Wright" wrote in message
...
The whole science of RF seems to be based on wave theory. Does particle
theory have any place?

It looked as if he deliberately missed the tin cans with the red ping
pong balls.

There's been a lot of stories recently about scientists fiddling their
results! Apparently a lot of them admit to it, years later.

At uni we learned that Mendel probably cheated in his pea breeding
experiments.

--
Max Demian

wave-particle duality and TV reception
 

On 12/12/14 13:21, brightside S9 wrote:
For reflections from non smooth surfaces, with roughness much greater
than the wavelength, the reflection is from the whole surface. But it
is not a simple(ish) mathemetical problem to analyse the resultant
reflected waves and build a picture of what gets to the receiver (for
example a viewer of reflections from rippling water). In this example
it is simpler to use the particle theory, and angle of incidence
equals angle of reflection rule.

That only applies when the surface is essentially locally flat at the
wavelength in question and is large in relation to the wavelength.

wave-particle duality and TV reception
 

On 12/12/14 13:21, brightside S9 wrote:
Unless anyone knows of some exotic
material that has a photoelectric effect when hit with RF.

masers. atomic clocks. quadrupole resonance spectroscopy. MRI.

These all tend to depend on spin flips, rather than knocking electrons out.

wave-particle duality and TV reception
 

In article , David Woolley
wrote:
On 12/12/14 13:21, brightside S9 wrote:
For reflections from non smooth surfaces, with roughness much greater
than the wavelength, the reflection is from the whole surface. But it
is not a simple(ish) mathemetical problem to analyse the resultant
reflected waves and build a picture of what gets to the receiver (for
example a viewer of reflections from rippling water). In this example
it is simpler to use the particle theory, and angle of incidence
equals angle of reflection rule.

That only applies when the surface is essentially locally flat at the
wavelength in question and is large in relation to the wavelength.

The idea that

angle of incidence = angle of reflection

is really a part of simple geometric ray theory, not of wave theory. It can
be based on either, given suitable simplifying assumptions.

Wave 'theory' actually comes in various forms which then get used according
to the circumstances. Ditto in fact for ray theories. In general physicists
and engineers dodge having to solve Maxwell's Equations if they can as it
can be a real PITA except in simple situations. So we have a gang of wave
and ray theories to pick from, depending on the case.

I used to point out in tutorials in the past that photons were far smarter
than people. They can 'solve' Maxwell's equations far more quickly when
they have to work out how to deal with hitting a window. :-)

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
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wave-particle duality and TV reception
 

Jim Lesurf wrote:

But this isn't likely to spoil your ability to watch UHF Freeview. :-)

Jim

Could we market our aerials as photon beam collectors?

Bill

wave-particle duality and TV reception
 

Jim Lesurf wrote:

Schools tend to have a set of cohorts across some years. Thus each new year
of intake tends to pick up established ways from the kids who started in
previous years.

Playground games go through the cohorts, year after year, sometimes
almost unchanged for generations.

Bill