Digital vs Analog cordless Phone? Health Radiation is the s

[Daniel Mandic]

Michael A. Terrell wrote:

How would you use IR when it's 100°F or hotter outside?

I have never heard about that. Is there a temperature dependence going
with IR?


--
Daniel Mandic

 

[Michael A. Terrell]

Daniel Mandic wrote:

Michael A. Terrell wrote:

How would you use IR when it's 100°F or hotter outside?

I have never heard about that. Is there a temperature dependence going
with IR?

IR is heat. High temperatures mask IR signaling.

 

[Jeff Liebermann]

On Wed, 16 Jan 2013 19:35:02 +0100, Leif Neland <leif@neland.dk>
wrote:

Michael A. Terrell skrev:
borjanic@gmail.com wrote:

Hello,

I live in Canada and I need good (low or no radiation) cordless phone.


How is it supposed to work if it doesn't radiate some RF?

Infrared?

In my checkered past, I designed and built an IR paging system that
never made it to market. That's different from a cordless phone in
that the IR paging path is one way. To cover a rather large office
area, I was running 10 watts of IR into a hemispherical reflector to
get wide area coverage. It also has the problem of only allowing one
conversation (or compressed audio time slice) at a time per room. No
problem for paging, but big problems for IR. Visualize a room full of
TV sets, as found in the department stores, and expecting all the
remote controls to run simultaneously at the same time. I could have
used different "colors" of IR to get more than one channel, but the
filters are pricy. The spec was for 100 channels with 205
utilization, which means 20 different "colors". That won't happen.

To go bidirectional, I would need at least several hundred milliwatts
of IR in the handset, or less with shorter range. Also add extra
voice compression and switching circuitry, so that it simulates a full
duplex system. Compared to the typical 5mw of RF produced by various
wireless cordless phone systems, IR would be a battery hog.

Dealing with obstructions wasn't much of a problem. IR bounces nicely
off of various objects. Multiple emitters were also a big help.
However, dealing with IR interference from lighting and sunlight
through windows was not much fun. The light from these would overload
the receive phototransistor resulting in a very high baseline noise
level, which the emitter had to overcome. That's another reason why I
needed 10 watts.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Tue, 15 Jan 2013 16:41:22 -0800 (PST), borjanic@gmail.com wrote:

On Saturday, December 20, 2008 5:25:11 PM UTC-5, Charles wrote:
"lbbss" <labicff@yahoo.com> wrote in message
news:f1beef7d-0935-47e1-a28b-cad694ef8628@s16g2000vbp.googlegroups.com...
more power equals more radiation? is that correct?

I read some info on the web suggesting that the new Dect technology is
worst for you, because of the lower frequencies (1.9Ghz) affects your
cells in a negative way.

More power means more tissue heating and that (heating) is the concern. RF
heats tissues. Stick a hot dog in the microwave as a basic experiment.

Non-ionizing energy sources just do heat damage. A dozen mW or even
hundreds of them are of no concern. The temperature rise is almost
impossible to measure after it passes through thick skulls.

Hello,

I live in Canada and I need good (low or no radiation) cordless phone. I bought Siemens Gigaset A580 from Australia but my call waiting did not work in Canada, actually I had to disconnect current conversation in order to answer new incoming call. Besides that, I liked that phone because it had Eco Mode PLUS (the phone is dead now). Now the problem is that in Canada and US we can not buy Eco Mode PLUS phone, we can only buy Eco Mode which means base station is pulsing/radiating ALL THE TIME. I would appreciate if you can help me to choose a new cordless phone for my home (even if it's an older type as long as it has call display and call waiting). Please help me choose the phone and please explain what technology and why (analog, digital, 2.4GHz, 5.8GHz, etc).
Thank you in advance and I wish you good luck with your researches!
Peja

This posting is spew from 2008, but still interesting.

How low in radiation do you want? The typical cordless phone radiates
about 5 to 10 milliwatts of RF. Using an SAR model, that would be
about 0.005 to 0.01 watt/kg exposure as compared to maybe 1 watt/kg
for a cell phone. The FCC limit is 1.6 watts/kg.
<http://www.hpa.org.uk/web/HPAweb&HPAwebStandard/HPAweb_C/1195733767519>

Also, there's no connection between cell phone (and by implication
cordless phone) radiation and brain cancer. Here's the incidence of
new cases of brain and central nervous system cancers in 9 major metro
areas:
<http://802.11junk.com/jeffl/crud/brain-CNS-cancer.jpg>
Note that the graph is almost flat over the last 30 years. Since
about 1990, cell phone use has increase exponentially each year. If
there were a connection, I would expect the incidence of cancers to
have increased, which they have not.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Thu, 17 Jan 2013 19:18:48 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

IR is heat.

Nope. Long wave or far IR is heat. Short wave or near IR is ummmm...
near IR. Note that there are various division of IR:
<http://en.wikipedia.org/wiki/Infrared#Commonly_used_sub-division_scheme>

High temperatures mask IR signaling.

Nope. I can prove it with a simple test. Heat up a frying pan and
put it in front of IR receiver window in your TV, hi-fi, or whatever.
That should belch many watts of heat in the IR region. Then try using
the IR remote control. It will work because the 8000-15000 nanometer
wavelength of the IR "heat" from the frying pan is quite different
from the 850 nanometer wavelength of the IR emitter in your remote
control.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Michael A. Terrell]

Jeff Liebermann wrote:

On Thu, 17 Jan 2013 19:18:48 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

IR is heat.

Nope. Long wave or far IR is heat. Short wave or near IR is ummmm...
near IR. Note that there are various division of IR:
http://en.wikipedia.org/wiki/Infrared#Commonly_used_sub-division_scheme

High temperatures mask IR signaling.

Nope. I can prove it with a simple test. Heat up a frying pan and
put it in front of IR receiver window in your TV, hi-fi, or whatever.
That should belch many watts of heat in the IR region. Then try using
the IR remote control. It will work because the 8000-15000 nanometer
wavelength of the IR "heat" from the frying pan is quite different
from the 850 nanometer wavelength of the IR emitter in your remote
control.

Try that outdoors, in the bright sunlight where it isn't a narrow
slice of IR.

 

[Jeff Liebermann]

On Fri, 18 Jan 2013 02:43:48 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

Jeff Liebermann wrote:

On Thu, 17 Jan 2013 19:18:48 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

IR is heat.

Nope. Long wave or far IR is heat. Short wave or near IR is ummmm...
near IR. Note that there are various division of IR:
http://en.wikipedia.org/wiki/Infrared#Commonly_used_sub-division_scheme

High temperatures mask IR signaling.

Nope. I can prove it with a simple test. Heat up a frying pan and
put it in front of IR receiver window in your TV, hi-fi, or whatever.
That should belch many watts of heat in the IR region. Then try using
the IR remote control. It will work because the 8000-15000 nanometer
wavelength of the IR "heat" from the frying pan is quite different
from the 850 nanometer wavelength of the IR emitter in your remote
control.

Try that outdoors, in the bright sunlight where it isn't a narrow
slice of IR.

Yep. An IR cordless phone probably won't work outdoors.

See my comments in this thread on the IR paging system I helped
design. Solar and inside lighting interference were major problems.
The solar spectra contains plenty of near IR radiation, that does a
splendid job of trashing IR data. However, if the IR beam can be
controlled to a small spot size with lenses and filters and sunlight
excluded with baffles and shades, high speed IR data is possible. Due
to fear of RF, the local hospital has a bunch of IR ethernet links on
the rooftops. Those are great fun shooting over the freeway, where
the rising hot air from the vehicles causes all kinds of strange
propagation effects.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Daniel Mandic]

Jeff Liebermann wrote:

Also, there's no connection between cell phone (and by implication
cordless phone) radiation and brain cancer.

What do you await. A horn growing out of the head?

Long time meat consume dazzles the mind too, as per an U.K. survey.
Makes more prepared to take risks, respectively, they can't estimate
risks as good as they can while normal biological operation.


--
Daniel Mandic

 

[Michael A. Terrell]

Jeff Liebermann wrote:

On Fri, 18 Jan 2013 02:43:48 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

Jeff Liebermann wrote:

On Thu, 17 Jan 2013 19:18:48 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

IR is heat.

Nope. Long wave or far IR is heat. Short wave or near IR is ummmm...
near IR. Note that there are various division of IR:
http://en.wikipedia.org/wiki/Infrared#Commonly_used_sub-division_scheme

High temperatures mask IR signaling.

Nope. I can prove it with a simple test. Heat up a frying pan and
put it in front of IR receiver window in your TV, hi-fi, or whatever.
That should belch many watts of heat in the IR region. Then try using
the IR remote control. It will work because the 8000-15000 nanometer
wavelength of the IR "heat" from the frying pan is quite different
from the 850 nanometer wavelength of the IR emitter in your remote
control.

Try that outdoors, in the bright sunlight where it isn't a narrow
slice of IR.

Yep. An IR cordless phone probably won't work outdoors.

See my comments in this thread on the IR paging system I helped
design. Solar and inside lighting interference were major problems.
The solar spectra contains plenty of near IR radiation, that does a
splendid job of trashing IR data. However, if the IR beam can be
controlled to a small spot size with lenses and filters and sunlight
excluded with baffles and shades, high speed IR data is possible. Due
to fear of RF, the local hospital has a bunch of IR ethernet links on
the rooftops. Those are great fun shooting over the freeway, where
the rising hot air from the vehicles causes all kinds of strange
propagation effects.

The poor fools never stop to think about the broadband radiation from
our sun. I used to dread the 'Solar outages' on C-band when I worked in
CATV & broadcast. No matter how much advance warning you gave, idiots
would jam the phone lines, day after day as they lost their garbage TV
for a minute or so. The sat's EIRP was over 100W at 4 GHz, and the sun
swamped it easily.

 

[Jeff Liebermann]

On Fri, 18 Jan 2013 19:56:48 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

The poor fools never stop to think about the broadband radiation from
our sun. I used to dread the 'Solar outages' on C-band when I worked in
CATV & broadcast. No matter how much advance warning you gave, idiots
would jam the phone lines, day after day as they lost their garbage TV
for a minute or so. The sat's EIRP was over 100W at 4 GHz, and the sun
swamped it easily.

It still happens today with Ka and Ku band solar outages, when the sun
gets behind the satellite belt twice a year.
<http://en.wikipedia.org/wiki/Solar_outage>
I used to announce the solar outages on a local newsgroup for a
different reason. I live in a forest, where locating suitable
locations for a DBS dish is tricky. The easiest way is to wait for
when the sun gets behind the desired satellite, and photograph the
roof during the outage. That's where a dish will work. Here's some
of my photos for DirecTV at 101w.
<http://802.11junk.com/jeffl/pics/DBS/index.html>
Note the shadows from the tree branches on my dish indicating I have a
blockage problem. I don't post the outage predictions any more
because with the current HDTV satellite distribution, it takes 3-5
satellites for full coverage, which is impossible through all the
trees.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Michael A. Terrell]

Jeff Liebermann wrote:

On Fri, 18 Jan 2013 19:56:48 -0500, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:

The poor fools never stop to think about the broadband radiation from
our sun. I used to dread the 'Solar outages' on C-band when I worked in
CATV & broadcast. No matter how much advance warning you gave, idiots
would jam the phone lines, day after day as they lost their garbage TV
for a minute or so. The sat's EIRP was over 100W at 4 GHz, and the sun
swamped it easily.

It still happens today with Ka and Ku band solar outages, when the sun
gets behind the satellite belt twice a year.

I no longer work with any Sat, so I'm not the one that catches hell
for it when 10,000 people lose HBO on a cable system. At least with KU
band you need a smaller break in the trees than you needed with a five
meter fiberglass dish with multiple feedhorns for a CATV headend. That
was back when a 100°K LNA & 3" Heliax was common.

http://en.wikipedia.org/wiki/Solar_outage
I used to announce the solar outages on a local newsgroup for a
different reason. I live in a forest, where locating suitable
locations for a DBS dish is tricky. The easiest way is to wait for
when the sun gets behind the desired satellite, and photograph the
roof during the outage. That's where a dish will work. Here's some
of my photos for DirecTV at 101w.
http://802.11junk.com/jeffl/pics/DBS/index.html
Note the shadows from the tree branches on my dish indicating I have a
blockage problem. I don't post the outage predictions any more
because with the current HDTV satellite distribution, it takes 3-5
satellites for full coverage, which is impossible through all the
trees.

The trees here used to be thicker than that, till two years of high
hurricane activity a few years back. Now about 90% of the bigh trees
are gone, leaving the shorter & stronger trees behind.