the 60W light bulb misconception

"Mortimer" <[email protected]> wrote in message
news:[email protected]...
> "R. Mark Clayton" <[email protected]> wrote in message
> news:[email protected]...
>
>
> To make a fair comparison, I suppose you should look at the sun's power
> *over the range of frequencies that mobile phones use* rather than over
> the whole RF to X-ray range which I think is what you were talking about
> with the 1-2 kW/sq m.

The centre of the sun's radiation is roughly yellow light.

>
> I would have thought that even if you take this into account, the sun
> proably emits more radiation than a mobile phone over the same range of
> frequencies, but I don't know whether that's true.

It is what is absorbed by a human that would be the question.

Suffice it to say that the sun has macro heating effects in infra red etc.
so I would suspect that the incident radiation in uwave would be in the
order of watts.

>
>
>
> And what's the incident power from the leakage of microwaves from a
> microwave oven if you are standing next to it? Is it true that this can
> often be higher than that from a wireless network when you are next to the
> router or the PC's wireless adaptor? Hence the interference that some
> microwave ovens cause to wireless networks, restricting the choice of
> available channels.

Fairly low, but you will suffer damage from macro effects if you run a
magnetron exposed (e.g. interfere with oven interlock or climb up a big
transmitter).
>
>

---

› See More: the 60W light bulb misconception

"R. Mark Clayton" <[email protected]> wrote in message
news:[email protected]...
>
>> And what's the incident power from the leakage of microwaves from a
>> microwave oven if you are standing next to it? Is it true that this can
>> often be higher than that from a wireless network when you are next to
>> the router or the PC's wireless adaptor? Hence the interference that some
>> microwave ovens cause to wireless networks, restricting the choice of
>> available channels.
>
> Fairly low, but you will suffer damage from macro effects if you run a
> magnetron exposed (e.g. interfere with oven interlock or climb up a big
> transmitter).

What frequency and power did WWII radar use? My grandpa used to tell me how
you could put your hand over the end of the waveguide between the
transmitter and the aerial (presumaby if you took the waveguide apart) and
fell your hand get hot fairly quickly. Probably didn't do his hand (or any
other part of his body!) much good.

Mortimer wrote:

> "R. Mark Clayton" <[email protected]> wrote in message
> news:[email protected]...
> >
> >> And what's the incident power from the leakage of microwaves from a
> >> microwave oven if you are standing next to it? Is it true that this can
> >> often be higher than that from a wireless network when you are next to
> >> the router or the PC's wireless adaptor? Hence the interference that some
> >> microwave ovens cause to wireless networks, restricting the choice of
> >> available channels.
> >
> > Fairly low, but you will suffer damage from macro effects if you run a
> > magnetron exposed (e.g. interfere with oven interlock or climb up a big
> > transmitter).
>
> What frequency and power did WWII radar use? My grandpa used to tell me how
> you could put your hand over the end of the waveguide between the
> transmitter and the aerial (presumaby if you took the waveguide apart) and
> fell your hand get hot fairly quickly. Probably didn't do his hand (or any
> other part of his body!) much good.

WW2 radars operated over a wide range of wavelengths. From 'metric' for the
likes of the British Chain Home 'early warning' system to centimetric for
magnetron based radars.

If it was waveguide then somewhere around 10cm ( 3 GHz ) typically IIRC.

Peak power was very high - up to 10kW for even the earliest magnetrons but the
pulse duration was only a few microseconds. Average power was probably in the
tens of watts. Enough to warm your hand though !

Graham

In message <[email protected]>
"Gizmo." <[email protected]> wrote:

>
> "Lenny" <[email protected]> wrote in message
> news:[email protected]...
>
> You take ****wittery to the extreme.
>
>
> > typical values of which, in the case of GSM, range from about 40 to 60.
> > If we use an optimistic figure of 30
> 40 to 60 ... figure of 30 ... what ? Turnips? carrots? dog ****?

If no unit is specified, we have to take it that it's a simple
factor.

If we're going to point out what an idiot Lenny is, we have to
get it right ourselves.

Dave

"Eeyore" <[email protected]> wrote in message
news:[email protected]...
>
>
> Mortimer wrote:
>
>> What frequency and power did WWII radar use? My grandpa used to tell me
>> how
>> you could put your hand over the end of the waveguide between the
>> transmitter and the aerial (presumaby if you took the waveguide apart)
>> and
>> feel your hand get hot fairly quickly. Probably didn't do his hand (or
>> any
>> other part of his body!) much good.
>
> WW2 radars operated over a wide range of wavelengths. From 'metric' for
> the
> likes of the British Chain Home 'early warning' system to centimetric for
> magnetron based radars.
>
> If it was waveguide then somewhere around 10cm ( 3 GHz ) typically IIRC.
>
> Peak power was very high - up to 10kW for even the earliest magnetrons but
> the
> pulse duration was only a few microseconds. Average power was probably in
> the
> tens of watts. Enough to warm your hand though !

It was (I think) Chain Home: Danby Beacon in the North York Moors, anyway.

On Sun, 05 Aug 2007 22:06:31 +0100, Eeyore
<[email protected]> wrote:

>WW2 radars operated over a wide range of wavelengths. From 'metric' for the
>likes of the British Chain Home 'early warning' system to centimetric for
>magnetron based radars.

Even the Chain Home radars managed a Megawatt (peak) at 30 MHz. GCI
Radars at 200MHz generally ran about 100kW

>If it was waveguide then somewhere around 10cm ( 3 GHz ) typically IIRC.
>Peak power was very high - up to 10kW for even the earliest magnetrons but the
>pulse duration was only a few microseconds.

10kW is way to low, even the AR1 found on every airfield ran 2 x
650kW transmitters at the same time. Pulse lengths varied from one
microsecond for shorter range radars to 150 microseconds.

Most of the 3GHz radars ran about 500kW peak, once you got into the
50's the type 84 at 1.2GHz ran 2.5MW. The 1966 Type 85 (Blue Yeoman)
ran an eye watering 54MW at about 3GHz out of 12 transmitters with an
_average_ power of up to 20kW.

Amazing how none of these mysterious "clusters" of variegated
ailments never occurred around them or in people working on them.

--
Peter Parry.
http://www.wpp.ltd.uk/

Mortimer wrote:

> "Eeyore" <[email protected]> wrote in message
> > Mortimer wrote:
> >
> >> What frequency and power did WWII radar use? My grandpa used to tell me
> >> how you could put your hand over the end of the waveguide between the
> >> transmitter and the aerial (presumaby if you took the waveguide apart)
> >> and feel your hand get hot fairly quickly. Probably didn't do his hand (or
> >> any other part of his body!) much good.
> >
> > WW2 radars operated over a wide range of wavelengths. From 'metric' for
> > the likes of the British Chain Home 'early warning' system to centimetric
> for
> > magnetron based radars.
> >
> > If it was waveguide then somewhere around 10cm ( 3 GHz ) typically IIRC.
> >
> > Peak power was very high - up to 10kW for even the earliest magnetrons but
> > the pulse duration was only a few microseconds. Average power was probably
> in
> > the tens of watts. Enough to warm your hand though !
>
> It was (I think) Chain Home: Danby Beacon in the North York Moors, anyway.

Ah. This one ?
http://homepage.ntlworld.com/don.burluraux/rafdanby.htm

That does look like Chain Home. That's not microwave as it happens but I suppose
they may have had some microwave stuff too.

The microwave stuff even got fitted to some WW2 fighters and bombers.

Graham

"Peter Parry" <[email protected]> wrote in message
news:[email protected]...

> Amazing how none of these mysterious "clusters" of variegated
> ailments never occurred around them or in people working on them.

Shh if you tell Lenny that radar is microwave he will want all airports
closed too.
But it is odd that even though microwave radiation has been around for
decades people are only sensitive to WiFi and mobile phones.

Peter Parry wrote:

>
> Most of the 3GHz radars ran about 500kW peak, once you got into the
> 50's the type 84 at 1.2GHz ran 2.5MW.

The main T84 development was around 1960 - 61 with the prototype being
installed, in 1962.

--
Old Codger
e-mail use reply to field

What matters in politics is not what happens, but what you can make
people believe has happened. [Janet Daley 27/8/2003]

Mortimer wrote:

> "Eeyore" wrote
>
> It was (I think) Chain Home: Danby Beacon in the North York Moors, anyway.

http://maps.google.com/?ie=UTF8&ll=5...&t=k&z=18&om=1

You can only make out the roads that were left behind now.

Graham

Peter Parry wrote:

> Eeyore wrote:
>
> >WW2 radars operated over a wide range of wavelengths. From 'metric' for the
> >likes of the British Chain Home 'early warning' system to centimetric for
> >magnetron based radars.
>
> Even the Chain Home radars managed a Megawatt (peak) at 30 MHz. GCI
> Radars at 200MHz generally ran about 100kW
>
> >If it was waveguide then somewhere around 10cm ( 3 GHz ) typically IIRC.
> >Peak power was very high - up to 10kW for even the earliest magnetrons but the
> >pulse duration was only a few microseconds.
>
> 10kW is way to low, even the AR1 found on every airfield ran 2 x
> 650kW transmitters at the same time. Pulse lengths varied from one
> microsecond for shorter range radars to 150 microseconds.

These weren't microwave though. The previous poster mentioned waveguides, hence
microwave kit.


> Most of the 3GHz radars ran about 500kW peak,

Not in WW2 they didn't ! I got the figure of 10kW from E.G. Bowen's book 'Radar
Days'. That was the one out of the first batch of 12 made by GEC with 8 cavities
instead of 6 (there's a long story about that). The 6 cavity ones were apparently
only good for 6kW.
http://en.wikipedia.org/wiki/Magnetron#History

Graham

Peter Parry wrote:

> Amazing how none of these mysterious "clusters" of variegated
> ailments never occurred around them or in people working on them.

Naval radars can apparently cook seagulls in flight.

Graham

On 2007-08-05, Ivor Jones <[email protected]> wrote:
> "R. Mark Clayton" <[email protected]> wrote in
> message news:[email protected]
>> "Brian Gregory [UK]" <[email protected]> wrote in message
>> news:[email protected]...
>> > So you think the 60W is for each carrier do you?
>> >
>> > Just exactly why would the mast need to be able to
>> > transmit to phones that were so far away that they
>> > haven't a hope in hell of being able to transmit back
>> > to the mast with their tiny 4W peak transmitters??
>>
>> 1W on GSM. Higher on analog (6W) but not in handheld
>> (0.6W).
>
> ISTR 900MHz GSM are 2W max and 1800 1W, which may go some way to
> explaining our old friend Jim's dislike of 1800 MHz systems ;-)

Those are the legal limits, but with a normal teeny-tiny handheld
handset you'll be lucky if it puts out more than about 0.25W average,
if that much. Since the radio link with the tower has reciprocal
performance in both directions, the output power used by the
tower to talk to the phone won't be much more than that.

There is a GSM bag phone available in the USA for use in rural
areas (the Motorola M800) which runs at the full legal 2W/1W limit.
It weighs about 4 pounds. You need significant batteries to
support that power output.

Dennis Ferguson

"Eeyore" <[email protected]> wrote in message
news:[email protected]...
>
>
> Peter Parry wrote:
>
>> Amazing how none of these mysterious "clusters" of variegated
>> ailments never occurred around them or in people working on them.
>
> Naval radars can apparently cook seagulls in flight.
>
> Graham
>

any evidence of this, or purely anecdotal?

tony h wrote:

> "Eeyore" wrote
> > Peter Parry wrote:
> >
> >> Amazing how none of these mysterious "clusters" of variegated
> >> ailments never occurred around them or in people working on them.
> >
> > Naval radars can apparently cook seagulls in flight.
>
> any evidence of this, or purely anecdotal?

I've heard it claimed in the electronics groups. It was alleged that they could
'shoot down' birds with their radar beams.

Graham