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LinkSys WRT54GS and Power Over Ethernet

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Anonymous
October 11, 2004 4:07:38 PM

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

Hi,
I am going to buy a couple of LinkSys WRT54GS wireless routers to set up
an external wi-fi bridge (about 340 meters).

I will put the LinkSys routers on the roofs of the two houses and I want
to bring them the electrical power with the ethernet cable (power over
ethernet).

How can I do that?
Is there any kit I can buy?

I have another quick question: is the LinkSys power adapter
multi-standard (110 to 230 V)?

Thanks a lot.
October 11, 2004 4:07:39 PM

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

meATprivacyDOTnet thought carefully and wrote on 10/11/2004 3:07 AM:
<snip>
> I have another quick question: is the LinkSys power adapter
> multi-standard (110 to 230 V)?

Can't answer your other questions about the WRT54GS, but my WRT54GS
plug-in type transformer/power supply is single input only.

Input - 120VAC, 60Hz, 23W.
Output - 12VDC, 1000mA.

Lance
*****
Anonymous
October 11, 2004 4:07:39 PM

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

On Mon, 11 Oct 2004 12:07:38 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>I am going to buy a couple of LinkSys WRT54GS wireless routers to set up
>an external wi-fi bridge (about 340 meters).

I don't thin the WRT54GS will play transparent bridge. Methinks the
WAP54G is what you probably want. If you only want to bridge one
computah, then the WRT54GS at one end, and just about anything on the
other end, will work.

>I will put the LinkSys routers on the roofs of the two houses and I want
>to bring them the electrical power with the ethernet cable (power over
>ethernet).
>
>How can I do that?
>Is there any kit I can buy?

Linksys WAPPOE
http://www.linksys.com/products/product.asp?prid=582&sc...
Note the list of supported products. I find it interesting that the
WRT54G is supported. The WAPPOE box outputs 5VDC while the Linksys
WRT54G allegedly runs on 12VDC. Well the answer is that the WRT54G
will run on just about anything between 5VDC and about 18VDC. That's
because internally, it runs on 3.3VDC and has a very nice internal
switching regulator (low dropout voltage). The original WRT54G was
supplied with a 5VDC wall wart and had a really small voltage
regulator, while later models came with 12VDC wall warts and a big
TO-220 size regulator.
http://www.linksysinfo.com/modules.php?name=Content&pa=...

The wide voltage range also means that you can easily build your own
PoE contraption and tolerate quite a bit of voltage loss in the CAT5
cableing. If you can get 5VDC or more up the pole, it will work.
See:
http://www.gweep.net/%7Esfoskett/tech/poecalc.html
for calculating the losses. I think (not sure) the WRT54G uses 0.6A
at 12VDC (or about 7 watts). With a switching regulator, the power
dissipation is fairly constant, regardless of input voltage.
Therefore, at 5VDC input, the box would draw about 1.5A.

Oh yeah, how to build your own PoE adapter.
http://www.nycwireless.net/poe/

>I have another quick question: is the LinkSys power adapter
>multi-standard (110 to 230 V)?

No. Looks like different wall warts for 117 and 230VAC.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
Related resources
Anonymous
October 11, 2004 6:05:57 PM

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

meATprivacyDOTnet wrote:




> Hi,
> I am going to buy a couple of LinkSys WRT54GS wireless routers to set
> up
> an external wi-fi bridge (about 340 meters).

> I will put the LinkSys routers on the roofs of the two houses and I
> want
> to bring them the electrical power with the ethernet cable (power over
> ethernet).

> How can I do that?
> Is there any kit I can buy?

> I have another quick question: is the LinkSys power adapter
> multi-standard (110 to 230 V)?

> Thanks a lot.

These are not POE-comliant (IEEE 802.3af) devices, so you will not be
able to buy a ready-made midspan power source. However, you can still make
yourself a couple of adapters out of RJ45 jacks and 3.5 mm coaxial power
plugs. pairs #1 and #4 are not used in a 10/100 Ehternet connection, so
you can solder, say #1 (white/blue-blue) to ground and #4
(white/brown-brown) to the plus ends of your power plugs. If you are
running very long wires, you may have to use higher voltage wall power
supplies to accommodate for the voltage drop in the UTP cable

--
Dmitri Abaimov, RCDD
http://www.cabling-design.com
Cabling Forum, color codes, pinouts and other useful resources for
premises cabling users and pros
http://www.cabling-design.com/homecabling
Residential Cabling Guide
-------------------------------------





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October 11, 2004 7:08:59 PM

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

Yeah, the Screen Savers did something like that on their G4/TechTV show last
week I think. You might want to go up on their website and read their
article on it. I think they said they got it from another source and will
probably give a website for it.


"meATprivacyDOTnet" <me@privacy.net> wrote in message
news:2sv4baF1no611U1@uni-berlin.de...
> Hi,
> I am going to buy a couple of LinkSys WRT54GS wireless routers to set up
> an external wi-fi bridge (about 340 meters).
>
> I will put the LinkSys routers on the roofs of the two houses and I want
> to bring them the electrical power with the ethernet cable (power over
> ethernet).
>
> How can I do that?
> Is there any kit I can buy?
>
> I have another quick question: is the LinkSys power adapter multi-standard
> (110 to 230 V)?
>
> Thanks a lot.
October 11, 2004 9:01:40 PM

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

I dunno about the 5VDC part and the WRT54GS. When I first set up my
WRT54GS, I tried the 5VDC supply that came with my BEFw11s4 v2 (too lazy
to untangle the cords under the desk) - didn't work, no lights.

Of course the WRT54GS did start right up when the 12VDC "wall wart" :) 
was used.

Lance
*****

Jeff Liebermann thought carefully and wrote on 10/11/2004 9:46 AM:
> On Mon, 11 Oct 2004 12:07:38 +0200, meATprivacyDOTnet <me@privacy.net>
> wrote:
>
>
>>I am going to buy a couple of LinkSys WRT54GS wireless routers to set up
>>an external wi-fi bridge (about 340 meters).
>
>
> I don't thin the WRT54GS will play transparent bridge. Methinks the
> WAP54G is what you probably want. If you only want to bridge one
> computah, then the WRT54GS at one end, and just about anything on the
> other end, will work.
>
>
>>I will put the LinkSys routers on the roofs of the two houses and I want
>>to bring them the electrical power with the ethernet cable (power over
>>ethernet).
>>
>>How can I do that?
>>Is there any kit I can buy?
>
>
> Linksys WAPPOE
> http://www.linksys.com/products/product.asp?prid=582&sc...
> Note the list of supported products. I find it interesting that the
> WRT54G is supported. The WAPPOE box outputs 5VDC while the Linksys
> WRT54G allegedly runs on 12VDC. Well the answer is that the WRT54G
> will run on just about anything between 5VDC and about 18VDC. That's
> because internally, it runs on 3.3VDC and has a very nice internal
> switching regulator (low dropout voltage). The original WRT54G was
> supplied with a 5VDC wall wart and had a really small voltage
> regulator, while later models came with 12VDC wall warts and a big
> TO-220 size regulator.
> http://www.linksysinfo.com/modules.php?name=Content&pa=...
>
> The wide voltage range also means that you can easily build your own
> PoE contraption and tolerate quite a bit of voltage loss in the CAT5
> cableing. If you can get 5VDC or more up the pole, it will work.
> See:
> http://www.gweep.net/%7Esfoskett/tech/poecalc.html
> for calculating the losses. I think (not sure) the WRT54G uses 0.6A
> at 12VDC (or about 7 watts). With a switching regulator, the power
> dissipation is fairly constant, regardless of input voltage.
> Therefore, at 5VDC input, the box would draw about 1.5A.
>
> Oh yeah, how to build your own PoE adapter.
> http://www.nycwireless.net/poe/
>
>
>>I have another quick question: is the LinkSys power adapter
>>multi-standard (110 to 230 V)?
>
>
> No. Looks like different wall warts for 117 and 230VAC.
>
>
October 11, 2004 9:50:39 PM

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

Linksys make a POE kit for the WRT54G.
Check out
http://www.linksys.com/products/product.asp?grid=36&sci...



"meATprivacyDOTnet" <me@privacy.net> wrote in message
news:2sv4baF1no611U1@uni-berlin.de...
> Hi,
> I am going to buy a couple of LinkSys WRT54GS wireless routers to set up
> an external wi-fi bridge (about 340 meters).
>
> I will put the LinkSys routers on the roofs of the two houses and I want
> to bring them the electrical power with the ethernet cable (power over
> ethernet).
>
> How can I do that?
> Is there any kit I can buy?
>
> I have another quick question: is the LinkSys power adapter multi-standard
> (110 to 230 V)?
>
> Thanks a lot.
Anonymous
October 11, 2004 10:02:39 PM

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

On Mon, 11 Oct 2004 17:01:40 -0700, Lance <lltbhill@link_earth.net>
wrote:

>I dunno about the 5VDC part and the WRT54GS. When I first set up my
>WRT54GS, I tried the 5VDC supply that came with my BEFw11s4 v2 (too lazy
>to untangle the cords under the desk) - didn't work, no lights.
>
>Of course the WRT54GS did start right up when the 12VDC "wall wart" :) 
>was used.

Oops, y'er partly right. Thanks.
Methinks I see what happened. The various photos at:
http://www.linksysinfo.com/modules.php?name=Content&pa=...
don't look anything like the photo on the FCC web pile
(FCCID: Q87-WRT54GP2):
https://gullfoss2.fcc.gov/prod/oet/forms/blobs/retrieve...
Note the much larger number of components including the *DUAL* TO-220
case 5 terminal switching regulators. The ones in the photo from
Linksysinfo site show single regulators. I guess(tm) there are
variations in the design. I know for sure that a WRT54G v1.1 will
work at about 7-8VDC because I have one running on a pole. No clue on
the v2.0 flavour but I can try it in a few days.

Incidentally, unlike your BEFW11S4 v2 incantation, my BEFW11S4 v4 uses
a 12VDC 1A wall wart. Do you see a trend here? Just for fun, I'll
stick it on a variable voltage power supply and try it at lower
voltages. It's not the same as the WRT54G, but it would still be
interesting. If I'm wrong....well, I don't wanna think about it.

Drivel: I guess PoE is nice because it only uses one cable, but for
home use, maybe running a 2nd CAT5 cable and using it solely for power
might be much easier than the RJ45 connector wiring pretzel.


--
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
October 11, 2004 10:41:28 PM

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

On Mon, 11 Oct 2004 18:02:39 -0700, Jeff Liebermann
<jeffl@comix.santa-cruz.ca.us> wrote:

>Incidentally, unlike your BEFW11S4 v2 incantation, my BEFW11S4 v4 uses
>a 12VDC 1A wall wart. Do you see a trend here? Just for fun, I'll
>stick it on a variable voltage power supply and try it at lower
>voltages. It's not the same as the WRT54G, but it would still be
>interesting. If I'm wrong....well, I don't wanna think about it.

I'm right. The BEFW11S4 v4 stock wall wart is 12VDC 1A, but the unit
works just fine down 3.7VDC at 0.7A. See:
http://www.LearnByDestroying.com/pics/drivel/slides/low...
The power supply is a bit difficult to read, but full scale is 6VDC.
I had no problems with startup at 3.7VDC.

This is obviously not the same as a WRT54G or your v2 model, but my
guess(tm) is that the internal switching power supply designs are
similar. The problem might have been that your 5VDC wall wart was
gutless and could not supply the necessary current. At 5VDC, I
measure 0.62A. So much for that idea as I think the Linksys 5VDC wall
warts are 1.5A to 3.0A. Try it again.

Anyways, with such a huge allowable voltage DC input voltage range,
you could just run almost any type of wire from the stock 12VDC wall
wart and almost ignore the copper losses.

--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
October 11, 2004 11:45:37 PM

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

Jeff Liebermann thought carefully and wrote on 10/11/2004 6:41 PM:
> On Mon, 11 Oct 2004 18:02:39 -0700, Jeff Liebermann
> <jeffl@comix.santa-cruz.ca.us> wrote:
>
>
>>Incidentally, unlike your BEFW11S4 v2 incantation, my BEFW11S4 v4 uses
>>a 12VDC 1A wall wart. Do you see a trend here? Just for fun, I'll
>>stick it on a variable voltage power supply and try it at lower
>>voltages. It's not the same as the WRT54G, but it would still be
>>interesting. If I'm wrong....well, I don't wanna think about it.
>
>
> I'm right. The BEFW11S4 v4 stock wall wart is 12VDC 1A, but the unit
> works just fine down 3.7VDC at 0.7A. See:
> http://www.LearnByDestroying.com/pics/drivel/slides/low...
> The power supply is a bit difficult to read, but full scale is 6VDC.
> I had no problems with startup at 3.7VDC.
>
> This is obviously not the same as a WRT54G or your v2 model, but my
> guess(tm) is that the internal switching power supply designs are
> similar. The problem might have been that your 5VDC wall wart was
> gutless and could not supply the necessary current. At 5VDC, I
> measure 0.62A. So much for that idea as I think the Linksys 5VDC wall
> warts are 1.5A to 3.0A. Try it again.
>
> Anyways, with such a huge allowable voltage DC input voltage range,
> you could just run almost any type of wire from the stock 12VDC wall
> wart and almost ignore the copper losses.

The supply that came with the BEFW11S4 v2 has these specs on the unit:

Input: 100-240V 50/60Hz 0.5A
Output: DC5.0V 2.5A

I tried it again and am embarrassed to see that the WRT54GS does indeed
work with this 5VDC supply. I don't know what happened the first time.

Lance
*****
Anonymous
October 12, 2004 12:21:04 AM

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

On Mon, 11 Oct 2004 19:45:37 -0700, Lance <lltbhill@link_earth.net>
wrote:

>The supply that came with the BEFW11S4 v2 has these specs on the unit:
> Input: 100-240V 50/60Hz 0.5A
> Output: DC5.0V 2.5A

That should be more than enough to supply the necessary 0.7A at 5VDC.

Drivel: I have a large number of totally dead 5VDC 3A power supplies
in the office that came from mostly Netgear and Edimax boxes. No clue
why they died, but these are the only dead wall warts that I've seen
in several years. It makes me wonder if there was a bad batch of 5VDC
wall warts and Linksys substituted 12VDC versions because they were
more reliable (or cheaper). Dunno.

>I tried it again and am embarrassed to see that the WRT54GS does indeed
>work with this 5VDC supply. I don't know what happened the first time.

Oh good. I just hate being wrong. When that happens, I get very
depressed, tend to stop answering questions, and revert back to doing
paying work, cleaning the house, shovelling office paperwork, and
generally doing useful things. It's good to know that I won't have to
do all that.


--
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
October 12, 2004 2:40:24 PM

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

On 10/11/04 5:08 PM, Mike wrote:
> Yeah, the Screen Savers did something like that on their G4/TechTV show last
> week I think. You might want to go up on their website and read their
> article on it. I think they said they got it from another source and will
> probably give a website for it.

I went to their website
(<http://www.g4techtv.com/screensavers/index.html&gt;), but I couldn't find
anything about the LinkSys wireless router ...

Do you have a direct link?

Thanks.
Anonymous
October 12, 2004 4:23:53 PM

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

On 10/11/04 6:46 PM, Jeff Liebermann wrote:

> I don't thin the WRT54GS will play transparent bridge. Methinks the
> WAP54G is what you probably want. If you only want to bridge one
> computah, then the WRT54GS at one end, and just about anything on the
> other end, will work.

You are right: the WRT54GS doesn't seem to support bridging with the
official LinkSys firmware, but it looks like the unofficial Sveasoft
firmware adds that functionality:
<http://www.dslreports.com/forum/remark,11069890&gt;

Here is a bridging HOWTO for the WRT54G, it should work fine for the
WRT54GS too, since the Sveasoft firmware is the basically same for both
routers:
<http://www.dslreports.com/forum/remark,10682572&gt;

It looks like the bridging feature is WDS compliant.

Do you think it will work fine and have similar performances to the WAP54G?

I would like to buy the WRT54GS over the WAP54G because it has better
hardware: faster CPU, more flash memory, more RAM ...

Also, it has the SpeedBooster feature.

Thanks.
Anonymous
October 12, 2004 4:23:54 PM

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

On Tue, 12 Oct 2004 12:23:53 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>On 10/11/04 6:46 PM, Jeff Liebermann wrote:
>
>> I don't thin the WRT54GS will play transparent bridge. Methinks the
>> WAP54G is what you probably want. If you only want to bridge one
>> computah, then the WRT54GS at one end, and just about anything on the
>> other end, will work.

>You are right: the WRT54GS doesn't seem to support bridging with the
>official LinkSys firmware, but it looks like the unofficial Sveasoft
>firmware adds that functionality:
><http://www.dslreports.com/forum/remark,11069890&gt;
>
>Here is a bridging HOWTO for the WRT54G, it should work fine for the
>WRT54GS too, since the Sveasoft firmware is the basically same for both
>routers:
><http://www.dslreports.com/forum/remark,10682572&gt;

I'm suspicious. Simply disabling the DHCP server and ignoring the WAN
port on a wireless router does not magically make it into a
transparent bridge. By transparent, I mean that it has a built in
protocol to duplicate the bridging (MAC to port table) on both ends of
the bridge. Without that, you can't glue two networks together and
pass multiple MAC addresses. Perhaps I missed something, but digging
through the Sveasoft site, I find no such feature described, where two
WRT54G routers are used to bridge two networks.

There was one wireless access point I played with long ago that
offered a bridging mode. At the time, transparent bridges sold for 5
times the cost of an access point, so there was quite an incentive to
advertise bridging features. However, they were apparently in a rush
and didn't do much testing. Wireless traffic seemed excessive, so I
did some sniffing and found that this was a tunnel, not a bridge. It
was passing literally everything in both directions, and not making
any decisions as to whether a packet should cross the bridge. If I
copied a file between two PC's on one side of the wireless bridge, it
would send those packets across the wireless link to nowhere.
However, it did successfully connect (not bridge) two networks.
Fortunately, that firmware mutation never hit the US market.

I really don't wanna get into the various WRT54G modified firmware
issues. I'm not a Linux expert, have only played with the Sveasoft
stuff a little bit, am a really lousy programmist, and are not
terribly interested. There are many WRT54G specific forums that are
inhabited by more experienced users that can better answer your
questions. Meanwhile, I'll just stay suspicious.

>It looks like the bridging feature is WDS compliant.

That's handy, but cuts your bandwidth in half, as does any
store-n-forward scheme.

>Do you think it will work fine and have similar performances to the WAP54G?

I have no idea. I haven't tried it. I suggest you ask in one of the
WRT54G or Linksys specific forums.

>I would like to buy the WRT54GS over the WAP54G because it has better
>hardware: faster CPU, more flash memory, more RAM ...
>
>Also, it has the SpeedBooster feature.
>
>Thanks.


--
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
October 12, 2004 4:36:42 PM

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

On 10/12/04 5:21 AM, Jeff Liebermann wrote:
> On Mon, 11 Oct 2004 19:45:37 -0700, Lance <lltbhill@link_earth.net>
> wrote:
>
>
>>The supply that came with the BEFW11S4 v2 has these specs on the unit:
>> Input: 100-240V 50/60Hz 0.5A
>> Output: DC5.0V 2.5A
>
>
> That should be more than enough to supply the necessary 0.7A at 5VDC.

If I got right your replies, I should be able to run the LinkSys WRT54GS
wifi router using the WAPPOE power over ethernet kit, even if the power
output of the kit is 5V and the "official" power input of the router is 12V.

I just found a D-Link PoE adapter with selectable 5V or 12V power output:

"DWL-P200 Power over Ethernet Adapter"
<http://www.d-link.com/products/?pid=332&gt;

Will it work with the LinkSys WRT54GS router?

If so, is the D-Link adapter a better product than the LinkSys WAPPOE
kit? Which one would you recommend?

Thanks a lot.
Anonymous
October 12, 2004 10:05:50 PM

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

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<spclm096do4idq6cmn7eu4ucdi83d2qj20@4ax.com>...

> Linksys WAPPOE
> http://www.linksys.com/products/product.asp?prid=582&sc...
> Note the list of supported products. I find it interesting that the
> WRT54G is supported. The WAPPOE box outputs 5VDC while the Linksys
> WRT54G allegedly runs on 12VDC. Well the answer is that the WRT54G
> will run on just about anything between 5VDC and about 18VDC.

Glad to see you noticed that, Jeff. Cool ain't it?! Linksys decided
to go from a 5V power supply to a 12V power supply so we could do POE
with no additional hardware. Way cool!

I had an old WAP11 power supply and plugged it into my WRT54G just to
see if the device would run on 5V. Did fine.

Thanks to some young EE at Linksys that nobody even noticed. Hope he
gets a promotion.
Anonymous
October 13, 2004 3:06:34 PM

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

On 10/12/04 6:01 PM, Jeff Liebermann wrote:

> The Dlink is better because Linksys didn't bother to supply any
> technical information with theirs. The 5/12VDC output switch is a big
> plus. However, you might have some problems with different 3.5mm
> connector sizes. Dlink supplies a jumper cable from the DWL-P200 but
> there's no guarantee it will fit the connector on a Linksys product.
> No big deal but some adapting or perhaps soldering may be required.

I think I will go for the D-Link DWL-P200 PoE kit, instead of building
my own custom PoE kit, since I don't have any experience with "Do It
Yourself" stuff ...

Is anyone using the D-Link adapter with a LinkSys product? Do they use
the same 3.5mm connector?

Thanks.
Anonymous
October 13, 2004 3:11:25 PM

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

On 10/12/04 6:30 PM, Jeff Liebermann wrote:

> That's handy, but cuts your bandwidth in half, as does any
> store-n-forward scheme.

Do you mean that putting two "access points" in WDS bridging mode, with
no clients connected to them, will still cut the bandwidth in half?

> I have no idea. I haven't tried it. I suggest you ask in one of the
> WRT54G or Linksys specific forums.

Okay, I am going to check out some forums ...

Thanks.
Anonymous
October 13, 2004 3:11:26 PM

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

On Wed, 13 Oct 2004 11:11:25 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>On 10/12/04 6:30 PM, Jeff Liebermann wrote:
>
>> That's handy, but cuts your bandwidth in half, as does any
>> store-n-forward scheme.

>Do you mean that putting two "access points" in WDS bridging mode, with
>no clients connected to them, will still cut the bandwidth in half?

Chuckle. With no clients connected and moving no traffic, you don't
need any bandwidth.

If you have two WDS enabled access points, where the internet is
connected to one, and the client radio is connected to the 2nd, the
2nd accesses point does store-n-forward (between the first access
point and the client radio. Since the system is half-duplex, and each
packet gets sent twice, the bandwidth is half.

If you junk the WDS repeater idea, and run a CAT5 cable between the
two access points, you avoid the problem.


--
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
October 13, 2004 3:12:52 PM

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

On 10/13/04 3:05 AM, Michael Erskine wrote:

> Glad to see you noticed that, Jeff. Cool ain't it?! Linksys decided
> to go from a 5V power supply to a 12V power supply so we could do POE
> with no additional hardware. Way cool!

What do you mean?

Thanks.
Anonymous
October 13, 2004 3:30:16 PM

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

On 12 Oct 2004 18:05:50 -0700, osiris@deltaville.net (Michael Erskine)
wrote:

>Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<spclm096do4idq6cmn7eu4ucdi83d2qj20@4ax.com>...
>
>> Linksys WAPPOE
>> http://www.linksys.com/products/product.asp?prid=582&sc...
>> Note the list of supported products. I find it interesting that the
>> WRT54G is supported. The WAPPOE box outputs 5VDC while the Linksys
>> WRT54G allegedly runs on 12VDC. Well the answer is that the WRT54G
>> will run on just about anything between 5VDC and about 18VDC.

>Glad to see you noticed that, Jeff. Cool ain't it?! Linksys decided
>to go from a 5V power supply to a 12V power supply so we could do POE
>with no additional hardware. Way cool!

Well, the real inovation was to use a switching regulator in the
router instead of the cheaper inefficient linear power burner. It
keeps the box MUCH cooler. It also makes it tougher to meet FCC and
ISO conducted radiation specification and costs somewhat more. The
real benifit is that the router will run on just about any wall wart
that can be purchased, which compensates for the increased cost of the
circuit. It turns out that the 12VDC wall warts are a bit cheaper,
use more efficient transformers, smaller diodes, smaller filter caps,
and smaller guage output cable. Looks like an all around winner.

Another nice thing is that it will run on either a 6V or 12V gel cell.
No need for DC-DC converters. Add a suitable solar battery charger
and no need for PoE. The voltage can drift around the nominal voltage
and the radio will never notice. Actually, there is a dumb problem at
the upper end. The electrolytic filter cazapitors limit the upper end
regulator can handle. The typical switching regulator can usually
handle up to 40VDC on the input, but the capacitors are usually rated
at 15-18VDC. So, I can't run it on 24VDC (without modification) which
is what I like to use for solar power.

Google found some more on the subject:
http://wiki.personaltelco.net/index.cgi/BatteryPoweredA...

>I had an old WAP11 power supply and plugged it into my WRT54G just to
>see if the device would run on 5V. Did fine.

Oh good. I wasn't quite sure what the WRT54G would do. Looking at
the internal photos, my guess(tm) is that it's the same regulator
circuit.

>Thanks to some young EE at Linksys that nobody even noticed. Hope he
>gets a promotion.

Agreed, although methinks it was designed somewhere in China. Perhaps
it might be useful firing the marketing department that doesn't
understand Open Source firmware, chronically inscribes on the data
sheet the power requirements of the wall wart instead of the router,
fails to specify the number of MAC addresses bridgeable, etc.


--
Jeff Liebermann jeffl@comix.santa-cruz.ca.us
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 AE6KS 831-336-2558
October 13, 2004 6:29:27 PM

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

Try this: http://www.g4techtv.com/videos/index.html?video_key=888...

meATprivacyDOTnet wrote:
> On 10/11/04 5:08 PM, Mike wrote:
>
>> Yeah, the Screen Savers did something like that on their G4/TechTV
>> show last week I think. You might want to go up on their website and
>> read their article on it. I think they said they got it from another
>> source and will probably give a website for it.
>
>
> I went to their website
> (<http://www.g4techtv.com/screensavers/index.html&gt;), but I couldn't find
> anything about the LinkSys wireless router ...
>
> Do you have a direct link?
>
> Thanks.
Anonymous
October 13, 2004 9:31:55 PM

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

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<arqqm01hk93o9qksib8p162tnc47fn8mtf@4ax.com>...
> On 12 Oct 2004 18:05:50 -0700, osiris@deltaville.net (Michael Erskine)
> wrote:
>
> >Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<spclm096do4idq6cmn7eu4ucdi83d2qj20@4ax.com>...
> >
> >> Linksys WAPPOE
> >> http://www.linksys.com/products/product.asp?prid=582&sc...
> >> Note the list of supported products. I find it interesting that the
> >> WRT54G is supported. The WAPPOE box outputs 5VDC while the Linksys
> >> WRT54G allegedly runs on 12VDC. Well the answer is that the WRT54G
> >> will run on just about anything between 5VDC and about 18VDC.
>
> >Glad to see you noticed that, Jeff. Cool ain't it?! Linksys decided
> >to go from a 5V power supply to a 12V power supply so we could do POE
> >with no additional hardware. Way cool!
>
> Well, the real inovation was to use a switching regulator in the
> router instead of the cheaper inefficient linear power burner. It
> keeps the box MUCH cooler. It also makes it tougher to meet FCC and
> ISO conducted radiation specification and costs somewhat more. The
> real benifit is that the router will run on just about any wall wart
> that can be purchased, which compensates for the increased cost of the
> circuit. It turns out that the 12VDC wall warts are a bit cheaper,
> use more efficient transformers, smaller diodes, smaller filter caps,
> and smaller guage output cable. Looks like an all around winner.
>
> Another nice thing is that it will run on either a 6V or 12V gel cell.
> No need for DC-DC converters. Add a suitable solar battery charger
> and no need for PoE. The voltage can drift around the nominal voltage
> and the radio will never notice. Actually, there is a dumb problem at
> the upper end. The electrolytic filter cazapitors limit the upper end
> regulator can handle. The typical switching regulator can usually
> handle up to 40VDC on the input, but the capacitors are usually rated
> at 15-18VDC. So, I can't run it on 24VDC (without modification) which
> is what I like to use for solar power.
>
> Google found some more on the subject:
> http://wiki.personaltelco.net/index.cgi/BatteryPoweredA...

Thanks for the info. :)  This device has a pretty solid future if
Sveasoft and some of the others don't destroy the damn thing with
their playing to the "power tweak".

Sveasoft and HyperWART have tweaks in place that let you set power
levels up to 250 mw. I've seen some of the 0-scope signal graphs and
they look pretty clean up to about 80 mw, beyond that they get
questionable. Your thoughts?

-m-
Anonymous
October 14, 2004 3:07:55 PM

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

On Wed, 13 Oct 2004 11:12:52 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>On 10/13/04 3:05 AM, Michael Erskine wrote:
>
>> Glad to see you noticed that, Jeff. Cool ain't it?! Linksys decided
>> to go from a 5V power supply to a 12V power supply so we could do POE
>> with no additional hardware. Way cool!
>
>What do you mean?

I think he means that you don't need all the PoE hardware. The WRT54G
apparently will run on any voltage between 3.7VDC and perhaps 18VDC.
Current drain will vary, but is probably below .7A at 5VDC which is
well within the operating range of the standard 12VDC 1A wall wart.
With such a wide range of acceptable input operating voltages, the
line loss in the CAT5 cable can almost be ignored.

For example, my previous calculations showed that for 100ft of CAT5,
you will have 3 ohms of resistance and lose 3VDC at 1A (worst case).
If we start with our 12VDC wall wart, and lose the 3VDC in the cable,
then the WRT54G is now running off of 12-3 = 9VDC. The WRT54G can
easily run off +9VDC and probably tolerate 3 times as much cable loss.

If you simply run a 2nd CAT5 cable, double up two of the wire pairs,
and power the WRT54G from the 12VDC 1A wall wart, it will work. If
you can't run a 2nd cable, then borrow the 4 extra wires, break out
the wires from the RJ45 connector, attach a 3.5mm power connector, and
use it as a simple extension cable for the power supply.

Use the money you didn't spend on the PoE box on some decent antennas.


--
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
October 14, 2004 10:35:29 PM

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

On 10/13/04 7:52 PM, Jeff Liebermann wrote:

> If you have two WDS enabled access points, where the internet is
> connected to one, and the client radio is connected to the 2nd, the
> 2nd accesses point does store-n-forward (between the first access
> point and the client radio. Since the system is half-duplex, and each
> packet gets sent twice, the bandwidth is half.

Let me explain better my needs: I will use the two LinkSys 'routers'
only to have a Wi-Fi link between two houses (340m distance) to join two
existing Ethernet networks (and also share the Internet connection).

I don't need to connect any wireless client to the two LinkSys
'routers', I'll use them only to run the wireless bridge.

Assuming that the Sveasoft firmware works fine as advertised for
transparent bridging, will I have the full bandwith available for the
Wi-Fi link between the two LinkSys 'routers'?

Thanks a lot.
Anonymous
October 14, 2004 10:35:30 PM

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

On Thu, 14 Oct 2004 18:35:29 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>On 10/13/04 7:52 PM, Jeff Liebermann wrote:
>
>> If you have two WDS enabled access points, where the internet is
>> connected to one, and the client radio is connected to the 2nd, the
>> 2nd accesses point does store-n-forward (between the first access
>> point and the client radio. Since the system is half-duplex, and each
>> packet gets sent twice, the bandwidth is half.

>Let me explain better my needs: I will use the two LinkSys 'routers'
>only to have a Wi-Fi link between two houses (340m distance) to join two
>existing Ethernet networks (and also share the Internet connection).
>
>I don't need to connect any wireless client to the two LinkSys
>'routers', I'll use them only to run the wireless bridge.
>
>Assuming that the Sveasoft firmware works fine as advertised for
>transparent bridging, will I have the full bandwith available for the
>Wi-Fi link between the two LinkSys 'routers'?

Somehow, we drifted into WDS and store and forward repeaters. Neither
of these systems apply in your case. You are apparently building a
simple transparent bridge and nothing more. There will be no halving
of the bandwidth. There will be an increase in system latency caused
by the additional delays in the bridge radios, but that will not
substantially affect thruput. Assuming the Sveasoft firmware works as
expected, you should have no problems.

Well, at 340meters, you will need to put some effort into directional
gain antennas. Don't bother with the PoE. Just run a 2nd CAT5 cable
to the router and use the wires as an extension cable for the stock
12VDC 1A adapter. Judging from my measurements, it will work.

Hint: To get decent answers, always mention what you are trying to
accomplish, and what you have to work with.


--
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
October 14, 2004 10:49:06 PM

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

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<d2srm09pm2roh4sa088rsvdmt219mpj5a8@4ax.com>...

Thanks Jeff, most of that was over my head but I got the gist.

Thanks.
-m-
Anonymous
October 15, 2004 12:54:33 PM

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

On 14 Oct 2004 18:49:06 -0700, osiris@deltaville.net (Michael Erskine)
wrote:

>Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<d2srm09pm2roh4sa088rsvdmt219mpj5a8@4ax.com>...
>
>Thanks Jeff, most of that was over my head but I got the gist.

Well, I could explain myself, but it took long enough to grind out the
answer.

Google found these spectrum analyzer photos:
http://explorer.cyberstreet.com/wrt54g/WRT54g-spectralo...
which show the effect of changing power levels. The problem is that
the person that took the photos didn't include the graticule markings.
If he had, I would have overlayed the FCC spectral purity limits on
the images to see if they're legal. Without the markers, I can't do
much. He also didn't bother setting the max power to a fixed on
screen reference level so the RELATIVE increase in sideband junk can
be measured.

If I dive into the directory at:
http://explorer.cyberstreet.com/wrt54g/
there are some larger photos where I can barely see the graticule.
However, I got better things to do than clean up this mess. The photos
were apparently taken with a hand digital camera. Each one appears a
slightly different size, slightly out of focus, and slightly rotated.
Too much work.

Just looking at the 100, 150, 200, and 250mw level photos, the "grass"
at the bottom of the picture is climbing rapidly. That's going to
slop into the adjacent channels causeing problems with other users,
and with adjacent out of band services.


--
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
October 15, 2004 3:19:19 PM

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

On 10/14/04 7:59 PM, Jeff Liebermann wrote:

> Well, at 340meters, you will need to put some effort into directional
> gain antennas. Don't bother with the PoE. Just run a 2nd CAT5 cable
> to the router and use the wires as an extension cable for the stock
> 12VDC 1A adapter. Judging from my measurements, it will work.

I am considering to get a couple of parabolic antennas by Stella Doradus:
<http://www.stelladoradus.com/2.4para.shtml&gt;

Is it a good brand/model?

I am considering the '24 SD19' one with a gain of 19 dBi:
<http://www.stelladoradus.com/pdfs/2.4/parabolic/grid/24...;

Is it 'powerful' enough for my radio bridge of 340 meters?
There are a two lines of oak trees in the line of sight of the two
wireless 'routers'.

Let me know if you have any suggestion about a better brand/model for
the directional antennas.

Thanks a lot.
Anonymous
October 15, 2004 3:19:20 PM

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

On Fri, 15 Oct 2004 11:19:19 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>I am considering to get a couple of parabolic antennas by Stella Doradus:
><http://www.stelladoradus.com/2.4para.shtml&gt;
>Is it a good brand/model?
>I am considering the '24 SD19' one with a gain of 19 dBi:
><http://www.stelladoradus.com/pdfs/2.4/parabolic/grid/24...;

They look nice (and expensive) but I have no experience with that
brand. Perhaps it would be entertaining to do some calculations
before you start?

>Is it 'powerful' enough for my radio bridge of 340 meters?

Well, let's do some numbers first:
http://www.ydi.com/calculation/som.php
For this to work, you would need an absolute minimum of 10dB fade
margin. Plugging in:
+15dBm tx power
-2dB tx and rx cable losses
340 meters = 0.211 miles
-81dBm rx sensitivity
I find that a pair of 8dBi antennas will yield a 17.3dB fade margin.
This is "good enough" assuming my guesswork is correct, and that you
have line of sight with Fresnel zone clearance.

>There are a two lines of oak trees in the line of sight of the two
>wireless 'routers'.

Forget it. It will NOT work. 2.4GHz will NOT go through broad leaf
trees. If the trees are small and you can see through them, you might
be able to sneak some 5.6Ghz through the holes, but you would still
have a rather poor and unstable signal.

>Let me know if you have any suggestion about a better brand/model for
>the directional antennas.

I use Pacific Wireless "barbeque grill" type antennas.
http://www.fab-corp.com/B1.htm
http://www.pacwireless.com
However, they won't work through the trees.


--
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
October 15, 2004 4:42:05 PM

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

On 10/13/04 11:06 AM, meATprivacyDOTnet wrote:

> I think I will go for the D-Link DWL-P200 PoE kit, instead of building
> my own custom PoE kit, since I don't have any experience with "Do It
> Yourself" stuff ...

Since it looks like that WRT54GS works fine with both 5V or the 12V
input, will it run cooler with the 5V or 12V input?

I'll be putting the WRT54GS in a sealed box on the house's roof and I
want to keep it running as cool as possible ...

Thanks.
Anonymous
October 15, 2004 4:42:06 PM

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

On Fri, 15 Oct 2004 12:42:05 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>On 10/13/04 11:06 AM, meATprivacyDOTnet wrote:
>
>> I think I will go for the D-Link DWL-P200 PoE kit, instead of building
>> my own custom PoE kit, since I don't have any experience with "Do It
>> Yourself" stuff ...
>
>Since it looks like that WRT54GS works fine with both 5V or the 12V
>input, will it run cooler with the 5V or 12V input?

The dissipation will be least at the lower voltages. Remember the
power consumption measurements I previously posted for my BEFW11s4?
voltage * current = watts
3.7VDC 0.70A 2.6W
5.0VDC 0.62A 3.1W
13.8VDC 0.4A 5.5W
If the built in switching supply had been "perfect", it would have
been constant power dissipation (watts), but real design doesn't work
that way.

Just remember that to end up with 5VDC at the WRT54G, you need to
consider the cabling loss. With 0.5A current, 100ft of CAT5, you will
lose about 1.5VDC. Therefore, you'll need 5.0 + 1.5 = 6.5VDC power
supply minimum.

>I'll be putting the WRT54GS in a sealed box on the house's roof and I
>want to keep it running as cool as possible ...

There was a really nice 8 page article on the Sveasoft web pile
showing how one person in Sweden did this. Now, I can't find it.


--
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
October 15, 2004 11:44:42 PM

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

meATprivacyDOTnet <me@privacy.net> wrote:

> I'll be putting the WRT54GS in a sealed box on the house's roof and I
> want to keep it running as cool as possible ...

You don't want a completely sealed box... I don't think.
There should be a "weep" hole at the bottom to allow for thermal changes,
both ambient and equipment caused. In a bad weather environment, you might
cover it with Goretex, but a small hole facing down is probably okay.
I recall that both of these covered that topic.

David Taylor's is a good story and good writeup.
http://www.nodomainname.co.uk/Equation/equation_broadba...

Craig's is a long link, with good mapping detail.
http://www.craig-bartell.com/

--
---
Clarence A Dold - Hidden Valley (Lake County) CA USA 38.8-122.5
Anonymous
October 15, 2004 11:44:43 PM

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

On Fri, 15 Oct 2004 19:44:42 +0000 (UTC),
dold@XReXXLinkS.usenet.us.com wrote:

>meATprivacyDOTnet <me@privacy.net> wrote:
>
>> I'll be putting the WRT54GS in a sealed box on the house's roof and I
>> want to keep it running as cool as possible ...

>You don't want a completely sealed box... I don't think.

Well maybe. I've been going the pressurized route since I've found
some military surplus waterproof connectors. A bicycle valve stem and
a bit of compressed dry air work quite nicely. However, things don't
always work as expected. Climbing a tower in the rain to deal with a
flakey internal connector found me pumping a bicycle pump on a 60 ft
tower. No fun. Another box was made from plastic that became soft in
the heat of the sun. The box now looks like a distorted balloon (but
is still holding pressure). I've been experimenting with pressurizing
a NEMA box though a long plastic hose to the base of the tower. That
seems to be working so far.

If you can't pressurize, then a drain hole is a good idea. Without
pressure, water will collect inside no matter what you do. Might as
well give it a place to go.

>There should be a "weep" hole at the bottom to allow for thermal changes,
>both ambient and equipment caused. In a bad weather environment, you might
>cover it with Goretex, but a small hole facing down is probably okay.
>I recall that both of these covered that topic.

Yep. See:
http://www.google.com/groups?q=sealed+box+group:alt.int...
Several other articles on the subject in the threat.


--
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
October 15, 2004 11:44:44 PM

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

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote:
>dold@XReXXLinkS.usenet.us.com wrote:
>>You don't want a completely sealed box... I don't think.

>Well maybe. I've been going the pressurized route since I've found
>some military surplus waterproof connectors.

My weather station and radio repeater are in a Nema-4 sealed box with
all the wires leading thru a large hole that's filled with Coax-Seal
around the wires. It's not perfectly sealed, but it's pretty good,
and the ~4 kilograms of desiccant keep it nice and dry inside. I
replace or recharge the desiccant yearly, and it only gets up to about
(lessee...) 30 percent RH over the course of the year.

http://compusmiths.com/TowerBase.jpg
Anonymous
October 16, 2004 12:34:30 AM

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

Jeff Liebermann <jeffl@comix.santa-cruz.ca.us> wrote in message news:<dnrvm05u385dn8v3pdn3qukv3qedfrbum5@4ax.com>...

Don't worry yourself. I told them what you said, already, even before
you said it but ... I didn't really know what I was talking about. I
just had this gut feeling thing (funny how the Fort did that to me :) 
) ... Sometimes I still wonder at it. How do I *KNOW* these things
when I don't understand them... well, There is NO substitute for
understanding them. So...

I told them what you said before you said it and now I have pointed
them to what you have said. I do wish I could explain it like you can.

Thanks.
-m-
Anonymous
October 16, 2004 3:06:05 PM

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

On 10/15/04 5:24 PM, Jeff Liebermann wrote:

> Just remember that to end up with 5VDC at the WRT54G, you need to
> consider the cabling loss. With 0.5A current, 100ft of CAT5, you will
> lose about 1.5VDC. Therefore, you'll need 5.0 + 1.5 = 6.5VDC power
> supply minimum.

I think I'll go for the D-Link DWL-P200 PoE adapter and set the output
power to 5V.
I have no experience with DIY stuff ...

> There was a really nice 8 page article on the Sveasoft web pile
> showing how one person in Sweden did this. Now, I can't find it.

Here is the link:
<http://www.sveasoft.com/articles/armored/&gt;

It is indeed a good article, I am not so inclined as to do all that
customization work, I'll probably just put the WRT54GS wireless router
in a waterproof box and drill a small hole at the bottom.

Do you think it will run much hotter than if I disassembled it?

Thanks.
Anonymous
October 16, 2004 3:25:29 PM

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

On 10/15/04 5:37 PM, Jeff Liebermann wrote:

> They look nice (and expensive) but I have no experience with that
> brand. Perhaps it would be entertaining to do some calculations
> before you start?

Actually I don't think it is very expensive, it is about 40 euro in Italy.

> I find that a pair of 8dBi antennas will yield a 17.3dB fade margin.
> This is "good enough" assuming my guesswork is correct, and that you
> have line of sight with Fresnel zone clearance.

Excuse my ignorance, what is the Frensel zone clearance?

What if I use 19dBi antennas instead of the 8dBi ones?
Will they be too 'powerful' for my needs? Will I have problems with them?

> Forget it. It will NOT work. 2.4GHz will NOT go through broad leaf
> trees. If the trees are small and you can see through them, you might
> be able to sneak some 5.6Ghz through the holes, but you would still
> have a rather poor and unstable signal.

A friend of mine was able to set up a 2.4Ghz Wi-Fi bridge (11Mbps) going
through a couple of oak trees, it looks like he didn't have a big
problems with them. Was he just lucky?

I could use a couple of poles to try to put the antennas the trees, do
you think it is worth a try?

> I use Pacific Wireless "barbeque grill" type antennas.
> http://www.fab-corp.com/B1.htm
> http://www.pacwireless.com

They look great, but I am not sure where to get them in Italy.

Thanks.
Anonymous
October 16, 2004 3:25:30 PM

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

On Sat, 16 Oct 2004 11:25:29 +0200, meATprivacyDOTnet <me@privacy.net>
wrote:

>On 10/15/04 5:37 PM, Jeff Liebermann wrote:
>
>> They look nice (and expensive) but I have no experience with that
>> brand. Perhaps it would be entertaining to do some calculations
>> before you start?

>Actually I don't think it is very expensive, it is about 40 euro in Italy.

That's about $50 US. Good price. I pay about the same for Pacific
Wireless 19dBi dishes.

>Excuse my ignorance, what is the Frensel zone clearance?

Sigh. Optical line of sight is not sufficient to insure reliable
communications between two points. At microwave frequencies, knife
edge diffraction will cause signal loss if there are objects within
the Fresnel zone. It's not a big problem for relatively short
distances, but is a real problem for long ranges. The first Fresnel
zone for your 340m link is a radius of 0.43 meters. That means that
in the middle of your your link, you need a 0.86 meter diameter
clearance, or you will have signal loss problem.
http://www.ydi.com/calculation/fresnel-zone.php
Note that means ANY object including trees.

>What if I use 19dBi antennas instead of the 8dBi ones?
>Will they be too 'powerful' for my needs? Will I have problems with them?

You haven't told me anything about the trees. As far as I'm
concerned, it probably will NOT work through one row of trees, and
certainly will NOT work through two rows of trees. Can you see
through the trees? If not, you don't have a chance.

Here's what one person did to go through trees at 1000ft.
http://trevormarshall.com/lapierre.htm

>A friend of mine was able to set up a 2.4Ghz Wi-Fi bridge (11Mbps) going
>through a couple of oak trees, it looks like he didn't have a big
>problems with them. Was he just lucky?

Yes. I have a few links that go through trees. During the winter,
they work fine. When spring arrives, the leaves appear and the signal
drops dramatically. I've fixed the problem with pruning shears
instead of antenna gain. Tell me about the trees, or find a photo,
and we'll see. However, there's a big difference between "a couple of
oak trees" and "two rows of oak trees".

>I could use a couple of poles to try to put the antennas the trees, do
>you think it is worth a try?

Anything you do to avoid the trees will be what is required for this
to work.


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