10dbi antenna, useless

Hi all
i bought a pci 10dbi omni antenna, it said it will increase
250%-300%. But i don't see any different either the range or the
signal strong.

http://www.planex.com.tw/product/soh...nt-in-10-b.htm

thanks
from Peter (cmk128@hotmail.com)

On 7 May 2007 19:04:17 -0700, cmk128@hotmail.com wrote in
<1178589857.930120.276230@e65g2000hsc.googlegroups .com>:

> i bought a pci 10dbi omni antenna, it said it will increase
>250%-300%. But i don't see any different either the range or the
>signal strong.
>
>http://www.planex.com.tw/product/soh...nt-in-10-b.htm

A 10 dBi omni can improve range by that amount, but has a narrow
vertical pattern width that can be hard to aim.

What are you trying to accomplish?

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Can a Wireless 2.4ghz @ 1 watt can be dangerous to use at home




On Tue, 08 May 2007 04:24:24 GMT, John Navas
<spamfilter1@navasgroup.com> wrote:

>On 7 May 2007 19:04:17 -0700, cmk128@hotmail.com wrote in
><1178589857.930120.276230@e65g2000hsc.googlegroup s.com>:
>
>> i bought a pci 10dbi omni antenna, it said it will increase
>>250%-300%. But i don't see any different either the range or the
>>signal strong.
>>
>>http://www.planex.com.tw/product/soh...nt-in-10-b.htm
>
>A 10 dBi omni can improve range by that amount, but has a narrow
>vertical pattern width that can be hard to aim.
>
>What are you trying to accomplish?

cmk128@hotmail.com wrote:
> Hi all
> i bought a pci 10dbi omni antenna, it said it will increase
> 250%-300%. But i don't see any different either the range or the
> signal strong.
>
> http://www.planex.com.tw/product/soh...nt-in-10-b.htm
>
> thanks
> from Peter (cmk128@hotmail.com)
>

Rather than keep posting that "x" doesn't do this and "y" doesn't do
that why don't you post what it is that you wish to achieve and what
equipment you, at present, have available. You may find that someone has
a solution to the problem.

cmk128@hotmail.com hath wroth:

>Hi all
> i bought a pci 10dbi omni antenna, it said it will increase
>250%-300%. But i don't see any different either the range or the
>signal strong.
>
>http://www.planex.com.tw/product/soh...nt-in-10-b.htm

Increase what 300%. Signal strength, range, price?

I'll assume your PCI device is in the open and not in the usual
location, buried behind a steel PC box, under a desk, amid a tangle of
wires, low on the ground, and generally in the worst possible RF
location. Since it's a vertical antenna, it can't be too close to the
metal case or it will detune. It has to be almost perfectly vertical
as the bulk of the RF comes out perpendicular to the line of the
antenna. In other words, it's almost impossible to properly mount
such an antenna on the back of a metal PC box. The antenna also
doesn't offer any better "penetration" than your previous antenna. If
you have a mess of obstructions along the line of sight, such as
wires, walls, furniture, doors, and junk, more gain is helpful, but
not a guaranteed improvement.

Let's play with the math. (Math is fun).
The antenna claims 10dBi gain.
Range doubles for every 6dBi of gain.
Your existing antenna probably is a 2dBi rubber ducky.
Your net improvement in gain is 10dBi - 2dBi = 8dBi.
8dBi is good for:
range increase = 10^(dB/20) = 10^(8/20) = 2.5 times
So, you should see a 2.5x increase in range, but only after you've
eliminated all the other problems and obstructions previously listed.

I suggest you consider a coax cable extension for you PCI card to get
the antenna out of the tangle of wires and away from any obstructions.
The improvment in location will more than compensate for the added
coax cable loss.

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