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Using powerline to get wireless past a "thick" kitchen wall

Last response: in Wireless Networking
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December 19, 2004 12:32:16 PM

Archived from groups: alt.internet.wireless (More info?)

Currently I use a wireless router (WRT54GS) to share cable internet
access. The wireless signal from the router has to make it past the
kitchen to 3 wireless computers. The 3 computers could barely connect
and there were many lost packets. I determined there was a dramatic drop
in signal strength (10's of dB's) just going through the kitchen
cabinets (hardwood cabs filled with all sorts of stuff). Plus there's a
big refrigerator in the way.

I added a repeater (WAP54G in repeater mode). My "thick" kitchen wall is
inbetween the WRT and WAP. The results are much better. The 3 computers
connect to the WAP at 54Mbps very reliably.

However, the overall file transfer speeds from WRT to WAP to wireless
computers are only about 2-3 Mbps. I suspect the link between WRT and
WAP suffers from the thick kitchen wall. I want to improve the speed of
this link.

Would a powerline network help in this case? I'm thinking of using two
powerline bridges (Linksys PLEBR10) like this:

WRT > PL#1 > (kitchen wall here) > PL#2 > WAP

Thanks for any comments,

Lance
*****
Anonymous
a b F Wireless
December 19, 2004 2:25:37 PM

Archived from groups: alt.internet.wireless (More info?)

On Sun, 19 Dec 2004 09:32:16 -0800, Lance <lltbhill@link_earth.net>
wrote:

>Currently I use a wireless router (WRT54GS) to share cable internet
>access. The wireless signal from the router has to make it past the
>kitchen to 3 wireless computers. The 3 computers could barely connect
>and there were many lost packets. I determined there was a dramatic drop
>in signal strength (10's of dB's) just going through the kitchen
>cabinets (hardwood cabs filled with all sorts of stuff). Plus there's a
>big refrigerator in the way.

Drill a hole in the wall. Attach a coax cable to one of the antenna
ports on the WRT54GS, pass it through the hole, and connect an antenna
(I suggest a $30 8dBi patch antenna). Don't run it through an
electrical wall outlet box.

>I added a repeater (WAP54G in repeater mode). My "thick" kitchen wall is
>inbetween the WRT and WAP. The results are much better. The 3 computers
>connect to the WAP at 54Mbps very reliably.
>
>However, the overall file transfer speeds from WRT to WAP to wireless
>computers are only about 2-3 Mbps. I suspect the link between WRT and
>WAP suffers from the thick kitchen wall. I want to improve the speed of
>this link.

Two problems:
1. Repeaters and WDS cut your thruput in half (or worse). Since they
are half-duplex devices, they can only transmit and receive one at a
time.
2. Thruput is totally dependent on connection speed. You're NOT
going to get a 54Mbit/sec connection going through a thick wall and a
repeater. There's not enough S/N ratio to do it, and you'll get lots
of reflections to screw up the works. My guess(tm) is that you'll get
about a 12Mbit/sec connection on both the WRT54GS and the WAP54G
repeater, resulting in 6Mbits/sec thruput between boxes, and at best
3Mbits/sec from end to end.

>Would a powerline network help in this case? I'm thinking of using two
>powerline bridges (Linksys PLEBR10) like this:
>
>WRT > PL#1 > (kitchen wall here) > PL#2 > WAP

I've had thruput problems with power line network devices (HomePNA)
when used as a bridge.
http://www.homeplugs.net
I haven't played with it for a while, but a few years ago, the best I
could do was about 5Mbits/sec thruput. There are claims of
14Mbits/sec on current products, but I have no experience. Try the
various review sites.

If you decide to go this route, you will have the same half-duplex
problem as with the repeater. HomePNA is half duplex and therefore
cuts your bandwidth in half. If you use it as an extension cord for
your WAP54G, you will lose bandwidth.

Since you already have a WAP54G, just drill a hole in the wall, run
CAT5 through the hole, and connect the WAP54G as an access point.
Pick a different channel (1, 6, 11) so as not to interfere with your
WRT54GS but use the same SSID and encryption key. If drilling the
hole is a problem, see if you can borrow some telephone pairs. You
can run 10baseT over telco wire for short distances between switched
ports.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
Anonymous
a b F Wireless
December 19, 2004 2:38:56 PM

Archived from groups: alt.internet.wireless (More info?)

On Sun, 19 Dec 2004 11:25:37 -0800, Jeff Liebermann
<jeffl@comix.santa-cruz.ca.us> wrote:

>If you decide to go this route, you will have the same half-duplex
>problem as with the repeater. HomePNA is half duplex and therefore
>cuts your bandwidth in half. If you use it as an extension cord for
>your WAP54G, you will lose bandwidth.

Oops. That was wrong. Since it doesn't share the same communications
medium with wireless, HomePNA power line networking does NOT cut the
thruput in half.

[My proof reader doesn't work on weekends.]


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
December 20, 2004 12:19:12 PM

Archived from groups: alt.internet.wireless (More info?)

Jeff Liebermann said the following on 12/19/2004 11:38 AM:
> On Sun, 19 Dec 2004 11:25:37 -0800, Jeff Liebermann
> <jeffl@comix.santa-cruz.ca.us> wrote:
>
>
>>If you decide to go this route, you will have the same half-duplex
>>problem as with the repeater. HomePNA is half duplex and therefore
>>cuts your bandwidth in half. If you use it as an extension cord for
>>your WAP54G, you will lose bandwidth.
>
>
> Oops. That was wrong. Since it doesn't share the same communications
> medium with wireless, HomePNA power line networking does NOT cut the
> thruput in half.
>
> [My proof reader doesn't work on weekends.]

Thanks very much for your comments Jeff. I may just have to get off my
duff and run some cable under the kitchen to the other side. I'll then
put the WAP45G into access point mode instead of repeater mode.

Plus, since I'll be crawling around under the house anyway, I can get my
wife's computer wired up too.

Lance
*****
!