850 foot wireless bridge design

I would like to create a bridge between our house and a recreational
cabin we have on the farm in order to have internet service at the
cabin. I presently have a D-Link Di624 wireless router connected to the
satellite modem. This is situated about 5 feet from a window which has
clear line of site to a cabin window 850 feet away. All I need in the
cabin is wireless internet. I presently have computers and printer
connected to the DI624 and a wireless notebook.

I am considering a WAP54G at each end of the bridge with (2) Ez12 12dB
antennas from www.freeantennas.com on each.

1. Is there a better approach?
2. Assuming the Ez12's will block the signal in the cabin, what is the
best remedy for this?
3. Are the rubber duckies good enough or will it require the 7dB high
gain antennas?
4. What about signal conflicts between the DI624 and WAP54G in the
house?

I am basically looking for experienced help in designing the best (ie
most economical) system to add the internet access at the cabin.
Retaining the DI624 is not a must. I do need to retain the wired
network and wireless access in the house.

The satellite modem has to have ip address 192.168.0.1
The WAP's will be sitting at the windows.

I've researched the group and learned a lot, but I'd appreciate a
little expert help.

Thanks in advance,
Ken


House
------------------------------------------------------
| wireless notebook |
| |
| -------- |
| satellite | |----- |
| modem -----| D-Link |----- |
| | | DI-624 |----- cat5 to other rooms |
| 5 ft. | | |
| | -------- |
--|window|--------------------------------------------
|
850 ft.
| Cabin
--|window|------------------
| |
| |
| |
| |
| |
| wireless notebook |
----------------------------

Sorry, my sketch didn't come thru too well.
Ken

(E-Mail Removed) wrote:
> I would like to create a bridge between our house and a recreational
> cabin we have on the farm in order to have internet service at the
> cabin. I presently have a D-Link Di624 wireless router connected to the
> satellite modem. This is situated about 5 feet from a window which has
> clear line of site to a cabin window 850 feet away. All I need in the
> cabin is wireless internet. I presently have computers and printer
> connected to the DI624 and a wireless notebook.
>
> I am considering a WAP54G at each end of the bridge with (2) Ez12 12dB
> antennas from www.freeantennas.com on each.
>
> 1. Is there a better approach?
> 2. Assuming the Ez12's will block the signal in the cabin, what is the
> best remedy for this?
> 3. Are the rubber duckies good enough or will it require the 7dB high
> gain antennas?
> 4. What about signal conflicts between the DI624 and WAP54G in the
> house?
>
> I am basically looking for experienced help in designing the best (ie
> most economical) system to add the internet access at the cabin.
> Retaining the DI624 is not a must. I do need to retain the wired
> network and wireless access in the house.
>
> The satellite modem has to have ip address 192.168.0.1
> The WAP's will be sitting at the windows.
>
> I've researched the group and learned a lot, but I'd appreciate a
> little expert help.
>
> Thanks in advance,
> Ken
>
I have set up quite a few low cost systems like this for farmers.
Assuming no other problems such as interference, parking machinery in
the line of site etc, since it is a do it yourself job, I would start
small and work my way up. You could use a couple of WAP54G's one as
access point and the other one at the far end as a repeater and see what
happens.

From past experience, at that distance you will probably need to use
one of the 12dbi antennas at the main farm house mounted externally, and
the repeater in the window at the other end.

If the connection isn't reliable then add the other 12dbi at the remote
end. Sometimes you can get enough signal off of the external antenna to
be functional inside the building. If you can't get enough signal
inside, then you might want to set them up as a point to point bridge
and add a third access point or router inside.

Some people have reported issues with the WAP54G but so far I haven't
had any and have found them to be quite reliable - touch wood.

As an alternative to the WAP54G you could use WRT54GL routers running
DD-WRT.

A couple of things to remember - as far as I know the WAP54G can only
serve as a repeater using WEP. In point to point mode you can use WPA.
The people in the other house will be on your network.

If you need to keep them off your network I would place a WRT54GL router
running DD-WRT in front of your existing router and use WDS to connect
it to another WRT54GL running DD-WRT sitting in the remote window. In
this setup you can use WPA.

I haven't tried the 7dbi antennas before.

Selecting different channels (use 1, 6 or 11) and you shouldn't have a
problem with your existing setup.

Ian

Ian <(E-Mail Removed)> hath wroth:

>Some people have reported issues with the WAP54G but so far I haven't
>had any and have found them to be quite reliable - touch wood.

I've had erratic hang problems with WAP54G v3.1 firmware v3.04 in
bridge mode. It does not hang in access point and access point client
mode.

>As an alternative to the WAP54G you could use WRT54GL routers running
>DD-WRT.

Yep. Recommended. However, I prefer Buffalo WHR-HP-G54.

>A couple of things to remember - as far as I know the WAP54G can only
>serve as a repeater using WEP. In point to point mode you can use WPA.
>The people in the other house will be on your network.

Not so. The WAP54G in repeater mode will work with WPA-PSK. See
release notes for v2.08 at:
<http://www.linksys.com/servlet/Satellite?blobcol=urldata&blobheadername1=Content-Type&blobheadername2=Content-Disposition&blobheadervalue1=text%2Fplain&blobhead ervalue2=inline%3B+filename%3Dwap54g_fw_ver304.txt &blobkey=id&blobtable=MungoBlobs&blobwhere=1130826 433584&ssbinary=true>
However, in bridge mode, only WEP is supported. Strangely, it will
let you configure WPA-PSK, but it will not connect.

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

(E-Mail Removed) hath wroth:

>I would like to create a bridge between our house and a recreational
>cabin we have on the farm in order to have internet service at the
>cabin. I presently have a D-Link Di624 wireless router connected to the
>satellite modem. This is situated about 5 feet from a window which has
>clear line of site to a cabin window 850 feet away. All I need in the
>cabin is wireless internet. I presently have computers and printer
>connected to the DI624 and a wireless notebook.
>
>I am considering a WAP54G at each end of the bridge with (2) Ez12 12dB
>antennas from www.freeantennas.com on each.
>
>1. Is there a better approach?

Yes. Put the DI-624 wireless in the window, not the modem. The
wireless needs the line of sight to the cabin, not the modem.

>2. Assuming the Ez12's will block the signal in the cabin, what is the
>best remedy for this?

Not easily. It might be possible to install a power splitter at the
DI-624 sending half the power to a directional antenna pointed at the
cabin and the other half throughout the house.

>3. Are the rubber duckies good enough or will it require the 7dB high
>gain antennas?

See calculations below.

>4. What about signal conflicts between the DI624 and WAP54G in the
>house?

What WAP54G? In the cabin?

>I am basically looking for experienced help in designing the best (ie
>most economical) system to add the internet access at the cabin.
>Retaining the DI624 is not a must.

A WDS repeater will probably be the cheapest.

>I do need to retain the wired
>network and wireless access in the house.

So, everything is moving to the cabin? Could you describe where the
computers are located and how they are intended to connect when you're
done with the system, not in its current arrangement?

Ok, lets grind the numbers. I've only done this about 20 times in
this newsgroup, but once more won't hurt (much):

See examples in the Wireless FAQ at:
<http://wireless.wikia.com/wiki/Wi-Fi#Link_Calculations>

From what we know so far, we have 850ft range, unknown antennas,
conventional radios, and are looking for at least a 20dB fade margin.
I'll assume 12Mbits/sec connection speed for 6 Mbits/sec thruput.

TX power = +15 dBm
TX coax loss = 2dB (to window mounted antenna)
TX antenna gain = unknown
Distance = 0.16 miles (850ft)
Rx antenna gain = unknown
RX coax loss = 2dB (to windows mounted antenna)
RX sens = -84 dBm (at 12 Mbits/sec)
Fade margin = 20 dB

Plugging into:
<http://www.terabeam.com/support/calculations/som.php>
and trying various values of antenna gain until I get 20dB fade
margin, I get antenna gains of 7dBi each for both antennas. If you
have line of sight, and a clear Fresnel zone, a pair of rubber ducky
gain antennas should work. The total gain of 14dBi can be distributed
unequally. For example, the stock 2dBi omni can be used on one end,
with a 12dBi directional panel on the other end.

Expect reflection problems if you're shooting through a window frame.

For 850ft the Fresnel Zone radius clearance at midpoint:
<http://www.terabeam.com/support/calculations/fresnel-zone.php>
must be 7.4ft. That means your antennas must be 7.4ft off the ground
for this to work reliably. This may be a problem with your
topography.

Change the numbers to match your speed requirements or antenna
configuration that affect coax loss and antenna gain.

For a radio at the cabin end, you can use just about any of the
wireless client bridge radios listed at:
<http://wireless.wikia.com/wiki/Wi-Fi#Wireless_Ethernet_Bridges>
that support a client mode. Not all do so please check first. I
would be tempted to use a "universal" solution, such as Buffalo
WHR-HP-G54, which can be configured as a client bridge or WDS bridge.

The problem with using just a wireless client bridge is that you
cannot connect to it via wireless from your notebook. In order to do
that, you'll need to build a WDS (wireless distribution system)
bridge. WDS allows the device to simultaneously act as a repeater and
an access point. Replace the DI-624 in the house with a router that
supports WDS and add an identical router in the cabin. You can
connect to the one on the cabin with either wired or wireless.

The catch is that you will see a 50% minimum slowdown for the wireless
laptop connection, but the wired connection will run at full speed.
Also, WDS setup is often a bit challenging:
<http://www.dd-wrt.com/wiki/index.php?title=WDS_Linked_router_network>
<http://www.wi-fiplanet.com/tutorials/article.php/3628576> (2 pages)

--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

> (E-Mail Removed) wrote:
>> I would like to create a bridge between our house and a recreational
>> cabin we have on the farm in order to have internet service at the
>> cabin. I presently have a D-Link Di624 wireless router connected to
>> the satellite modem. This is situated about 5 feet from a window
>> which has clear line of site to a cabin window 850 feet away. All I
>> need in the cabin is wireless internet. I presently have computers
>> and printer connected to the DI624 and a wireless notebook.
>>
>> I am considering a WAP54G at each end of the bridge with (2) Ez12
>> 12dB antennas from www.freeantennas.com on each.
>>
>> 1. Is there a better approach?
>> 2. Assuming the Ez12's will block the signal in the cabin, what is
>> the best remedy for this?
>> 3. Are the rubber duckies good enough or will it require the 7dB high
>> gain antennas?
>> 4. What about signal conflicts between the DI624 and WAP54G in the
>> house?
>>
>> I am basically looking for experienced help in designing the best (ie
>> most economical) system to add the internet access at the cabin.
>> Retaining the DI624 is not a must. I do need to retain the wired
>> network and wireless access in the house.
>>
>> The satellite modem has to have ip address 192.168.0.1
>> The WAP's will be sitting at the windows.
>>
>> I've researched the group and learned a lot, but I'd appreciate a
>> little expert help.
>>
>> Thanks in advance,
>> Ken
>>

Depends.. How do you have power to the cabin? At my place in North Idaho, I
had the sat/wireless/wired in the house, and wanted wireless back at the
outbuilding (about 1000 ft from the main house), however, we had power from
the house to the outbuilding, and found powerline networking to be much more
reliable (winter precipitation, summer growth from the bushes/trees)..

Netgear makes two types of devices, one is a powerline bridge for wired
stuff, and the other is a bridge to a remote AP (plug on in inside, the
other in the outbuilding).. See the info at
http://www.netgear.com/Products/Powe...g.aspx?for=All usually
around $99-$130 for both parts... (that's for the 54Mbps devices, same speed
as wireless).. While they do make 200 Mbps devices, those are for Gigabit
ethernet, Not the usual 100 Mbps stuff in most homes

If you have a wap/router in the house, just use a cat5(or cat 6) cable to go
from the router part, to the input of one of the powerline devices, second
part plugs in and either has a wired connection/or a wireless ap (comes as
ssid NETGEAR)

Wish I had power run to the cabin. That would be a nice approach.
At present, we only have generator power. I've thought I could probably
power the network equipment at the cabin with 12 volt batteries if we
don't want to run the generator. Seems like most of the equipment I've
looked at is </= 12 vdc.

Ken

Ian,
Thanks for your help. I am going to take a look at recommendations from
you and Jeff. I'll probably have more questions then.
Ken

Jeff,
It will take me a little time to digest all this and look at the
equipment mentioned.. Here is more info on the existing system at the
house which will continue as is after addition of the cabin internet
service:

House:
Satellite modem --- DI624 wireless router --- ethernet computers &
ethernet printer + wireless notebook.

The cabin only needs wireless internet capabilities for one or two
notebooks. The cabin doesn't need to share the house network for file
sharing, etc.

I think I can get the 7.4 ft. antenna clearance above the ground at
both windows. Between buildings the ground drops away considerably
more. Transmission angle thru the windows will be approx 45°+/-.

As I mentioned, The DI624 can be replaced in the interest of a
better/cleaner system if necessary.
Thanks,
Ken

(E-Mail Removed) wrote:
> Wish I had power run to the cabin. That would be a nice approach.
> At present, we only have generator power. I've thought I could
> probably power the network equipment at the cabin with 12 volt
> batteries if we don't want to run the generator. Seems like most of
> the equipment I've looked at is </= 12 vdc.
>
> Ken

Lots of stuff for 12v (check the trucking and RV'ng newsgroups), however,
what sort of bushes/trees/etc are in the line of sight at your intended
place... We ended up doing the ditch/power/powerline networking, cuz in the
spring all sorts of stuff grew, and green leafy stuff atentuates a WiFi
signal BIG time.... Line of sight was fine in the winter, but during the
spring and summer, forgetaboutit... too much green stuff grew in the way..

Just an aside, our cabin/guest house, was about 1000 ft back on our acreage
(in the forest area).. We just bit the bullet and ran a direct burial AC
cable to the outbuilding (was about $600 for the cable, and $180 to rent the
"ditch witch" to dig the ditch)... A bit more than we intended to spend,
but figured we may as well kill two birds with one stone... (actually 3.. we
also buried a 20 conductor utility cable in the ditch while we were at it,
use it for phone/intercom/etc, was another $180 bucks.. Direct burial
electric cables only have to be about 2ft down (perfect for a ditch witch,
it only makes a 2 ft deep trench), it's water and sewer that has to be
buried about 4ft down ((or at least below the frost line for your area, and
sewer has to be angled/graded))).