Can you help me roughly CALCULATE how to increase the range of my home
Internet wireless WiFi setup to a shed 300 feet away from my house?

Presently, I can walk about half the way through the wooded area to the
shed with my laptop in hand before I lose the connection to the PCMCIA
802.11b,g Linksys card. Basically I need to gain 150 feet in "range".

But how?

At the store, I immediately become confused as I try to compare $30 USD
omnidirectional antennas (D-Link ANT24-070) that boost "power" by a claimed
7 db; $50 USD directional corner antennas (Hawking HAI15SC) that claim 15
dbi (whatever a dBi is); and $150 USD 802.11N routers that claim to boost
omnidirectional "range" by 4x (Linksys WRT300N).

How does an omnidirectional 7 db or directional 15 dBi boost in "power"
equate to range?

Approximately how many decibels of (omnidirectional or directional) power
do I really need to boost my WiFi range from about 150 feet to the 300 feet
I need?

Looking up what a decibel is
(http://en.wikipedia.org/wiki/Decibel#Definition), I
calculate the D-Link ANT24-070 omnidirectional antenna gives me about 5
times the power (assuming 7 db = 10^7/10 ~= 5); but does this get me the
additional 150 feet of range to my shed?

Spending almost twice as much money on the Hawking HAI15SC directional
antenna gets me roughly 30 times the power (assuming 15 db = 10^15/10 ~=
32); but is that enough power to get me the range to my shed?

Indeed, is there some way to add a Hawking 15db antenna on the receiving
end to get 1,000 times the power (15 db + 15 db = 30 db = 10^30/10 ~=
1,000); but what would I hook the wire output from this receiving antenna
to in the shed (I can't hook it to the pcmcia card, can I)?

Given those db calculations, how do I compare the antenna options with
replacing my home 802.11b,g router with the 4X range $150 USD Linksys
802.11n WRT300N router and the required $120 USD Linksys WPC300N PCMCIA
card (assuming 6 db = 10^6/10)?Will this three-antenna 802.11n router be
forced to drop down to 1X speeds because inside my house my kid's laptops
will all be using 802.11b or 802.11g? Or can the router work on both
802.11g to one computer and on 802.11n to the other computer at the same
time?

I'm so confused!

All I want is to make a well-informed buying decision to increase my WiFi
range reliably to 300 feet to a known point.

Can you help me sort out all these very confusing variable (to me anyway)?
I have no training in electrical engineering; but I can google.

Thank you,
Beverly

"Beverly Erlebacher" wrote in message
.. .
Can you help me roughly CALCULATE how to increase the range of my
home
Internet wireless WiFi setup to a shed 300 feet away from my house?

Presently, I can walk about half the way through the wooded area to
the
shed with my laptop in hand before I lose the connection to the
PCMCIA
802.11b,g Linksys card. Basically I need to gain 150 feet in
"range".

But how?

At the store, I immediately become confused as I try to compare $30
USD
omnidirectional antennas (D-Link ANT24-070) that boost "power" by a
claimed
7 db; $50 USD directional corner antennas (Hawking HAI15SC) that
claim 15
dbi (whatever a dBi is); and $150 USD 802.11N routers that claim to
boost
omnidirectional "range" by 4x (Linksys WRT300N).

How does an omnidirectional 7 db or directional 15 dBi boost in
"power"
equate to range?

Approximately how many decibels of (omnidirectional or directional)
power
do I really need to boost my WiFi range from about 150 feet to the
300 feet
I need?

Looking up what a decibel is
(http://en.wikipedia.org/wiki/Decibel#Definition), I
calculate the D-Link ANT24-070 omnidirectional antenna gives me
about 5
times the power (assuming 7 db = 10^7/10 ~= 5); but does this get me
the
additional 150 feet of range to my shed?

Spending almost twice as much money on the Hawking HAI15SC
directional
antenna gets me roughly 30 times the power (assuming 15 db =
10^15/10 ~=
32); but is that enough power to get me the range to my shed?

Indeed, is there some way to add a Hawking 15db antenna on the
receiving
end to get 1,000 times the power (15 db + 15 db = 30 db = 10^30/10
~=
1,000); but what would I hook the wire output from this receiving
antenna
to in the shed (I can't hook it to the pcmcia card, can I)?

Given those db calculations, how do I compare the antenna options
with
replacing my home 802.11b,g router with the 4X range $150 USD
Linksys
802.11n WRT300N router and the required $120 USD Linksys WPC300N
PCMCIA
card (assuming 6 db = 10^6/10)?Will this three-antenna 802.11n
router be
forced to drop down to 1X speeds because inside my house my kid's
laptops
will all be using 802.11b or 802.11g? Or can the router work on both
802.11g to one computer and on 802.11n to the other computer at the
same
time?

I'm so confused!

All I want is to make a well-informed buying decision to increase my
WiFi
range reliably to 300 feet to a known point.

Can you help me sort out all these very confusing variable (to me
anyway)?
I have no training in electrical engineering; but I can google.

Thank you,
Beverly
==========================================

Very simply - four times the transmitter power ( +6 dB ) doubles the
range.

Is your receiver sufficiently sensitive? Or is the received signal
below the noise level?
----
Reg.

On Tue, 04 Jul 2006 06:28:16 -0000, Dave Platt wrote:
Can you help me roughly CALCULATE how to increase the range of my home
Internet wireless WiFi setup from 150 feet to a shed 300 feet away?

Doubling the range requires 6 dB of additional gain from the antennas
at one end or the other.

Hi Dave,

First thank you for taking the time to help me and anyone who read this.
Second, I'm going to have to go slowly with you so I'll respond one by one.

Third, does your statement that 6 dB of gain equates to 2 times the range
mean that the "square root" of the power difference is my key to
calculating the range?

That is, is this range calculation from dB power roughly true (based on
what you said)?

6 dB = 10^(6/10) ~= 4X the power, where the square root of 4X equals a
doubling the range (assuming an omnidirectional antenna)?

Beverly

6 dB = 10^(6/10) ~= 4X the power, where the square root of 4X equals a
doubling the range (assuming an omnidirectional antenna)?

I'm hoping I can extrapolate from the above statement to calculate the dB
gain for the $150 Linksys WRT300N router which claims a 4X range
improvement (so I can compare the $50 antenna's effect with that of the
802.11n router).

Following your lead, the power improvement necessary for a 4X range
improvement is 4^2 = 16X power gain.

This 16X power gain then equates to about 12 dB (since 12 dB = 10^[12/10]
~= 16X power).

So, is it safe to calculate that the claimed 4X range improvement of the
Linksys WRT300N wireless broadband router can be compared to that of a 12
dB gain omnidirectional antenna?

Beverly

On Tue, 04 Jul 2006 06:28:16 -0000, Dave Platt wrote:
Can you help me roughly CALCULATE how to increase the range of my home
Internet wireless WiFi setup to a shed 300 feet away from my house?

dBi refers to gain relative to an "isotropic" antenna
dBd refers to gain relative to a half-wave dipole
dBi numbers are approximately 2 dB higher than dBd numbers,
for the same actual amount of gain.

Hi Dave,

Oh my. I guess the Hawking marketing folks were trying to trick me by
quoting a decibel number that was higher those I compared with.
15 dBi ~= 15 -2 ~= 13 dBd

That makes the $50 USD 15 dBi Hawking HAI15SC Hi_Gain Antenna drop down
from a gain of 32X power to only 20X power which gives me about a 4X range.

13 dBd = 10^(13/10) power ~= 20x power

Assuming the square of the power is the range, I get 4X range.
20^(1/2) ~= 4X range

Assuming my reliable range is 100 feet, that equates to 400 feet of range.
100 feet * 4 = 400 feet range

Interestingly, for comparison purposes, that is the SAME RANGE that the
much more expensive Linksys (Cisco) WRT300N router claims.

Do these calculations make sense?
Beverly

On Tue, 04 Jul 2006 06:28:16 -0000, Dave Platt wrote:
Can you help me roughly CALCULATE how to increase the range of my home
Internet wireless WiFi setup to a shed 300 feet away from my house?

3 dB of additional gain equates to twice the delivered power at a
specific range. Because power falls off in proportion to the square
of the distance, twice the power yields sqrt(2) or about 1.4 times the
range, all else being equal (which it often isn't).

6 dB of additional gain is four times the delivered power at a given
distance, or twice the range for the same amount of power.

So that I may compare the different options available at the store to me
for increasing my range, are these simplified calculations below correct?

a. 3 dBd additional gain = 10^(3/10) ~= 2x the delivered power
b. 2x power = 2^(1/2) effective range ~= 1.4X the range

b. 6 dBd additional gain = 10^(6/10) ~= 4x the delivered power
b. 4x power = 4^(1/2) effective range ~= 2X the range

Can someone let me know if these calculations are correct because that
helps me equate the different antennas and routers to the one measure I
desire, which is effective range in the area of 400 feet.

Beverly

On Tue, 04 Jul 2006 06:28:16 -0000, Dave Platt wrote:
Approximately how many decibels of (omnidirectional or directional)
power do I really need to boost my WiFi range from about 150 feet
to the 300 feet I need?

The _minimum_ you appear to need is 6 dB of additional gain. I'd
recommend trying for 10 dB or more in order to ensure a reliable
connection.

May I ask WHERE that 6 dBd of gain is coming from?

Is it ONLY from the "better" antenna?

If that additional 6 dBd is coming from a "better" antenna, then why didn't
they put that better antenna on my router in the first place?

Since the antenna isn't "powerered", there is no external amplifier .... so
I am a bit confused as to WHERE that power is coming from?

Can you unconfusify me here?
Beverly

On Tue, 04 Jul 2006 06:28:16 -0000, Dave Platt wrote:
It's possible to fabricate a corner reflector, or (even better) a
parabolic reflector, out of material as inexpensive as cardboard
(or posterboard or something like that) lined with aluminum foil.

Hmm. At first, I thought you were pulling my leg; but a simple google for
more details gave me more homemade WiFi antenna reading than I can handle
in a month. Whew. Here, for others to share, are the Yagi pringles can
antennas (aka cantenna) which purport to "refocus" the WiFi signal from my
router in my house to my shed 300 feet away.

http://en.wikipedia.org/wiki/Cantenna
http://www.oreillynet.com/cs/weblog/view/wlg/448
http://www.seattlewireless.net/index...inglesCantenna
http://www.wi-fiplanet.com/reviews/article.php/3401501
http://www.turnpoint.net/wireless/has.html
http://www.binarywolf.com/249/pringles_cantenna.htm
http://verma.sfsu.edu/users/wireless/pringles.php
http://www.seattlewireless.net/index.cgi/CookieCantenna
http://webserver.computoredge.com/ed...2339/cover.htm
http://www.signonsandiego.com/news/c...b13canned.html
http://www.overclock.net/faqs/17669-...l-booster.html
http://www.g4tv.com/screensavers/fea...i_Antenna.html
http://www.netscum.com/~clapp/wireless.html
http://www.flickr.com/photos/binarywolf/sets/837698/
http://linuxathome.com/files_images/cantenna.pdf

Given that there are two fundamental design styles:
a) Parabola
b) Tube

Do folks here recommend the pringles cantenna or the pie tin antenna for my
2-antenna router 802.11b,g directional application where I need to also
feed the computers within the house in addition to the shed 300 feet away?

Beverly

On Tue, 04 Jul 2006 05:50:02 -0400, Rôgêr wrote:
Do folks here recommend the pringles cantenna or the pie tin antenna for my
2-antenna router 802.11b,g directional application where I need to also
feed the computers within the house in addition to the shed 300 feet away?

I use panel antennas almost exclusively, exceptions being some 24dbi
mesh antennas for backhaul.

Hi Rôgêr,

After reading all the articles posted, I now understand that:

a) The pringles can is hip; but it's the worst performer
http://www.oreillynet.com/cs/weblog/view/wlg/448
(it's not even metal foil lined and it's too small in diameter)

b) The coffee cantenna is more effective than the pringles cantenna
http://www.oreillynet.com/cs/user/view/wlg/1124

c) The dish antenna is the simplest of all and almost as good
http://www.freeantennas.com/projects/template
http://www.freeantennas.com/projects...te2/index.html

I also see, as Rod Speed so kindly noted, that the give and take is that we
lose range in some directions in favor of range in the desired direction.
Fair enough.

My one question is a practical one.

Why are there two antennas on my router anyway? Is one transmit and the
other receive? Or are they both transmit and receive?

Given I have TWO omnidirectional antennas on my wireless router, if I put
the parabolic dish antenna on one to direct it to my shed, does that allow
the OTHER antenna to radiate around the house to handle the other computers
roving around the house?

Beverly

Beverly Erlebacher wrote:
Can you help me roughly CALCULATE how to increase the range of my home
Internet wireless WiFi setup to a shed 300 feet away from my house?

Presently, I can walk about half the way through the wooded area to the
shed with my laptop in hand before I lose the connection to the PCMCIA
802.11b,g Linksys card. Basically I need to gain 150 feet in "range".

But how?
====================================
Having followed today's postings on this topic , I see that there is a
wooded area between your house and shed, hence there seems to be no free
line of sight between the house and the shed.
That's why it is difficult to calculate/predict the Gain you need to
penetrate the wooded area with a 2.4 GHz signal.

If you wish to use the laptop inside the shed at a fixed location it
MIGHT be good enough if you install (for example)a corner reflector yagi
(High Gain)antenna at both the house AND the shed. However then your
laptop needs a plug-in PCMCIA WiFi tansceiver with a connection for an
external antenna.
One of such units is the Make: Buffalo - Air Station Turbo G ,High Power
-unit which also has a built-in antenna.
Note : The coaxial cable between the 2 devices and their associated
antenna should be limited to only a few metres because of the high
frequency being 2.4GHz

Communication here is 2 way . Your laptop might receive the ( antenna
amplified) signal from your router located in the house ,but that does
not mean the router will receive the signal from the laptop without
additional facilities at the laptop.

Again , because of the probably partly obstructed path (wooded area) it
is difficult making any sensible calculations.

Frank GM0CSZ / KN6WH