Is this true or false

[Merlin3189]

If we use radio waves from space, no one could complain (except, perhaps the little green men!) The cosmic background radiation is probably too weak to help much, but here on earth we receive signals in the 400- 800 TeraHertz band which have powers around 100 W/sq metre or more. A little receiver of a few sq cm could easily give a few 10's of mW (enough to charge a mobile phone) and I believe several far eastern manufacturers already produce these receivers.

The main problem with these waves is that they do not penetrate the Earth to any great extent, so you can only receive them strongly when your part of the world is facing the transmitter.

 

[(*steve*)]

Some governments have been providing large subsidies to place these antennae all over your roof.

 

[CDRIVE]

If we use radio waves from space, no one could complain (except, perhaps the little green men!) The cosmic background radiation is probably too weak to help much, but here on earth we receive signals in the 400- 800 TeraHertz band which have powers around 100 W/sq metre or more.

I'm afraid to ask where you garnered this glittering jewel of misinformation.

Chris

 

[davenn]

If we use radio waves from space, no one could complain (except, perhaps the little green men!) The cosmic background radiation is probably too weak to help much, but here on earth we receive signals in the 400- 800 TeraHertz band which have powers around 100 W/sq metre or more. A little receiver of a few sq cm could easily give a few 10's of mW (enough to charge a mobile phone) and I believe several far eastern manufacturers already produce these receivers.

The main problem with these waves is that they do not penetrate the Earth to any great extent, so you can only receive them strongly when your part of the world is facing the transmitter.

definately more garbage info

please supply links to this supposed source of power

edit.... the ONLY thing in space that provides more than a few Watts of either heat or light is the sun ( over 1000W / sqr metre)..... BUT even its RF output measured at the Earth's surface is very minimal

Dave

 

[(*steve*)]

Dave, check the frequency of visible light

 

[davenn]

Dave, check the frequency of visible light

yeah thats why I did my edit earlier right after my initial post

I did suspect that's what he was referring to and I corrected his power level figure

Dave

 

[CDRIVE]

Wow! Over 1000W / sqr meter (in space) is significant power! All we need is a long extension cord and we're good to go. If Ben Franklin only knew!

Chris

 

[davenn]

Wow! Over 1000W / sqr meter (in space) is significant power! All we need is a long extension cord and we're good to go. If Ben Franklin only knew!

Chris

No, thats at the earth's surface

this is one set of figures but not the one I was looking for....

The total amount of energy received at ground level from the sun at the zenith is 1004 watts per square meter, which is composed of 527 watts of infrared radiation, 445 watts of visible light, and 32 watts of ultraviolet radiation

Note the word Zenith at higher latitudes when the sun is lower in the sky, the energy received is of course lower. The figure Merlin was suggesting a bit over 100W/sqr metre is the averaged amount over the whole sunlit side

cheers
Dave

 

[CDRIVE]

So how does this translate to available RF energy that can be rectified and stored?

Chris

 

[BobK]

It does not, unless you have some very fast rectifiers! On the other hand, solar panels work nicely.

Bob

 

[CDRIVE]

Then this this most certainly confirms the poor efficiency of solar panels because no solar panel is going to deliver anywhere near 1000W/sq meter of electrical power.

Chris

 

[BobK]

Yep:

Solar Panel (Wikipedia)

Currently the best achieved sunlight conversion rate (solar panel efficiency) is around 20.1% in new commercial products[3] typically lower than the efficiencies of their cells in isolation. The most efficient mass-produced solar panels[disputed – discuss] have energy density values of up to 16.22 W/ft2 (175 W/m2).[4]

bolding mine.

Bob

 

[CDRIVE]

Better to heat water with the Sun.

Chris

 

[Merlin3189]

definately more garbage info

please supply links to this supposed source of power

edit.... the ONLY thing in space that provides more than a few Watts of either heat or light is the sun ( over 1000W / sqr metre)..... BUT even its RF output measured at the Earth's surface is very minimal

Dave

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

Apologies for my frivolous reply. I thought most people would cotton on.
As for my amount, "100W/sqmetre or more", I had in mind a figure for the UK of around 350W/sqm which I had seen quoted, but as it was a cold, miserable, cloudy day here (so I was sat inside reading this lot!) I felt it necessary to downrate it a bit!
The link gives much more detail than I know.
If they're right and there is about 1kW/sqm perpendicular to the sun at the Earth's surface, I wonder why I'm so cold in winter? The sun is near horizontal, I'm 2m tall (true!) and about 30cm wide, so standing vertically I should get about 600W, but it doesn't feel like it! Perhaps I need to lean over about 15 degrees to get truly perpendicular. I could achieve this by drinking about half a bottle of scotch - but then I probably wouldn't need the sun to keep me warm (half bottle whiskey ~= 3MJ)

But we probably shouldn't be talking about this sort of stuff here, as I've just noticed this is not the general chat forum.

 

[CDRIVE]

But we probably shouldn't be talking about this sort of stuff here, as I've just noticed this is not the general chat forum.

Actually I'm not so sure about that. This seems to be one of our favorite topics. We just need an official law of physics that this would fall under.

Chris