What is the efficiency of a laser device like nowadays?

I went to a 3D TV IEEE demo back in the 1970's where the device looked
like a TV but had "depth". Kind of like those kids puppet theatres! The
big thing I remember at the time was the huge power consumption
(1000-2000W?) needed to produce even a moderately lit picture. It was
said at the time that the appliance would probably never be marketed as
a 3DTV in every house would flatten the electricity supply system every
time a football/crickrt match was on!

I cant quite remember the physics or name behind the 3D technique. Some
kind of inteference pattern generation maybe. The name escapes me...

Cheers Bob VK2YQA

Spike wrote:


Powered as it is by AAA cells, it seems to have
a greater power, and a greater reserve of power, than
those laserpointers powered by watch batteries.

The shortest Google search would have turned up the information needed
to avoid him making such an obvious statement. A CR2032 battery has a
capacity of 220 mAh at a current drain of 0.2 m/A.A modern AAA battery
far exceeds that - I've left it as an exercise for the OP to search
for that info..

Your underlying motivatiopn to pooh-pooh makes you
seem like a fool.

It is the optical path that determines the divergence, or otherwise
of the beam, by dispersion, diffraction, refraction mechanisms,
and not the coherence of the radiation.

(Cue rejoinder by Mrs.Nugatory, given 5 minutes or so, to look
things up on google, to say that monochomatic radiation is
unaffected by a dispersive medium.)

Brian Reay wrote:
"Plod's Conscience" wrote in message
oups.com...

Allowing for the lens that is used to produce the
straight line beam, the spot from the end was
easily picked out on a gravestone 1/4 mile away,
thus suggesting that a tight beam is being produced.


Laser's are coherent sources, the "ASER" stands for Amplification by
Stimulated Emission of Radiation- the crucial phenomena in the operation of
lasers and masers. The emitted photon is in phase with the stimulating
photon.

"Plod's Conscience" wrote in message
ups.com...
Your underlying motivatiopn to pooh-pooh makes you
seem like a fool.


Someone offers you genuine information, on topic to your post, and you see
it as "pooh-pooh". I can see why you are a "slow learner", to use your own
description of yourself.

It is the optical path that determines the divergence, or otherwise
of the beam, by dispersion, diffraction, refraction mechanisms,
and not the coherence of the radiation.


Eh, no.

A laser will diverge in the absence of a medium.

Degree of collimation and coherence both are factors in divergence and you
are jumbling together a raft of factors that I supect you don't understand
and I know you don't want to learn about.

--
73
Brian
www.g8osn.org.uk

Your underlying motivation to pooh-pooh and to utter rather
silly and childish remarks makes you seem like a fool.

Why do you behave in that way?


Brian Reay wrote:
Someone offers you genuine information, on topic to your post, and you see
it as "pooh-pooh". I can see why you are a "slow learner", to use your own
description of yourself.

A laser will diverge in the absence of a medium.
Degree of collimation and coherence both are factors in divergence and you
are jumbling together a raft of factors that I supect you don't understand
and I know you don't want to learn about.

"The Baird system has been superceded by more modern techniques. In
fact,
unless you catch up quick, you may miss out a whole generation of
technical
improvements that have occured since "Stookie" "

An offer of genuine information?

Or the result of a deeply-seated motivation to want to cause
insult?

Stupid boy.

Brian Reay wrote:

Someone offers you genuine information, on topic to your post, and you see
it as "pooh-pooh". I can see why you are a "slow learner", to use your own
description of yourself.

Well, you're the expert in behaving like that, and as you
practised it for over 20 years, it probably accounts for
it being uppermost in your mind.

How come you never managed to pass a 12 WPM Morse
Test targetted at 14-year-olds in all that time?

Are you, perhaps, too lazy or too stupid, or both?

How come your objection to a Morse Code exam
being used as a filter to control access to HF suddenly
disappeared when a test down at your level, ie, targetted
at 6-year-olds, came along?

Hypocrisy, perhaps?

"Do as I say and not as I do", perhaps?

Bull****ting and downright lying, perhaps?

Is such two-faced behaviour that to be expected from
all directors of the RSCB?

Brian Reay wrote:
.....a raft of factors that I supect you don't understand
and I know you don't want to learn about.

Your deep-seated motivation to pooh-pooh just serves to
make you look a fool.

If you, as a director of the RSCB unfailingly try to put down
discussion, then perhaps it is a sign that any self-respecting
_REAL_ Radio Ham should resign from the RSCB?

There are many things which have "been done" and yet which
you do. (Apart from a Morse Code test that had "been done"
by otherwise-unqualified self-taught 14-year-olds).

HF Communication had "been done" by thousands, long before
you purchased all the Cheque-Book (CB) rigs that you boast about.

I don't think that I have ever been "interesed", whatever that may
mean.

Brian Reay wrote:
"Plod's Conscience" wrote in message
oups.com...

As these beasties come in a mounting that already
has facilities for screw fixing, perhaps there is
potential capability for optical communications?

Been done. UK record, as of a couple of years back at least, was something
like 75km. There is project in the latest RSGB handbook (if you are
interesed I'll look up the page, I noticed the article but haven't read the
detail).

On Sun, 12 Mar 2006 09:22:37 GMT, "Brian Reay"
wrote:

As these beasties come in a mounting that already
has facilities for screw fixing, perhaps there is
potential capability for optical communications?

Been done. UK record, as of a couple of years back at least, was something
like 75km. There is project in the latest RSGB handbook (if you are
interesed I'll look up the page, I noticed the article but haven't read the
detail).


The current UK laser record is around 73km I believe... held by G0MFR
and G8LSD. They used standard low power red laser diodes of the kind
found in the pointers. Barry,G8AGN, Gordon G0EWN and myself (all in
Sheffield) are also experimenting on these lines have done a 45km path
so far... using cw. We have some LOS paths up here in the North up to
136km so we're hoping to better the record one day soon :-)

Peter, G3PHO

On Sun, 12 Mar 2006 09:22:37 GMT, "Brian Reay"
wrote:

As these beasties come in a mounting that already
has facilities for screw fixing, perhaps there is
potential capability for optical communications?

Been done. UK record, as of a couple of years back at least, was something
like 75km. There is project in the latest RSGB handbook (if you are
interesed I'll look up the page, I noticed the article but haven't read the
detail).


The current UK laser record is around 73km I believe... held by G0MFR
and G8LSD. They used standard low power red laser diodes of the kind
found in the pointers. Barry,G8AGN, Gordon G0EWN and myself (all in
Sheffield) are also experimenting on these lines have done a 45km path
so far... using cw. We have some LOS paths up here in the North up to
136km so we're hoping to better the record one day soon :-)

Peter, G3PHO

On Tue, 14 Mar 2006 21:50:29 GMT, (Peter)
wrote:

The current UK laser record is around 73km I believe... held by G0MFR
and G8LSD.


Whooops! G0MFR should read G0MRF ... sorry Dave!

peter, G3PHO