Access Point Obstacle

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Hi every one,
I'm new bie. Is there any one knows, if there are metal obstacle such
as container. Is it possible for the access point signal to break
trough these kind of obstacle?. Thanks.


Re: Access Point Obstacle
Its on of those things really. It is very unlikely that a signal will
be passed though it. You could change the wireless frequency used my
your access point **If your AP allows it** Other manufacturers may have
a more suitable solution if they have larger antena. You could try an
external one....

James

Putu wrote:
Quoted text here. Click to load it


Re: Access Point Obstacle
Hi Putu,

You may wish to investigate the Cisco Aironet Antenna Reference Guide:

http://www.cisco.com/en/US/products/hw/wireless/ps469/products_data_sheet09186a008008883b.html

The density of the materials used in a building's construction
determines the number of walls the RF signal can pass through and still
maintain adequate coverage.

--------------------------------------------------------

Following are a few examples.

Actual effect on the RF must be tested at the site, and therefore a
site survey is suggested.

Paper and vinyl walls have very little effect on signal penetration.

Solid walls and floors and precast concrete walls can limit signal
penetration to one or two walls without degrading coverage.

This may vary widely based on any steel reinforcing within the
concrete.

Concrete and concrete block walls may limit signal penetration to three
or four walls.

Wood or drywall typically allow for adequate penetration through five
or six walls.

A thick metal wall reflects signals, resulting in poor penetration.

Steel-reinforced concrete flooring will restrict coverage between
floors to perhaps one or two floors.

--------------------------------------------------------

Recommendations for some common installation environments are outlined
below:

Warehousing / Manufacturing

In most cases, these installations require a large coverage area.

Experience has shown that an omnidirectional antenna mounted at 20 to
25 feet typically provides the best overall coverage.

Of course, this also depends upon the height of the racking, material
on the rack, and ability to locate the antenna at this height.

Mounting the antenna higher will sometimes actually reduce coverage, as
the angle of radiation from the antenna is more outward than down.

The antenna should be placed in the center of the desired coverage cell
and in an open area for best performance.

In cases where the radio unit will be located against a wall, a
directional antenna such as a patch or yagi can be used for better
penetration of the area.

The coverage angle of the antenna will affect the coverage area.

--------------------------------------------------------

Small Office / Small Retail

The standard dipole may provide adequate coverage in these areas
depending on the location of the radio device.

However, in a back corner office a patch antenna may provide better
coverage.

It can be mounted to the wall above most obstructions for best
performance.

Coverage of this type antenna depends on the surrounding environment.

--------------------------------------------------------

Enterprise / Large Retail

In most cases, these installations require a large coverage area.

Experience has shown that omnidirectional antennas mounted just below
the ceiling girders or just below the drop ceiling typically provide
the best coverage ( this will vary with stocking, type of material, and
building construction ).

The antenna should be placed in the center of the desired coverage cell
and in an open area for best performance.

In cases where the radio unit will be located in a corner, or at one
end of the building, a directional antenna such as a patch or yagi can
be used for better penetration of the area.

Also, for areas that are long and narrow-such as long rows of racking-a
directional antenna at one end may provide better coverage.

The radiation angle of the antennas will also affect the coverage area.

--------------------------------------------------------

Point-to-Point

When connecting two points together ( such as a wireless bridge ), the
distance, obstructions, and antenna location must be considered.

If the antennas can be mounted indoors and the distance is very short (
several hundred feet ), the standard dipole or mast mount 5.2 dBi
omnidirectional may be used.

An alternative is to use two patch antennas.

For very long distances ( 1/2 mi. or more ), directional high-gain
antennas must be used.

These antennas should be installed as high as possible, and above
obstructions such as trees, buildings, and so on; and if directional
antennas are used, they must be aligned so that their main radiated
power lobes are directed at each other.

Regarding a line-of-site configuration, distances of up to 25 miles at
2.4 GHz and 12 miles at 5 GHz can be reached using parabolic dish
antennas, if a clear line-of-site is maintained.

With the use of directional antennas, fewer interference possibilities
exist and there is less possibility of causing interference to anyone
else.

--------------------------------------------------------

Point-to-Multipoint Bridge

In this case ( in which a single point is communicating to several
remote points ), the use of an omnidirectional antenna at the main
communication point must be considered.

The remote sites can use a directional antenna that is directed at the
main point antenna.

--------------------------------------------------------

http://www.cisco.com/en/US/products/hw/wireless/ps469/products_data_sheet09186a008008883b.html

Hope this helps.

Brad Reese
BradReese.Com - Cisco Jobs
http://www.bradreese.com/hot-jobs.htm
1293 Hendersonville Road, Suite 17
Asheville, North Carolina  USA 28803
USA & Canada:  877-549-2680
International: 828-277-7272
Fax: 775-254-3558
AIM: R2MGrant
BradReese.Com - Cisco Power Supply Headquarters
http://www.bradreese.com/cisco-power-supply-inventory.htm


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