WiFi Cabling - dB loss per foot

The antenna on my network card needs to be sitting in my window to
access a public AP. This is very inconvenient. I was thinking about
getting an extending cable for my antenna, about 15 feet long, but
from what I understand there is extreme signal loss per foot when
dealing with WiFi cables. I forget the math but it's around 5dB of
loss for 15 feet, which is pointless if your going to use a 5dB
antenna.

So I'm thinking of using something like this, as it uses a USB cable
to cover the distance:
http://www.newegg.com/Product/Produc...82E16833168023

My question(s) are: Will I experience the same extreme dB loss using
this on a 15 foot USB cable instead of a 15 foot WiFi cable with an
antenna at the end? Is the USB signal amplified somehow? How do people
who put antennas on their roof and connect them to a computer in their
basement deal with signal loss on the 20-30 foot cable? etc etc

(other solutions/links are welcomed)

Thanks in Advance Guys

On Oct 9, 8:56*am, Dennis <dennispub...@hotmail.com> wrote:
> The antenna on my network card needs to be sitting in my window to
> access a public AP. This is very inconvenient. I was thinking about
> getting an extending cable for my antenna, about 15 feet long, but
> from what I understand there is extreme signal loss per foot when
> dealing with WiFi cables. I forget the math but it's around 5dB of
> loss for 15 feet, which is pointless if your going to use a 5dB
> antenna.
>
> So I'm thinking of using something like this, as it uses a USB cable
> to cover the distance:http://www.newegg.com/Product/Produc...82E16833168023
>
> My question(s) are: Will I experience the same extreme dB loss using
> this on a 15 foot USB cable instead of a 15 foot WiFi cable with an
> antenna at the end? Is the USB signal amplified somehow? How do people
> who put antennas on their roof and connect them to a computer in their
> basement deal with signal loss on the 20-30 foot cable? etc etc
>
> (other solutions/links are welcomed)
>
> Thanks in Advance Guys

There is no RF loss with USB. You might want to consider a moderate
gain directional antenna of you are going to put this by the window.

I think the general consensus is high power doesn't buy you all that
much unless you have high power on both sides (host and client). So
you don't need this particular unit. The newegg review complaining
about mobo problems may have a usb power issue, especially in the case
where it connects then drops.

USB is one good way to go. Another USB adapter to consider at
NewEgg:
http://www.newegg.com/Product/Produc...82E16833315075

Removable antenna is smart. That way you can always upgrade if you
need a better connection.


Also, you might consider an ethernet bridge adapter. These will
connect to your computer using ethernet cable, which has a theoretical
limit of 100 meters! Zero loss.

Here's a cheap one: http://www.newegg.com/Product/Produc...82E16817201523

It's called AP, but does more- under features:
"Provides station mode to act as a wireless LAN client station"

Dennis wrote:
> The antenna on my network card needs to be sitting in my window to
> access a public AP.

You might want to look at the Ubiquiti Nanostation 2 for $79.

http://ubnt.com/products/ns2.php

On Oct 10, 7:09*am, seaweedsl <seaweedst...@gmail.com> wrote:
> USB is one good way to go. *Another USB adapter to consider at
> NewEgg:http://www.newegg.com/Product/Produc...82E16833315075
>
> Removable antenna is smart. *That way you can always upgrade if you
> need a better connection.
>
> Also, you might consider an ethernet bridge adapter. *These will
> connect to your computer using ethernet cable, which has a theoretical
> limit of 100 meters! * *Zero loss.
>
> Here's a cheap one:http://www.newegg.com/Product/Produc...82E16817201523
>
> It's called AP, but does more- *under features:
> "Provides station mode to act as a wireless LAN client station"

Not a bad idea, though it require a wall wart, while the USB device is
powered via the cable. My experience is USB is more likely to have a
driver problem than ethernet. I think any ethernet device other than a
card on the bus doesn't need a driver.

On Oct 10, 11:35*am, DTC <DTC_no_s...@example.com> wrote:
> Dennis wrote:
> > The antenna on my network card needs to be sitting in my window to
> > access a public AP.
>
> You might want to look at the Ubiquiti Nanostation 2 for $79.
>
> http://ubnt.com/products/ns2.php

Great info thanks guys!

The Nanostation looks very interesting, I'm tempted... but it uses
power over ethernet so I'll need a PoE network card or adapter? Is
this it? http://www.newegg.com/Product/Produc...82E16833127059

Also I'm a bit confused about what makes it a good antenna. The main
number I've been focused on is the tx/rx dB, the webpage says the
Nanostation says it's "10dB x 2"? In reality what's that mean? 20 dB?
I've been looking at some of the homemade antennas on YouTube... some
claim to be around 12dB etc etc ... how does a commercial antenna like
this compare; what other numbers factor into it?

You are on the right track using a USB wireless adapter and usb
extensions (if necessary) to your computer. Low loss coaxial cable is
expensive, and still loses too much of the signal to be worth the
trouble. There are a couple of higher power (500 mw) wireless
adapters on the market, but you should do fine with a good USB device
in the window, running a cable to one of the ports on your computer.
Consider using a powered hub if you need to run more than 2 meters of
USB cable. It works! You can use an adapter in a top-floor window
and pass USB data to your basement this way...

Take a look at the wi-fi antennas page: http://www.ab9il.net/wlan-projects/wifi1.html
for some home-build ideas. A bit of gain can greatly extend your
range / data rate.

Good Luck
Phil

http://www.ab9il.net

Dennis wrote:

> The antenna on my network card needs to be sitting in my window to
> access a public AP. This is very inconvenient. I was thinking about
> getting an extending cable for my antenna, about 15 feet long, but
> from what I understand there is extreme signal loss per foot when
> dealing with WiFi cables. I forget the math but it's around 5dB of
> loss for 15 feet, which is pointless if your going to use a 5dB
> antenna.
>
> So I'm thinking of using something like this, as it uses a USB cable
> to cover the distance:
> http://www.newegg.com/Product/Produc...82E16833168023
>
> My question(s) are: Will I experience the same extreme dB loss using
> this on a 15 foot USB cable instead of a 15 foot WiFi cable with an
> antenna at the end? Is the USB signal amplified somehow? How do people
> who put antennas on their roof and connect them to a computer in their
> basement deal with signal loss on the 20-30 foot cable? etc etc
>
> (other solutions/links are welcomed)
>
> Thanks in Advance Guys

An AP in client mode would do it if there is an AC plug nearby.
Most APs can be run in several modes and only need a CAT 5 or 6 cable and
are OS independent.

D-Link's DWL-G730AP is a good example...

Couple more comments to help clarify your options:

USB: If you have USB 2.0, then you should not need a USB hub until
you are over 15 feet. So, USB should work well buying nothing more
than the USB adapter and a 15' extension. This has been my experience
with a couple different USB adapters.

Ethernet: What DTC is saying is that you will not need anything extra
with the Nanostation to use it. If I understand correctly (have not
used it) the Nano comes with an injector that you plug the ethernet
cable into and then it adds power for the nano for the cable that
comes out of it. So you will need two ethernet cables; laptop to
injector, then injector to Nanostation. (DTC; please correct me if
I'm wrong, guys)

For the cheaper AP/client adapters, you will have to plug in it's wall
wart power supply directly to the back of the adapter. From what I
can tell, this is not an issue if it is to be used indoors on your
windowsill. POE seems to make sense for installations that are
outdoors or more than 10-20 feet from a wall plug perhaps.

Antennas. If you are getting acceptable connections at the window
with your adapter card and antenna, then whatever antenna that comes
stock with your adapter should be fine. I really doubt that you need
even a 10dbi antenna, not to mention something more powerful. Probably
a simple 2 dbi omni antenna (could add a reflector) is fine,
considering what you have reported so far.

What is the gain on your current working setup's antenna? Is it a
adecuate connection when at the window ?

Cables: There are antenna cables that are lower loss. The LMR400
cable (about 1/2" thick) loses .25 db per meter at 2.4 Ghz. So a 3
meter cable would lose .75 db. Call it 1 db with connector loss. But
these are thick and expensive and will require pigtail adapters to be
flexible enough to use. Do-able, but not practical.

Steve

seaweedsl wrote:
> Ethernet: What DTC is saying is that you will not need anything extra
> with the Nanostation to use it. If I understand correctly (have not
> used it) the Nano comes with an injector that you plug the ethernet
> cable into and then it adds power for the nano for the cable that
> comes out of it. So you will need two ethernet cables; laptop to
> injector, then injector to Nanostation. (DTC; please correct me if
> I'm wrong, guys)

That's correct...you need two cables. The NS is auto-sensing, so it can
be a crossover or straight cable. If your hub or switch has 49 volt PoE,
it won;t pass through the NS's power injector. You just can't plug the
NS directly into the 48 volt hub.