what material reflects microwave?

Link:  http://en.wikipedia.org/wiki/File:Signalreflectors.JPG

Near Salt Lake City, UT.
Up close, you can see they have little patterns cut into them to
better reflect certain wavelengths.
They use these as passive repeaters (no electronics whatsoever) to get
around mountainous terrain and other obstructions.
Sometimes you'll see them on old microwave relay towers (antennas on
the ground, passive reflector panels at altitude on a tower)

You wouldn't think they'd work, but they actually work quite well.
I recall in the early days of the space race, they launched a metal
spehere and bounced radio waves off it while it was in orbit.
Pretty much the same concept here.

-mpm

On 08/26/2010 11:00 PM, David Eather wrote:
On 27/08/2010 7:57 AM, Tim Wescott wrote:
On 08/26/2010 02:07 PM, David Eather wrote:
On 27/08/2010 5:08 AM, Tim Wescott wrote:
On 08/26/2010 11:49 AM, jgy2001 wrote:
What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
I am thinking simple laminated material, such as film, or tape or
plastic sheets?
Can I embed simple film with some kind of simple metal to reflect
microwave signals?

Metal, or just about anything that's metalized. Aluminized mylar would
certainly count as a "simple film", and is somewhat conformal if you
don't mind cussing a bit.

If you can't find it anywhere else find a hobby shop that caters to
model airplane builders and ask for metallic Monocoat, or check out the
hobby websites (Tower Hobbies is good).

The "Emergency Space Blankets" beloved by rescue and emergency services
are aluminized mylar and cost something like one or two dollars per
square yard.

Of course! Why didn't I think of that?

(please don't answer).


I have lots of time, but little money on hand.

You could make a great close-to-parabolic reflector with one of those
things just by sticking it to a round air tight frame and pulling a
vacuum. In fact, even if the frame weren't perfectly round it'd
probably still be an OK reflector.

The downside would be that you'd need to maintain the vacuum, but hey --
nothing in life is perfect.

On Aug 27, 12:25 pm, "L. Larry" <larry.py...@gmail.com> wrote:
Thank you for all your responses.

I am interested to learn the material that reflects microwave energy,
cellular and wifi signals, and these specific wavelengths?

I also interested to learn what is best and low cost to collect
cellular and wifi specific wavelength signals?

Low cost (for collecting) would be an antenna.
High cost (for reflecting) might be something like this:

Link: http://en.wikipedia.org/wiki/File:Signalreflectors.JPG

Near Salt Lake City, UT.
Up close, you can see they have little patterns cut into them to
better reflect certain wavelengths.
They use these as passive repeaters (no electronics whatsoever) to get
around mountainous terrain and other obstructions.
Sometimes you'll see them on old microwave relay towers (antennas on
the ground, passive reflector panels at altitude on a tower)

You wouldn't think they'd work, but they actually work quite well.
I recall in the early days of the space race, they launched a metal
spehere and bounced radio waves off it while it was in orbit.
Pretty much the same concept here.

On 08/26/2010 11:49 AM, jgy2001 wrote:

What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
I am thinking simple laminated material, such as film, or tape or
plastic sheets?
Can I embed simple film with some kind of simple metal to reflect
microwave signals?

Metal, or just about anything that's metalized. Aluminized mylar would
certainly count as a "simple film", and is somewhat conformal if you
don't mind cussing a bit.

If you can't find it anywhere else find a hobby shop that caters to
model airplane builders and ask for metallic Monocoat, or check out the
hobby websites (Tower Hobbies is good).

You can also get aluminum backed duct tape (you _don't_ want 'regular'
silver-colored duct tape -- you want the stuff that looks like aluminum
foil).

Or you could make a form, spray 3M 77 contact cement on it, and apply
aluminum foil.

Come to think of it, even something like silver paint might -- although
if it did it'd probably scatter quite a bit.

--

Tim Wescott
Wescott Design Serviceshttp://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details athttp://www.wescottdesign.com/actfes/actfes.html

On Aug 27, 11:08 am, mpm <mpmill...@aol.com> wrote:







Link:  http://en.wikipedia.org/wiki/File:Signalreflectors.JPG

Near Salt Lake City, UT.
Up close, you can see they have little patterns cut into them to
better reflect certain wavelengths.
They use these as passive repeaters (no electronics whatsoever) to get
around mountainous terrain and other obstructions.
Sometimes you'll see them on old microwave relay towers (antennas on
the ground, passive reflector panels at altitude on a tower)

You wouldn't think they'd work, but they actually work quite well.
I recall in the early days of the space race, they launched a metal
spehere and bounced radio waves off it while it was in orbit.
Pretty much the same concept here.

-mpm

mpm, very interesting, can you tell me more about this kind passive
signal reflectors? If I can build something myself? how do I figure
out the patterns for WiFi and Cellular signals?- Hide quoted text -

- Show quoted text -

On Aug 27, 4:45 pm, Tim Wescott <t...@seemywebsite.com> wrote:
On 08/26/2010 11:00 PM, David Eather wrote:

You could make a great close-to-parabolic reflector with one of those
things just by sticking it to a round air tight frame and pulling a
vacuum. In fact, even if the frame weren't perfectly round it'd
probably still be an OK reflector.

The downside would be that you'd need to maintain the vacuum, but hey --
nothing in life is perfect.

Or you could take a big tank full of mercury,
and slowly rotate it so the centrifugal force makes a parabolic shape,
allowing you to dynamically adjust the focus.
It has some drawbacks, but maybe you could sell it as 'green',
and they would not notice

If I make a flat metal sheet as antenna on window from inside my
apartment, to improve sign reception and transmission, what kind of
pattern should I use for Wifi (2.45GHz) and Cellular (GSM has 4 bands,
do not know what is best frequency for rest others?)

To: miso_at_sushi.com, why spray on Nickel? Is Nickel good in absorb or
reflect microwave?

On 08/26/2010 11:49 AM, jgy2001 wrote:
What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
I am thinking simple laminated material, such as film, or tape or
plastic sheets?
Can I embed simple film with some kind of simple metal to reflect
microwave signals?

Metal, or just about anything that's metalized. Aluminized mylar would
certainly count as a "simple film", and is somewhat conformal if you
don't mind cussing a bit.

If you can't find it anywhere else find a hobby shop that caters to
model airplane builders and ask for metallic Monocoat, or check out the
hobby websites (Tower Hobbies is good).

You can also get aluminum backed duct tape (you _don't_ want 'regular'
silver-colored duct tape -- you want the stuff that looks like aluminum
foil).

Or you could make a form, spray 3M 77 contact cement on it, and apply
aluminum foil.

Come to think of it, even something like silver paint might -- although
if it did it'd probably scatter quite a bit.

On 08/26/2010 11:00 PM, David Eather wrote:
On 27/08/2010 7:57 AM, Tim Wescott wrote:
On 08/26/2010 02:07 PM, David Eather wrote:
On 27/08/2010 5:08 AM, Tim Wescott wrote:
On 08/26/2010 11:49 AM, jgy2001 wrote:
What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
I am thinking simple laminated material, such as film, or tape or
plastic sheets?
Can I embed simple film with some kind of simple metal to reflect
microwave signals?

Metal, or just about anything that's metalized. Aluminized mylar would
certainly count as a "simple film", and is somewhat conformal if you
don't mind cussing a bit.

If you can't find it anywhere else find a hobby shop that caters to
model airplane builders and ask for metallic Monocoat, or check out the
hobby websites (Tower Hobbies is good).

The "Emergency Space Blankets" beloved by rescue and emergency services
are aluminized mylar and cost something like one or two dollars per
square yard.

Of course! Why didn't I think of that?

(please don't answer).


I have lots of time, but little money on hand.

You could make a great close-to-parabolic reflector with one of those
things just by sticking it to a round air tight frame and pulling a
vacuum. In fact, even if the frame weren't perfectly round it'd
probably still be an OK reflector.

The downside would be that you'd need to maintain the vacuum, but hey --
nothing in life is perfect.

On Aug 27, 12:25 pm, "L. Larry" <larry.py...@gmail.com> wrote:
Thank you for all your responses.

I am interested to learn the material that reflects microwave energy,
cellular and wifi signals, and these specific wavelengths?

I also interested to learn what is best and low cost to collect
cellular and wifi specific wavelength signals?

Low cost (for collecting) would be an antenna.
High cost (for reflecting) might be something like this:

Link: http://en.wikipedia.org/wiki/File:Signalreflectors.JPG

Near Salt Lake City, UT.
Up close, you can see they have little patterns cut into them to
better reflect certain wavelengths.
They use these as passive repeaters (no electronics whatsoever) to get
around mountainous terrain and other obstructions.
Sometimes you'll see them on old microwave relay towers (antennas on
the ground, passive reflector panels at altitude on a tower)

You wouldn't think they'd work, but they actually work quite well.
I recall in the early days of the space race, they launched a metal
spehere and bounced radio waves off it while it was in orbit.
Pretty much the same concept here.

-mpm

On Aug 26, 1:49 pm, jgy2001 <jgy2...@gmail.com> wrote:
What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
I am thinking simple laminated material, such as film, or tape or
plastic sheets?
Can I embed simple film with some kind of simple metal to reflect
microwave signals?
Thank you.

The material that is embedded in some microwave popcorn bags (which is
why they always say "This Side Down".
Ditto for some microwave frozen dinner entres.

-mpm

On Aug 26, 12:11 pm, mpm <mpmill...@aol.com> wrote:
On Aug 26, 1:49 pm, jgy2001 <jgy2...@gmail.com> wrote:

What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
...
The material that is embedded in some microwave popcorn bags (which is
why they always say "This Side Down".
Ditto for some microwave frozen dinner entres.

Actually, that stuff (called "reluctor") doesn't _reflect_ the
microwaves - aluminum
foil does that admirably (I saw a photo shoot in an early microwave
oven cookbook -
they wrapped an ice cube in foil, set it in the oven next to a cup of
water, boiled the
water and the ice cube was virtually untouched.) But that stuff on the
bottom of the
popcorn pack is designed to _absorb_ the microwaves and turn them into
just plain
ol' heat. Sometimes you get those "hot pocket" thingies with reluctor
wrapped around
them to brown the crust.

I have a suspicion that the reluctor stuff is somehow related to
"radar-absorbent
materal" paint for stealth aircraft. ;-)

Cheers!
Rich

On Thu, 26 Aug 2010 12:08:40 -0700, Tim Wescott <tim_at_seemywebsite.com
wrote:

On 08/26/2010 11:49 AM, jgy2001 wrote:
What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
I am thinking simple laminated material, such as film, or tape or
plastic sheets?
Can I embed simple film with some kind of simple metal to reflect
microwave signals?

Metal, or just about anything that's metalized. Aluminized mylar would
certainly count as a "simple film", and is somewhat conformal if you
don't mind cussing a bit.

If you can't find it anywhere else find a hobby shop that caters to
model airplane builders and ask for metallic Monocoat, or check out the
hobby websites (Tower Hobbies is good).

You can also get aluminum backed duct tape (you _don't_ want 'regular'
silver-colored duct tape -- you want the stuff that looks like aluminum
foil).

Or you could make a form, spray 3M 77 contact cement on it, and apply
aluminum foil.

Come to think of it, even something like silver paint might -- although
if it did it'd probably scatter quite a bit.

A lot of "silver" paints contain NO metal.

On Fri, 27 Aug 2010 07:45:58 -0700, Tim Wescott <tim_at_seemywebsite.com
wrote:

On 08/26/2010 11:00 PM, David Eather wrote:
On 27/08/2010 7:57 AM, Tim Wescott wrote:
On 08/26/2010 02:07 PM, David Eather wrote:
On 27/08/2010 5:08 AM, Tim Wescott wrote:
On 08/26/2010 11:49 AM, jgy2001 wrote:
What kind of simple material reflects microwave energy, such as
cellular and wifi signals?
I am thinking simple laminated material, such as film, or tape or
plastic sheets?
Can I embed simple film with some kind of simple metal to reflect
microwave signals?

Metal, or just about anything that's metalized. Aluminized mylar would
certainly count as a "simple film", and is somewhat conformal if you
don't mind cussing a bit.

If you can't find it anywhere else find a hobby shop that caters to
model airplane builders and ask for metallic Monocoat, or check out the
hobby websites (Tower Hobbies is good).

The "Emergency Space Blankets" beloved by rescue and emergency services
are aluminized mylar and cost something like one or two dollars per
square yard.

Of course! Why didn't I think of that?

(please don't answer).


I have lots of time, but little money on hand.

You could make a great close-to-parabolic reflector with one of those
things just by sticking it to a round air tight frame and pulling a
vacuum. In fact, even if the frame weren't perfectly round it'd
probably still be an OK reflector.

The downside would be that you'd need to maintain the vacuum, but hey --
nothing in life is perfect.

Pretty much any air pressure differential, use the other hookup on the
household vacuum, and then spray the back with structural foam. After
it hardens you are good to go.