New SETI technique filters out Earth interference to focus on extraterrestrial signals only...

[server]

On Wed, 19 Jul 2023 10:54:16 +0100, Martin Brown
<\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 19/07/2023 10:35, Jan Panteltje wrote:

Maybe analyzing earth transmissions from say far away, Mars? would show we have 50 Hz and 60 Hz mains..
so reverse that.. look for power lines related frequencies?

You actually see light power so the flicker of 50/60Hz mains depending
on which hemisphere your are looking at (or both in Japan) is a 100Hz or
120Hz signal in the luminosity. That\'s one way dark sky detectors work
by measuring backscatter of street lighting (as opposed to natural sky
glow).

Those 100/120 flashes/s are not that obvious. The national grids are
three phase with 120 degrees between phases. When connecting single
phase loads to the grid, one tries to get similar loading on each
phase, thus there will be 300 or 360 light pulses each second.

The light output from an incandesce lamp does not drop in a
millisecond or two, the drop might be more pounced with gas discharge
lamps- LED lamps with simple capacitor supply may show some
variations, but PWM based no variations.

Continental Europe is in one synchronous network, but UK, Scandinavia
and Russia have their own network each with own phase shifts.

If the foreign observer could limit the view to Continental Europe
only, some variation might be detectable, but if the view contains the
whole continent or hemisphere, I doubt any frequency information could
be extracted.

 

[John Larkin]

On Wed, 19 Jul 2023 20:40:36 +0300, upsidedown@downunder.com wrote:

On Wed, 19 Jul 2023 10:54:16 +0100, Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

On 19/07/2023 10:35, Jan Panteltje wrote:

Maybe analyzing earth transmissions from say far away, Mars? would show we have 50 Hz and 60 Hz mains..
so reverse that.. look for power lines related frequencies?

You actually see light power so the flicker of 50/60Hz mains depending
on which hemisphere your are looking at (or both in Japan) is a 100Hz or
120Hz signal in the luminosity. That\'s one way dark sky detectors work
by measuring backscatter of street lighting (as opposed to natural sky
glow).

Those 100/120 flashes/s are not that obvious. The national grids are
three phase with 120 degrees between phases. When connecting single
phase loads to the grid, one tries to get similar loading on each
phase, thus there will be 300 or 360 light pulses each second.

There were office fires that started in partitions, in the early days
of PCs not having PFC power supplies. The assumption was that the
neutral current in a 3-phase system is nominally zero, but big current
pulses don\'t overlap in time so the neutral wire fries.

The light output from an incandesce lamp does not drop in a
millisecond or two, the drop might be more pounced with gas discharge
lamps- LED lamps with simple capacitor supply may show some
variations, but PWM based no variations.

I did a science project once, sending audio via light beam, with a
flashlight bulb transmitter and a selenium solar cell receiver. It
worked.

 

[server]

On Wed, 19 Jul 2023 11:15:54 -0700, John Larkin
<jlarkin@highlandSNIPMEtechnology.com> wrote:

There were office fires that started in partitions, in the early days
of PCs not having PFC power supplies. The assumption was that the
neutral current in a 3-phase system is nominally zero, but big current
pulses don\'t overlap in time so the neutral wire fries.

The situation worsened when some 3 phase cables had thinner neutral
wire, since it was assumed that the much of the phase return currents
cancel each other.

If the single phase power supply had a conduction angle less than 60
degrees, all of the phase return current went through the neutral.
With no overlapping, the neutral current was three times a single
phase conductor current. With a thinner neutral, no wonder there was
some fires.

This could also cause problems to ground fault detection in some
buildings.

 

[Phil Hobbs]

On 2023-07-19 05:35, Jan Panteltje wrote:

On a sunny day (Wed, 19 Jul 2023 09:01:53 +0100) it happened Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote in <u9859i$229i0$1@dont-email.me>:


https://mindmatters.ai/2021/11/astronomer-et-is-more-likely-to-be-ai-than-a-to-be-a-life-form/

Though Fermi\'s paradox still looms large - why aren\'t they here yet?

Well, the Intergalactic Travel Agency has warned against visiting Planet Earth as it is infested with human beings
and those are considered extremely dangerous.

Nah, the HHGTTG say it\'s \"mostly harmless.\"

They obviously didn\'t try to make friends with the wildlife in Australia
(or southern Louisiana).

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John Larkin]

On Fri, 21 Jul 2023 10:24:39 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-07-19 05:35, Jan Panteltje wrote:
On a sunny day (Wed, 19 Jul 2023 09:01:53 +0100) it happened Martin Brown
\'\'\'newspam\'\'\'@nonad.co.uk> wrote in <u9859i$229i0$1@dont-email.me>:


https://mindmatters.ai/2021/11/astronomer-et-is-more-likely-to-be-ai-than-a-to-be-a-life-form/

Though Fermi\'s paradox still looms large - why aren\'t they here yet?

Well, the Intergalactic Travel Agency has warned against visiting Planet Earth as it is infested with human beings
and those are considered extremely dangerous.

Nah, the HHGTTG say it\'s \"mostly harmless.\"

They obviously didn\'t try to make friends with the wildlife in Australia
(or southern Louisiana).

Cheers

Phil Hobbs

Hey Phil, don\'t you start insulting my Cajun relatives. Some have been
tamed and even taught some basic English.

Can\'t say that for the aussies.

 

[Phil Hobbs]

On 2023-07-21 11:26, John Larkin wrote:

On Fri, 21 Jul 2023 10:24:39 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2023-07-19 05:35, Jan Panteltje wrote:
On a sunny day (Wed, 19 Jul 2023 09:01:53 +0100) it happened
Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote in
u9859i$229i0$1@dont-email.me>:


https://mindmatters.ai/2021/11/astronomer-et-is-more-likely-to-be-ai-than-a-to-be-a-life-form/



Though Fermi\'s paradox still looms large - why aren\'t they here yet?

Well, the Intergalactic Travel Agency has warned against visiting
Planet Earth as it is infested with human beings and those are
considered extremely dangerous.

Nah, the HHGTTG say it\'s \"mostly harmless.\"

They obviously didn\'t try to make friends with the wildlife in
Australia (or southern Louisiana).

Cheers

Phil Hobbs

Hey Phil, don\'t you start insulting my Cajun relatives. Some have
been tamed and even taught some basic English.

Can\'t say that for the aussies.

I almost understand Cajun. The near-total lack of plosives makes it a
fun challenge.

Sounds a lot better than ol\' Squeaky Dave.

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com