Alternate to wireless, or is WIFI the right solution?

I have recently been bequeathed by our local phone company with a
low-bandwidth DSL connection - 1.5mbs - after ten years of waiting for "high
speed" service in our area.

I have two buildings about 400' apart serviced by the same incoming phone
line (telco provided connection, common to both buildings).

I'd like to have the DSL service available in both at once, but realize I
cannot put two DSL modems on the same line.

So... can I reasonably run a line-of-site WIFI link between the buildings
(400'?), or should I run wires (quite inconvenient, but possible... just not
pretty, with plumbing, wires, etc in the ground). Is there a simple
ethernet bridge that'll run 1.5mbs over a buried UTP line that far? What
about when(if) they ever upgrade to 6mbps?

Thanks.

LLoyd


--
"... Some mornings, it's just not worth chewing through the restraints."

"Lloyd E. Sponenburgh" <lloydsp@mindspring.com> wrote in message
news:466d3530$0$30666$4c368faf@roadrunner.com...
>I have recently been bequeathed by our local phone company with a
>low-bandwidth DSL connection - 1.5mbs - after ten years of waiting for
>"high speed" service in our area.
>
> I have two buildings about 400' apart serviced by the same incoming phone
> line (telco provided connection, common to both buildings).
>
> I'd like to have the DSL service available in both at once, but realize I
> cannot put two DSL modems on the same line.
>
> So... can I reasonably run a line-of-site WIFI link between the buildings
> (400'?), or should I run wires (quite inconvenient, but possible... just
> not pretty, with plumbing, wires, etc in the ground). Is there a simple
> ethernet bridge that'll run 1.5mbs over a buried UTP line that far? What
> about when(if) they ever upgrade to 6mbps?
>
> Thanks.
>
> LLoyd
>
>
> --
> "... Some mornings, it's just not worth chewing through the restraints."
>


Two wireless access points (not routers) with directional antenna will do
the trick - as long as you have direct line of sight between the two
buildings.

I am doing that now with two old Linksys WAP11 access points - connecting
two buildings that are about 100 feet apart - using the standard antenna's
that came with the units.

Lloyd E. Sponenburgh wrote:
> So... can I reasonably run a line-of-site WIFI link between the
> buildings (400'?), or should I run wires (quite inconvenient, but
> possible... just not pretty, with plumbing, wires, etc in the ground).
> Is there a simple ethernet bridge that'll run 1.5mbs over a buried UTP
> line that far?

A real simple and low cost solution would be a Linksys WRT54G wireless
router as your access point and a Linksys WAP54G Access Point in client
mode at the other end would work fine. Mount them at different heights -
one at 12 ft. roof level and the other perhaps twice as high.

> What about when(if) they ever upgrade to 6mbps?

Keep in mind you have to be under something like 5,000 ft. from the DSLAM.
I forget the exact distance off the top of my head at the moment.

"DTC" <no_spam@move_along_folks.foob> wrote in message
news:vibbi.19294$Ut6.18309@newsread1.news.pas.eart hlink.net...
>
> Keep in mind you have to be under something like 5,000 ft. from the DSLAM.
> I forget the exact distance off the top of my head at the moment.

I'm less than 1700' from the DSLAM, but they've got "limited bandwidth" to
the box, according to the East Indian 'expert' I talked with at customer
service. According to them, I'm lucky I've got DSL at all.

LLoyd

"DTC" <no_spam@move_along_folks.foob> wrote in message
news:vibbi.19294$Ut6.18309@newsread1.news.pas.eart hlink.net...
> A real simple and low cost solution would be a Linksys WRT54G wireless
> router as your access point and a Linksys WAP54G Access Point in client
> mode at the other end would work fine. Mount them at different heights -
> one at 12 ft. roof level and the other perhaps twice as high.

I can put up masts as high as 40' without a problem.

I've never done anything with directional antennae on WIFI, just 'local'
APs. Are these available commercially, or am I getting into beer-can
antennae now?

How are they during torrential rain?

Thanks,
LLoyd

"DTC" <no_spam@move_along_folks.foob> wrote in message
news:vibbi.19294$Ut6.18309@newsread1.news.pas.eart hlink.net...
> Mount them at different heights - one at 12 ft. roof level and the other
> perhaps twice as high.
>

Oh... why the different heights? I understand about the "Freznel (aperture?
zone?)" and that one must get the antenna at least as high as half its width
above the ground. But why different heights?

LLoyd

"DTC" <no_spam@move_along_folks.foob> wrote in message
news:vibbi.19294$Ut6.18309@newsread1.news.pas.eart hlink.net...
> A real simple and low cost solution would be a Linksys WRT54G wireless
> router as your access point and a Linksys WAP54G Access Point in client
> mode at the other end would work fine.

Looking at the WRT54G (and already having a WAP54G), I note there's no
external antenna connections on these.

I'm reasonably competent at hacking into and attaching connectors to things
that shouldn't have them. Is this the route(r) to take to attaching the
directional antennae?

I know this one will sound stupid, but here goes.... there are two omnis on
each unit now. Do they get replaced with two differently-polarized
directional arrays, or is one antenna sufficient for each unit?

Thanks,
LLoyd

"Lloyd E. Sponenburgh" <lloydsp@mindspring.com> wrote in message
news:466d3530$0$30666$4c368faf@roadrunner.com...
>I have recently been bequeathed by our local phone company with a
>low-bandwidth DSL connection - 1.5mbs - after ten years of waiting for
>"high speed" service in our area.

Since the FCC considers 256k as broadband. Your 1.5Mbs dsl is not low
bandwidth
>
> I have two buildings about 400' apart serviced by the same incoming phone
> line (telco provided connection, common to both buildings).
>
> I'd like to have the DSL service available in both at once, but realize I
> cannot put two DSL modems on the same line.
>
> So... can I reasonably run a line-of-site WIFI link between the buildings
> (400'?), or should I run wires (quite inconvenient, but possible... just
> not pretty, with plumbing, wires, etc in the ground). Is there a simple
> ethernet bridge that'll run 1.5mbs over a buried UTP line that far? What
> about when(if) they ever upgrade to 6mbps?

Yes to all.
>
> Thanks.
>
> LLoyd
>
>
> --
> "... Some mornings, it's just not worth chewing through the restraints."
>

Lloyd E. Sponenburgh wrote:
> I have recently been bequeathed by our local phone company with a
> low-bandwidth DSL connection - 1.5mbs - after ten years of waiting
> for "high speed" service in our area.
>
> I have two buildings about 400' apart serviced by the same incoming
> phone line (telco provided connection, common to both buildings).
>
> I'd like to have the DSL service available in both at once, but
> realize I cannot put two DSL modems on the same line.
>
> So... can I reasonably run a line-of-site WIFI link between the
> buildings (400'?), or should I run wires (quite inconvenient, but
> possible... just not pretty, with plumbing, wires, etc in the
> ground). Is there a simple ethernet bridge that'll run 1.5mbs over a
> buried UTP line that far? What about when(if) they ever upgrade to
> 6mbps?
> Thanks.
>
> LLoyd

How does the second building get power? If the same phone line, chances are
it's the same power too... Have you looked at powerline networking? doesn't
have to be on the same circuit breaker, just on the same leg off the
transformer (the easiest way to tell, do you have ONE meter for both
buildings? That usually says they are on the same leg off the transformer
(http://www.netgear.com/Products/Powe...tAdapters.aspx
, under $100, faster than wireless at 85 Mbps, so you can upgrade speed
easily on the DSL side).. Use it for most of my wireless/outbuilding
installs.. Still wireless at the ends, just happens to be an alternative
for the wired bridge part... Never have to worry about signal loss (rain,
leaves growing, cars parking etc)... Just put a wap router on the far end
connected to one of the two powerline bridges (DHCP off, same ssid different
channel, and you have instant bridge/wired/wireless for about $150 - extra
$50 for the second wap router....

Lloyd E. Sponenburgh wrote:
> "DTC" <no_spam@move_along_folks.foob> wrote in message
> news:vibbi.19294$Ut6.18309@newsread1.news.pas.eart hlink.net...
>> A real simple and low cost solution would be a Linksys WRT54G
>> wireless router as your access point and a Linksys WAP54G Access
>> Point in client mode at the other end would work fine.
>
> Looking at the WRT54G (and already having a WAP54G), I note there's no
> external antenna connections on these.
>
> I'm reasonably competent at hacking into and attaching connectors to
> things that shouldn't have them. Is this the route(r) to take to
> attaching the directional antennae?
>
> I know this one will sound stupid, but here goes.... there are two
> omnis on each unit now. Do they get replaced with two
> differently-polarized directional arrays, or is one antenna
> sufficient for each unit?
> Thanks,
> LLoyd

Just to confuse you even more, while it has two omnis on it, they are not
equal or split.... the antennas are actually BOTH alternataly switched and
alternate which is active, so you can't do just one.... If you do something
with just one, you are screwed....... (as per your q above, yes, TWO
directional arrays, or tap into the signal before the splitter/switcher and
just have one.....(have no idea where that may be, but others can give you
tech details)

"Peter Pan" <PeterPanNOSPAM@AkamailNOSPAM.com> wrote in message
news:YcCdnUh-doAO8_DbnZ2dnUVZ_hGdnZ2d@comcast.com...
> How does the second building get power? If the same phone line, chances
> are it's the same power too...

They're on separate transformers -- one's a barn/office, the other a home.
But...

> Have you looked at powerline networking? doesn't have to be on the same
> circuit breaker, just on the same leg off the transformer (the easiest way
> to tell, do you have ONE meter for both buildings? That usually says they
> are on the same leg off the transformer
> (http://www.netgear.com/Products/Powe...tAdapters.aspx
> , under $100, faster than wireless at 85 Mbps, so you can upgrade speed
> easily on the DSL side).. Use it for most of my wireless/outbuilding
> installs..

I guess I could run that over any copper between the buildings -- even an
abandoned phone line....?

> Still wireless at the ends, just happens to be an alternative for the
> wired bridge part... Never have to worry about signal loss (rain, leaves
> growing, cars parking etc)... Just put a wap router on the far end
> connected to one of the two powerline bridges (DHCP off, same ssid
> different channel, and you have instant bridge/wired/wireless for about
> $150 - extra $50 for the second wap router....

The cheapest ethernet extender kit I could find so far was about $130
(w/shipping), but good only to 1mbps.

I'll check out the carrier-current stuff, and see if it would suit the need.

LLoyd

On 11 Jun, 16:55, "Peter Pan" <PeterPanNOS...@AkamailNOSPAM.com>
wrote:
> Lloyd E. Sponenburgh wrote:
> > "DTC" <no_spam@move_along_folks.foob> wrote in message
> >news:vibbi.19294$Ut6.18309@newsread1.news.pas.ear thlink.net...
> >> A real simple and low cost solution would be a Linksys WRT54G
> >> wireless router as your access point and a Linksys WAP54G Access
> >> Point in client mode at the other end would work fine.
>
> > Looking at the WRT54G (and already having a WAP54G), I note there's no
> > external antenna connections on these.
>
> > I'm reasonably competent at hacking into and attaching connectors to
> > things that shouldn't have them. Is this the route(r) to take to
> > attaching the directional antennae?
>
> > I know this one will sound stupid, but here goes.... there are two
> > omnis on each unit now. Do they get replaced with two
> > differently-polarized directional arrays, or is one antenna
> > sufficient for each unit?
> > Thanks,
> > LLoyd
>
> Just to confuse you even more, while it has two omnis on it, they are not
> equal or split.... the antennas are actually BOTH alternataly switched and
> alternate which is active, so you can't do just one.... If you do something
> with just one, you are screwed....... (as per your q above, yes, TWO
> directional arrays, or tap into the signal before the splitter/switcher and
> just have one.....(have no idea where that may be, but others can give you
> tech details)- Hide quoted text -
>
> - Show quoted text -

the wrt54g's do have replaceable antenas (they just screw off) if you
use somthing like ddwrt you can turn one antena off and use a
directional antena from someone like hypertek

Lloyd E. Sponenburgh wrote:
>
> I guess I could run that over any copper between the buildings --
> even an abandoned phone line....?
>

Look into both 2 baseT and 10 base T (the T is for twisted pairs, like old
phone lines), the 2 or 10 is the speed in Mbps it can do... (2 would be way
faster than the DSL you have now, and 10 will be faster than what you are
thinking of getting).. They were made to run over old twisted pairs (like
old phone lines), unfortunately, with the desire for bigger numbers, they
are a bit hard to find nowadays
Check http://itech.fgcu.edu/cis/frames/apchapter6/tsld010.htm

What is 10 Base-T?

10Base-T --- standard configuration that allows construction of 10 Mbps
ethernet LANs over unshielded twisted-pair wire.


Under 10 Base-T, workstations are cabled using twisted-pair wire to medium
access units (MAUs). Each MAU normally has a built-in attachment interface
unit (AIU) that can be cabled to a coaxial transceiver attached to a coaxial
cable. Thus, workstations can be configured in a star topology and cabled to
a bus structured backbone cable that serves to interconnect MAUs.
<snipped>

"Peter Pan" <PeterPanNOSPAM@AkamailNOSPAM.com> wrote in message
news:gMSdnbwJc-PR5vDbnZ2dnUVZ_hynnZ2d@comcast.com...
> What is 10 Base-T?
>
> 10Base-T --- standard configuration that allows construction of 10 Mbps
> ethernet LANs over unshielded twisted-pair wire.
>
>
> Under 10 Base-T, workstations are cabled using twisted-pair wire to medium
> access units (MAUs). Each MAU normally has a built-in attachment interface
> unit (AIU) that can be cabled to a coaxial transceiver attached to a
> coaxial cable. Thus, workstations can be configured in a star topology and
> cabled to a bus structured backbone cable that serves to interconnect
> MAUs.

Yep, thanks. I know all that. A Looooong time ago in a land far away, I
was a networking supervisor, long before WIFI was even an itch. I'm even
half-way tempted to try a hank of OSP, direct-burial cat5e over the 400'
just to see if it can wheedle out a useful 5mbs without too many retries to
be useful. But then, I'd sort of be comitting myself to hard-wired... and
I'd like to do this with a 'new' technology, if it's reasonably inexpensive,
and still reliable in the malicious weather we have in Florida in the
summer.

My last 'real' install was in 1999; gigabit fiber in a government hub in
some unnamed Southern US city.

(No, I don't have cleaving and termination tools anymore, so fiber is out --
costy, anyway)

LLoyd

What size data rate are you looking for? If you want a relatively cheap, efficient, and high speed solution for you problem, then I'd suggest checking out a small company called hField Technologies. They have a USB adapter called the Wi-Fire that you could connect to your computer, and it can send and receive signals for up to 1000'. I have one, and I definitely recommend it. I'm not exactly sure how it will do in the Florida rains, but if it's meant for up to 1000' ft, it should do fine for 400' in the rain.

Lloyd E. Sponenburgh wrote:
> "Peter Pan" <PeterPanNOSPAM@AkamailNOSPAM.com> wrote in message
> news:gMSdnbwJc-PR5vDbnZ2dnUVZ_hynnZ2d@comcast.com...
>> What is 10 Base-T?
>>
>> 10Base-T --- standard configuration that allows construction of 10
>> Mbps ethernet LANs over unshielded twisted-pair wire.
>>
>>
>> Under 10 Base-T, workstations are cabled using twisted-pair wire to
>> medium access units (MAUs). Each MAU normally has a built-in
>> attachment interface unit (AIU) that can be cabled to a coaxial
>> transceiver attached to a coaxial cable. Thus, workstations can be
>> configured in a star topology and cabled to a bus structured
>> backbone cable that serves to interconnect MAUs.
>
> Yep, thanks. I know all that. A Looooong time ago in a land far
> away, I was a networking supervisor, long before WIFI was even an
> itch. I'm even half-way tempted to try a hank of OSP, direct-burial
> cat5e over the 400' just to see if it can wheedle out a useful 5mbs
> without too many retries to be useful. But then, I'd sort of be
> comitting myself to hard-wired... and I'd like to do this with a
> 'new' technology, if it's reasonably inexpensive, and still reliable
> in the malicious weather we have in Florida in the summer.
>
> My last 'real' install was in 1999; gigabit fiber in a government hub
> in some unnamed Southern US city.
>
> (No, I don't have cleaving and termination tools anymore, so fiber is
> out -- costy, anyway)
>
> LLoyd

Point was to use what you have.. You said you already had an abandoned phone
line (twisted pair), running between the buldings, and wanted something
faster than your current 1.5 DSL (hence 2base t), and faster than a new DSL
at 6 Mbps speed (hence the 10 base t)... As I recall from when I did that, a
few years ago, on an old phone line to my garage, got the devices off ebay
for about $20 (old star net stuff)... In place of the MAU's on the above,
used WRT (Wap router) both inside and in the outbuilding which gave me both
wired and wireless in both places (Linksys WRT54G at walmart for $48).. Did
it both in Idaho and Tampa FL area (foliage growing, and bad weather, really
screwed up wireless outside) I'm guessing that since you aren't the
government, you probably want to do it the cheapest possible way... :)

Peter Pan wrote:
> Lloyd E. Sponenburgh wrote:
>> "DTC" <no_spam@move_along_folks.foob> wrote in message
>> news:vibbi.19294$Ut6.18309@newsread1.news.pas.eart hlink.net...
>>> A real simple and low cost solution would be a Linksys WRT54G
>>> wireless router as your access point and a Linksys WAP54G Access
>>> Point in client mode at the other end would work fine.
>> Looking at the WRT54G (and already having a WAP54G), I note there's no
>> external antenna connections on these.
>>
>> I'm reasonably competent at hacking into and attaching connectors to
>> things that shouldn't have them. Is this the route(r) to take to
>> attaching the directional antennae?
>>
>> I know this one will sound stupid, but here goes.... there are two
>> omnis on each unit now. Do they get replaced with two
>> differently-polarized directional arrays, or is one antenna
>> sufficient for each unit?
>> Thanks,
>> LLoyd
>
> Just to confuse you even more, while it has two omnis on it, they are not
> equal or split.... the antennas are actually BOTH alternataly switched and
> alternate which is active, so you can't do just one.... If you do something
> with just one, you are screwed....... (as per your q above, yes, TWO
> directional arrays, or tap into the signal before the splitter/switcher and
> just have one.....(have no idea where that may be, but others can give you
> tech details)
>
>
you can actually turn off either antenna in the software, and it will
work just as well as if both were on. It is just BS that you will be
screwed by using one antenna.

David wrote:
> Peter Pan wrote:
>> Lloyd E. Sponenburgh wrote:
>>> "DTC" <no_spam@move_along_folks.foob> wrote in message
>>> news:vibbi.19294$Ut6.18309@newsread1.news.pas.eart hlink.net...
>>>> A real simple and low cost solution would be a Linksys WRT54G
>>>> wireless router as your access point and a Linksys WAP54G Access
>>>> Point in client mode at the other end would work fine.
>>> Looking at the WRT54G (and already having a WAP54G), I note there's
>>> no external antenna connections on these.
>>>
>>> I'm reasonably competent at hacking into and attaching connectors to
>>> things that shouldn't have them. Is this the route(r) to take to
>>> attaching the directional antennae?
>>>
>>> I know this one will sound stupid, but here goes.... there are two
>>> omnis on each unit now. Do they get replaced with two
>>> differently-polarized directional arrays, or is one antenna
>>> sufficient for each unit?
>>> Thanks,
>>> LLoyd
>>
>> Just to confuse you even more, while it has two omnis on it, they
>> are not equal or split.... the antennas are actually BOTH
>> alternataly switched and alternate which is active, so you can't do
>> just one.... If you do something with just one, you are
>> screwed....... (as per your q above, yes, TWO directional arrays, or
>> tap into the signal before the splitter/switcher and just have
>> one.....(have no idea where that may be, but others can give you
>> tech details)
> you can actually turn off either antenna in the software, and it will
> work just as well as if both were on. It is just BS that you will be
> screwed by using one antenna.

Point is you have to turn one OFF, if you leave it on both, and disconnect
one and wire an external antenna to the other, you will mess things up and
be beyond screwed :)

On Mon, 11 Jun 2007 16:26:09 -0700, David <youcantoo@findmoore.net>
wrote:

>you can actually turn off either antenna in the software, and it will
>work just as well as if both were on. It is just BS that you will be
>screwed by using one antenna.

I beg to differ. Diversity reception is a big win if you have a
highly reflective environment, such as a typical house or office. You
can get along without diversity, as there are plenty of access points
with just one antenna, but you will find that as you move around,
there will be more spots with deep fades. The problem is called
"frequency selective fading". That's where two paths between the
transmitter and receiver are exactly 180 degrees otto phase and
cancel. With diversity, that happens much less. The improvement is
much more with 802.11b than with 802.11g. ODFM (802.11g) divides the
22MHz of occupied bandwidth into a mess of independent carriers, each
of which carries a part of the signal. The receiver recombines all
these carriers to reproduce the original data. If one of these
disappears, the thruput only slows down a little, but does not
disappear. Since frequency selective fading will affect only one of
these carriers at a time, ODFM is far more resiliant to multipath
problems than 802.11b modulation methods.




--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

On Mon, 11 Jun 2007 21:00:11 -0400, "Peter Pan"
<PeterPanNOSPAM@AkamailNOSPAM.com> wrote:

>Point is you have to turn one OFF, if you leave it on both, and disconnect
>one and wire an external antenna to the other, you will mess things up and
>be beyond screwed :)

Yep. Actually, having two different types of antennas can cause
problems. See the golf course case study in the Cisco article below:
<http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a008019f646.shtml>
<http://www.eetimes.com/showArticle.jhtml;articleID=16501888>
<http://www.commsdesign.com/showArticle.jhtml;articleID=16500279>

There were also some really nasty problems trying to use the two
diversity antennas as a store and forward repeater between two
clients. Typically, someone would run one stock rubber ducky antenna,
and one external outside antenna for the neighbors. The diversity
switch logic just didn't want to switch back and forth for each packet
quickly enough. The result was incredibly slow thruput. This has
been largely fixed with faster processors, but is still a problem at
high speeds. However, it would work just fine for either client
accessing the internet. It's just client to client that would be very
very very slow.


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

Jeff Liebermann wrote:
> On Mon, 11 Jun 2007 16:26:09 -0700, David <youcantoo@findmoore.net>
> wrote:
>
>> you can actually turn off either antenna in the software, and it will
>> work just as well as if both were on. It is just BS that you will be
>> screwed by using one antenna.
>
> I beg to differ. Diversity reception is a big win if you have a
> highly reflective environment, such as a typical house or office. You
> can get along without diversity, as there are plenty of access points
> with just one antenna, but you will find that as you move around,
> there will be more spots with deep fades. The problem is called
> "frequency selective fading". That's where two paths between the
> transmitter and receiver are exactly 180 degrees otto phase and
> cancel. With diversity, that happens much less. The improvement is
> much more with 802.11b than with 802.11g. ODFM (802.11g) divides the
> 22MHz of occupied bandwidth into a mess of independent carriers, each
> of which carries a part of the signal. The receiver recombines all
> these carriers to reproduce the original data. If one of these
> disappears, the thruput only slows down a little, but does not
> disappear. Since frequency selective fading will affect only one of
> these carriers at a time, ODFM is far more resiliant to multipath
> problems than 802.11b modulation methods.
>

Jeff,

Thanks for pointing out my errors!

On Mon, 11 Jun 2007 21:40:12 -0700, David <youcantoo@findmoore.net>
wrote:

>Jeff,
> Thanks for pointing out my errors!

Sure, but it's not really your error. The problem is that there are
too many things going on with diversity more most people to understand
how it really works. I posted 3 URL's in another article in this
thread that explains things in detail. It's easy enough to see how
you came to your conclusion. Many manufacturers have gone from two
antennas to just one in an effort to cut costs. For example, the
various mutations of the DLink DI-624, DI-614+, and others come in one
and two antenna versions. However, lately, the manufacturers have
returned to two antenna products. That's because the average consumer
seems to equate the number of antennas with some kind of performance
improvement. That's true for 802.11b, but not so much for 802.11a/g.
Two antennas sells better, so two antennas are what is supplied.

Also, you can get into trouble if you just remove one antenna, but not
disable it in the firmware. I seem to have created the problem in my
home WRT54GSv4. The diversity switch logic is set to favor one of the
two antennas. Which port varies depending on model and chipset (and I
forgot which one mine favors). It sits on the "main" antenna and only
switches to the "aux" antenna if the BER (bit error rate) on the
"main" antenna is higher than acceptable. If I do something dumb like
connect a real antenna to the "aux" antenna, disconnect the "main"
antenna, and NOT disable the port in the firmware, the system will
still favor the "main" antenna, which is sitting there with nothing to
hear. The system does *NOT* scan between antennas (as some early
implementations did). It assumes equal antennas on both ports and
therefore sits on the "main" port waiting to receive something.
However, if there's no antenna on the main port, there's nothing to
receive, so it doesn't know that it should switch to the "aux" port.
The result is no connection at all. I had no idea what was going on
and chased all manner of wild geese until I stuck an oscilloscope on
the diversity PIN switch and figured out what it was doing. If I get
time, I'll post waveforms and tests. This diversity thing is way more
complex than it initially appeared. Incidentally, MiniPCI cards are
labeled "Main" and "Aux" on the two antenna ports.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558 jeffl@comix.santa-cruz.ca.us
# http://802.11junk.com jeffl@cruzio.com
# http://www.LearnByDestroying.com AE6KS

"Peter Pan" <PeterPanNOSPAM@AkamailNOSPAM.com> wrote in message
news:nYCdnbjQ144GXPDbnZ2dnUVZ_i2dnZ2d@comcast.com. ..
> Lloyd E. Sponenburgh wrote:
> > "Peter Pan" <PeterPanNOSPAM@AkamailNOSPAM.com> wrote in message
> > news:gMSdnbwJc-PR5vDbnZ2dnUVZ_hynnZ2d@comcast.com...
> >> What is 10 Base-T?
> >>
> >> 10Base-T --- standard configuration that allows construction of 10
> >> Mbps ethernet LANs over unshielded twisted-pair wire.
> >>
> >>
> >> Under 10 Base-T, workstations are cabled using twisted-pair wire to
> >> medium access units (MAUs). Each MAU normally has a built-in
> >> attachment interface unit (AIU) that can be cabled to a coaxial
> >> transceiver attached to a coaxial cable. Thus, workstations can be
> >> configured in a star topology and cabled to a bus structured
> >> backbone cable that serves to interconnect MAUs.
> >
> > Yep, thanks. I know all that. A Looooong time ago in a land far
> > away, I was a networking supervisor, long before WIFI was even an
> > itch. I'm even half-way tempted to try a hank of OSP, direct-burial
> > cat5e over the 400' just to see if it can wheedle out a useful 5mbs
> > without too many retries to be useful.

400 ft is only 130m - the standards have a fair bit of "slack" in them so
even 100 Base-Tx has got a fighting chance.

there are some alternatives, designed to run "ethernet" over phone quality
copper - 1 example (that i havent tried, so buyer beware)
http://www.bb-europe.com/product_fam...348&s=INEE0607

30 Mbps claimed at 600m.....

speed / distance sounds like VHDL or similar - and it looks like it is
designed for industrial use, so you are probably paying for the packaging to
some extent.

But then, I'd sort of be
> > comitting myself to hard-wired... and I'd like to do this with a
> > 'new' technology, if it's reasonably inexpensive, and still reliable
> > in the malicious weather we have in Florida in the summer.
> >
> > My last 'real' install was in 1999; gigabit fiber in a government hub
> > in some unnamed Southern US city.
> >
> > (No, I don't have cleaving and termination tools anymore, so fiber is
> > out -- costy, anyway)
> >
> > LLoyd
>
> Point was to use what you have.. You said you already had an abandoned
phone
> line (twisted pair), running between the buldings, and wanted something
> faster than your current 1.5 DSL (hence 2base t), and faster than a new
DSL
> at 6 Mbps speed (hence the 10 base t)... As I recall from when I did that,
a
> few years ago, on an old phone line to my garage, got the devices off ebay
> for about $20 (old star net stuff)... In place of the MAU's on the above,
> used WRT (Wap router) both inside and in the outbuilding which gave me
both
> wired and wireless in both places (Linksys WRT54G at walmart for $48)..
Did
> it both in Idaho and Tampa FL area (foliage growing, and bad weather,
really
> screwed up wireless outside) I'm guessing that since you aren't the
> government, you probably want to do it the cheapest possible way... :)
>
--
Regards

stephen_hope@xyzworld.com - replace xyz with ntl

1) Diversity antennas: (Correct me if I'm wrong, Jeff!)

Linksys diversity means that if the signal comes in stronger on
antenna A, then it goes out on A. If reception is better on B, then
it goes out on B. The golf course study is checking out the idea of
pointing each antenna in a different direction. Problem is, if it
comes in direction A strong, then B direction is supposed to receive
something, it's going out on A. In sum problem is not having one
antenna disabled (or possibly just removed ) on a diversity system,
it's having two antennas pointed in different directions with
different clients competing for direction.

So my conclusion and advice I've seen in other places is: just remove
the second antenna and use only one for a hi-gain antenna. If you can
turn it off in the firmware, all the better. I have a linksys
working that way right now. No problems at all.

I suppose if somebody came along in just the right place (single hi-
gain antenna's dead spot) and connected to the router via the (weak
but probably more omni/isometric) antenna-less side, it could screw
things up, but I'm using mine like you would, as a bridge. It's
only connected to one thing.

2) You can use the phone lines for your signal and Jeff knows what
those adapters are called. Not expensive, IIRC.

3) You can run ethernet 400 feet without a problem. Not that far out
of bounds as the technical limit is 100 meters. It may or may not do
full speed, but you'll be fine if it defaults to 10. I've got one at
120 meters. I forget if it connects at 100 or 10. I know somebody
thate ran one over 200 meters.

4) Powerline is good option too. Well worth considering.

In sum, every solution will work. What's easiest (phone or
powerline), cheapest (phone or powerline), most reliable (not wifi).
You weigh it out.

Steve

PS. Where you on SAT before?

seaweedsteve <seaweedsteve@gmail.com> hath wroth:

>1) Diversity antennas: (Correct me if I'm wrong, Jeff!)

Sigh. Lots wrong.

>Linksys diversity means that if the signal comes in stronger on
>antenna A, then it goes out on A.

Not Linksys, but varies with chipset and chipset manufactory. There
are many different algorithms (most of them patented). There were
some early models that would use diversity receive, but always
transmit on the same "main" antenna. It's not a great way to do it,
but there's not much benifit to "diversity transmit", especially if
the wireless client has diversity receive capeabilities. Most PCMCIA
cards have diversity. Most USB dongles don't have the space for two
antennas and therefore do not.

>If reception is better on B, then
>it goes out on B.

Not exactly. Reception isn't a measure of anything useful. Many
people assume that the selection is made by signal strength. It's
not. It's by error rate. What the diversity switch is looking for
are symptoms of frequency selective fading. That's usually in the
form of totally trashed packets. The incident and reflected signals
arrive 180 degrees out of phase and cancel. If they don't exactly
cancel, they trash each other. Either way, the decoded packets show
up as garbage. If enough corrupted packets arrive this manner, it's a
fair assumption that the RF path is screwed up and that perhaps this
would be a great time to try the other antenna.

Here's the part I'm not sure about. The diversity switch apparently
does NOT stay on the "aux" antenna for very long. If the "aux"
antenna works better than "main", it will continue to use the "aux"
antenna until something convinces the diversity switch to go back to
the "main" antenna. I haven't had time to figure out what that
something is. My guess is that it's just a timeout. After so much
time of no data, my guess(tm) is that it reverts back to the "main"
antenna.

>The golf course study is checking out the idea of
>pointing each antenna in a different direction.

Yep. It's a common idea. I've even (wrongly) recommended such an
arrangement. It doesn't work too well. The diversity switch cannot
be used as a store and forward system. It will not switch between the
"main" and "aux" antennas fast enough, or often enough (for each
packet) to be usable. There's also a real possibility with two
radically different antennas, that the diversity switch will settle on
the worst antenna and stay there.

>Problem is, if it
>comes in direction A strong, then B direction is supposed to receive
>something, it's going out on A. In sum problem is not having one
>antenna disabled (or possibly just removed ) on a diversity system,
>it's having two antennas pointed in different directions with
>different clients competing for direction.

Exactly. If the switch could switch antennas for each packet, that
will work. But it can't.

>So my conclusion and advice I've seen in other places is: just remove
>the second antenna and use only one for a hi-gain antenna. If you can
>turn it off in the firmware, all the better. I have a linksys
>working that way right now. No problems at all.

Yep, same here. I sometimes suggest terminating the unused antenna,
but that's optional, especially if you can turn off the unused antenna
in the configuration pages.

>I suppose if somebody came along in just the right place (single hi-
>gain antenna's dead spot) and connected to the router via the (weak
>but probably more omni/isometric) antenna-less side, it could screw
>things up, but I'm using mine like you would, as a bridge. It's
>only connected to one thing.

Yeah, it's possible, but improbable.

Incidentally, there are proprietary and non-standard systems that do
spacial and frequency diversity available. See Mikrotic Nstreme2:
<http://www.mikrotik.com/wireless.php#nstrm>
which uses two pairs of radios at each end, with seperate tx and rx
antennas.

>2) You can use the phone lines for your signal and Jeff knows what
>those adapters are called. Not expensive, IIRC.

Ummmm... perhaps "phone line networking"?
<http://www.homePNA.org>
<http://www.homepna.com>

>3) You can run ethernet 400 feet without a problem. Not that far out
>of bounds as the technical limit is 100 meters. It may or may not do
>full speed, but you'll be fine if it defaults to 10. I've got one at
>120 meters. I forget if it connects at 100 or 10. I know somebody
>thate ran one over 200 meters.

That was me again. I haven't done much with extending 100BaseTX
mostly because every time I try to go much over about 500ft, it screws
up with lots of collisions. However, 10baseT-HDX is no problem up to
at least 1000ft. I commonly attach RJ-45 plugs on the ends of a new
roll of CAT5e cable for testing. Works fine. My longest installed
run is 900ft.

I also use either RG-58a/u or RG-6/u (75 ohm) coax cable and 10base2
networking. I have one 1200ft link running CATV coax this way.

The price of fiber and fiber media converters is down to the point
where using fiber optic cables are an option.

Power Line networking:
<http://www.homeplug.com>

Phone line networking:
<http://www.homepna.com>
<http://www.homepna.org>

CATV coax sharing:
<http://www.coaxsys.com>
<http://www.multilet.com>
<http://www.mocalliance.org>

Ethernet extenders:
<http://www.patton.com/products/pe_products.asp?category=146>
(there are others)

>4) Powerline is good option too. Well worth considering.
>
>In sum, every solution will work. What's easiest (phone or
>powerline), cheapest (phone or powerline), most reliable (not wifi).

Yep. Wireless has many advantages, but reliability is not one of
them. One leaky microwave oven can take out the whole neighbhorhood.

>You weigh it out.

Mass, not weight. You mass it out.

>Steve
>
>PS. Where you on SAT before?

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:

> Here's the part I'm not sure about. The diversity switch apparently
> does NOT stay on the "aux" antenna for very long. If the "aux"
> antenna works better than "main", it will continue to use the "aux"
> antenna until something convinces the diversity switch to go back to
> the "main" antenna. I haven't had time to figure out what that
> something is. My guess is that it's just a timeout. After so much
> time of no data, my guess(tm) is that it reverts back to the "main"
> antenna.
>

I came across this about a year ago, on the testing of multiple antenna
devices. Part of the conclusion was "A concept as simple as diversity
switching, which introduces the behavior of a software algorithm into
what would normally be a simple RF problem, can result in unexpected and
blatantly erroneous results".
http://rfdesign.com/mag/602RFDF4.pdf

kev <invalid@invalid.invalid> hath wroth:

>Jeff Liebermann wrote:
>
>> Here's the part I'm not sure about. The diversity switch apparently
>> does NOT stay on the "aux" antenna for very long. If the "aux"
>> antenna works better than "main", it will continue to use the "aux"
>> antenna until something convinces the diversity switch to go back to
>> the "main" antenna. I haven't had time to figure out what that
>> something is. My guess is that it's just a timeout. After so much
>> time of no data, my guess(tm) is that it reverts back to the "main"
>> antenna.

>I came across this about a year ago, on the testing of multiple antenna
>devices. Part of the conclusion was "A concept as simple as diversity
>switching, which introduces the behavior of a software algorithm into
>what would normally be a simple RF problem, can result in unexpected and
>blatantly erroneous results".
>http://rfdesign.com/mag/602RFDF4.pdf

Nice article. The author is chair of the 802.11 group dealing with
cellular and wi-fi conglomeration. That may actually happen, but not
as long as cellular service providers continue to block the inclusion
of wi-fi and other useful non-cellular features in their subsidized
phones. In the US, something like 95% of the phones are purchased
from the cellular providers. That's not the case in Europe, where I
would expect to see more complicated conglomerations.

The author seems primarily concerned about polarization diversity.
That's because antenna pattern switching diversity (spatial diversity)
is near useless in a handset that's not large enough to provide
adequate antenna separation. It's also not all that important with
somewhat frequency selective fading immune multi-carrier OFDM systems
(CDMA) as it is with TDMA systems (GSM). Polarization diversity
antennas also take less spatial diversity.

The article also neglects the wi-fi related questions brought up in
this thread, such as how important is receive diversity, and how duz
it work? My opinion, based on substantial guesswork and limited
access to internals, is that for OFDM, in a moveable environment, it's
of marginal. For fixed PtP links, where the fade margin is
inadequate, it's vital. For 802.11b modes, that lack multi-carrier
modulation advantages for reducing frequency selective fading,
diversity is very useful but not vital. My guess(tm) is that you
could turn off diversity in most situations and never notice much
difference, except perhaps in highly reflective environments.

As for implementation, I'm lost. What I read in the patents and what
I see in my tinkering, often do not agree or make sense. I attached
some wires to the diversity switch on my WRT54G (Broadcom) and ended
up totally confused as to how it works. I had a difficult time
intentionally getting the logic to switch from the "main" to the "aux"
antenna, and could not reliably induce switching. Little wonder the
designers haven't added flashing LED's on each antenna so the users
can see the action. There was no action to see as it sat on the
"main" antenna for most of my testing. More tinkering is required and
I'm out of time (and bench space).

Diverse reading:
<http://www.commsdesign.com/showArticle.jhtml;articleID=16500279>
<http://www.eetimes.com/showArticle.jhtml;articleID=16501888>
<http://www.eetimes.com/showArticle.jhtml;jsessionid=0C2WHPCA5PNXWQSNDLOSK H0CJUNN2JVN?articleID=16501888>
<http://www.google.com/patents?q=diversity+switched+antenna&btnG=Search+P atents>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Jeff Liebermann wrote:

> As for implementation, I'm lost. What I read in the patents and what
> I see in my tinkering, often do not agree or make sense. I attached
> some wires to the diversity switch on my WRT54G (Broadcom) and ended
> up totally confused as to how it works. I had a difficult time
> intentionally getting the logic to switch from the "main" to the "aux"
> antenna, and could not reliably induce switching. Little wonder the
> designers haven't added flashing LED's on each antenna so the users
> can see the action. There was no action to see as it sat on the
> "main" antenna for most of my testing. More tinkering is required and
> I'm out of time (and bench space).
>
I have just been having a look at the HWB1151, that Frank was enquiring
about drivers for, Data Sheet and it's yet another one depending on the
algorithm written for it, although it only checks the signal during
preamble.

"In the receive mode, the radio signal is received by one of
the two external antennas. The antenna selected is optionally
determined by an Antenna Diversity algorithm in the Baseband
Processor which compares the quality of the received signal
in each antenna during the Preamble and selects the better signal
.. This substantially improves the multipath performance of the
assembly. Alternately, the antenna selection may be directly
controlled by the software"
http://www.nalanda.nitc.ac.in/indust...sil/an9835.pdf
> Diverse reading:
> <http://www.commsdesign.com/showArticle.jhtml;articleID=16500279>

I get a blank page.
> <http://www.eetimes.com/showArticle.jhtml;articleID=16501888>
Says article no longer available.
> <http://www.eetimes.com/showArticle.jhtml;jsessionid=0C2WHPCA5PNXWQSNDLOSK H0CJUNN2JVN?articleID=16501888>
> <http://www.google.com/patents?q=diversity+switched+antenna&btnG=Search+P atents>
>
Slowly looking.

>

kev <invalid@invalid.invalid> hath wroth:

>I have just been having a look at the HWB1151, that Frank was enquiring
>about drivers for, Data Sheet and it's yet another one depending on the
>algorithm written for it, although it only checks the signal during
>preamble.
>
>"In the receive mode, the radio signal is received by one of
>the two external antennas. The antenna selected is optionally
>determined by an Antenna Diversity algorithm in the Baseband
>Processor which compares the quality of the received signal
> in each antenna during the Preamble and selects the better signal
>. This substantially improves the multipath performance of the
> assembly. Alternately, the antenna selection may be directly
> controlled by the software"
>http://www.nalanda.nitc.ac.in/indust...sil/an9835.pdf

It doesn't explain how the built in diversity algorithm works. I
suspect that I could dig through the various Harris/Intersil patents
and probably find something.

>> Diverse reading:
>> <http://www.commsdesign.com/showArticle.jhtml;articleID=16500279>
>
>I get a blank page.
>> <http://www.eetimes.com/showArticle.jhtml;articleID=16501888>
>Says article no longer available.
>> <http://www.eetimes.com/showArticle.jhtml;jsessionid=0C2WHPCA5PNXWQSNDLOSK H0CJUNN2JVN?articleID=16501888>
>> <http://www.google.com/patents?q=diversity+switched+antenna&btnG=Search+P atents>
>>
>Slowly looking.

Sigh. I always check the URL's before posting, but I cleverly tried
to trim off the session ID and probably broke something. Trying
again with the ID left intact:
<http://www.commsdesign.com/showArticle.jhtml;jsessionid=1EE5BBEG3LFU0QSNDLRCK HSCJUNN2JVN?articleID=16500279>
<http://www.eetimes.com/showArticle.jhtml;jsessionid=