OK Here is the Problem. How can I solve it?

Hi

I have recently bourght a narrowboat. The marina has a wifi connection
which I can get fine outside the boat. The boat is basically a long
squarish steel tube, with windows as an afterthought.

I can get a so so reception inside if I contort myself at a window, but
it is not ideal.

What I would like to do is put an external aerial out, and then have
some sort of way of putting that signal inside so I can roam within the
boat. There are no obstacles inside for the signal.

The PC I currently use is a laptop with IntedlPROset/wireless and would
like to retain this.

What are the options? In my mind I see an external aerial, linking
with coax to a wireless router, but I am sure it can't be that simple.

Over to you (please :-) )

Biggles

On 10 Jul 2006 12:50:59 -0700, in alt.internet.wireless , "Biggles"
<(E-Mail Removed)> wrote:

>Hi
>
>I have recently bourght a narrowboat. The marina has a wifi connection
>which I can get fine outside the boat. The boat is basically a long
>squarish steel tube, with windows as an afterthought.
>
>What I would like to do is put an external aerial out, and then have
>some sort of way of putting that signal inside so I can roam within the
>boat. There are no obstacles inside for the signal.

Simplest is to have a USB wireless dongle on a longish lead, you can
stick it outside the boat every time you need to use the 'net.

>The PC I currently use is a laptop with IntedlPROset/wireless and would
>like to retain this.

If you really want to do something like this you either need a unit
than can be in both client and AP mode simultaneously, or you need two
units, one in AP mode to service your laptop and one in client mode to
hook up to the boatyard WLAN. If you go this route, any AP with client
mode and detachable antennae will be fine, you can buy a matched
aerial from the same manufacturer in most cases.

--
Mark McIntyre

"Biggles" <(E-Mail Removed)> hath wroth:

>I have recently bourght a narrowboat. The marina has a wifi connection
>which I can get fine outside the boat. The boat is basically a long
>squarish steel tube, with windows as an afterthought.

A steel version of Noah's Ark. Cool. I like it.

>I can get a so so reception inside if I contort myself at a window, but
>it is not ideal.
>
>What I would like to do is put an external aerial out, and then have
>some sort of way of putting that signal inside so I can roam within the
>boat. There are no obstacles inside for the signal.
>
>The PC I currently use is a laptop with IntedlPROset/wireless and would
>like to retain this.
>
>What are the options? In my mind I see an external aerial, linking
>with coax to a wireless router, but I am sure it can't be that simple.

Mark McIntyre suggested a USB radio which is probably a good way to
go, especially if the marina has a strong wireless signal.

However, if you want to use the Intel ProSomething MiniPCI card in
your laptop, you can add a pigtail and external connector. It might
require drilling a hole or snaking the cable through an existing hole.
I found that I modem connector hole is sometimes plugged and can
easily handle a coax cable and connector.

You'll need a u-FL to SMA, TNC or N connector pigtail. See:
http://www.wlanparts.com/product/5210004-006
http://www.fab-corp.com/product.php?...cat=289&page=1
Attached to the cable or connetor would be an external antenna of some
sorts. I can't recommend anything specific without knowing something
about the signal strength, connector location on the vessel, and
approximate range required.

I don't think you're going to do much roaming around the boat with
either USB or a pigtail antenna connector. You're tethered by the
necessity of having an external connector, which is limited in both
length and ruggedness.

It may be possible to setup a passive or active repeater to get the
signal in and out of the vessel. I'm not a big fan of either, but
they do mostly work. Passive is always hurting for more signal.
Active store and forward repeaters (i.e. range extenders) have
compatibility and thruput problems.

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

Hi, Jeff, and group,

Jeff Liebermann wrote:
(snip)
>
> It may be possible to setup a passive or active repeater to get the
> signal in and out of the vessel. I'm not a big fan of either, but
> they do mostly work. Passive is always hurting for more signal.
> Active store and forward repeaters (i.e. range extenders) have
> compatibility and thruput problems.

Because I'm currently a pariah here, I refrained from jumping in at the
beginning.

This is exactly, without the mast, my project. Presumably, all the
ways I've been vociferously assured will work on my boat will work on
his. He just has a tougher hull to get 2.4G through, metals being more
challenging than fiberglass.

So, how come nobody's told him? Given that I manifestly have failed in
all of my attempts (I'm taking another run at it some time soon, making
another attempt at divide and conquer, simplify, simplify, etc.) thus
far, I'm obviously not the one to do it.

L8R

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

Biggles wrote:

> What I would like to do is put an external aerial out, and then have
> some sort of way of putting that signal inside so I can roam within the
> boat. There are no obstacles inside for the signal.
....
> What are the options? In my mind I see an external aerial, linking
> with coax to a wireless router, but I am sure it can't be that simple.

I do essentially this. I've been told it won't work, though :-)

I have a Linksys WRT54G router (which has dual antennas). One of the
standard antennas has been removed and connected to a coax cable to an
external antenna pointing at the house from which I get my Internet
connection (you'd probably just want an omni antenna). The router is
configured as a repeater (which would require, iirc, cooperation from the
marina people, as it needs to be configured at their end, too) The
remaining original antenna broadcasts to my home wireless clients.

Easier, and probably just as cheap, is to use a client-mode device (many
routers can be configured as clients) attached to the external antenna,
hardwired to an AP which will broadcast to the inside of the boat (on a
non-overlapping channel).
--
derek

Skip - Working on the boat wrote:

> Because I'm currently a pariah here, I refrained from jumping in at the
> beginning.
>
> This is exactly, without the mast, my project.

Perhaps I misunderstood your posts then, but I didn't see a requirement to
simply connect to your marina's wifi from a boat, but to be able to connect
to _any_ available signal. Connecting to a fixed signal for which you're
an expected user is pretty trivial unless you have distance issues.
--
derek

"Skip - Working on the boat" <(E-Mail Removed)> wrote:
>Because I'm currently a pariah here, I refrained from jumping in at the
>beginning.

I don't think you are a pariah, Skip, it's just that you were
thrashing so hard that I gave up trying to follow your constantly
morphing problem description, proposed solutions, and optimizations
thereof.

>So, how come nobody's told him? Given that I manifestly have failed in
>all of my attempts (I'm taking another run at it some time soon, making
>another attempt at divide and conquer, simplify, simplify, etc.) thus
>far, I'm obviously not the one to do it.

Nobody's told him what? That there are a bunch of different options?
That there are a half-dozen scattered threads on your subject?

On the contrary, you are our local expert on this subject, please jump
in and tell the OP what things you have tried and how well they
worked. Point him at the other threads. Pass along the helpful
advice you've gotten in this newsgroup.

"Biggles" <(E-Mail Removed)> wrote:
>There are no obstacles inside for the signal.

There are going to be serious multipath issues, so I'm voting for a
pair of WAP54G devices, one in client mode, one in AP mode on a
different non-overlapping channel.

"Skip - Working on the boat" <(E-Mail Removed)> hath wroth:

>> It may be possible to setup a passive or active repeater to get the
>> signal in and out of the vessel. I'm not a big fan of either, but
>> they do mostly work. Passive is always hurting for more signal.
>> Active store and forward repeaters (i.e. range extenders) have
>> compatibility and thruput problems.

>Because I'm currently a pariah here, I refrained from jumping in at the
>beginning.

You're not a pariah or whatever. My problem is that I don't think I
can solve your problems with your Senao 2611 radios. Your scheme
should have worked. If you have other questions (that don't involve
the Senao 2611 radios), I'll me more than happy to take a swing at
them (time permitting).

>This is exactly, without the mast, my project. Presumably, all the
>ways I've been vociferously assured will work on my boat will work on
>his. He just has a tougher hull to get 2.4G through, metals being more
>challenging than fiberglass.

No, your project was to get a single Senao 2611 to act as a proper
client adapter to your marina shared wi-fi. This is different.

Full Disclosure: I hate store and forward repeaters, mesh networks,
and range extenders. I consider them RF polluters because they
generate many duplicate packets in order to move just one packet.

Assuming that moving around inside the vessel hull is of paramount
importance[1], this is a tolerable application for a modified "range
extender". The problem is how to get adequate RF coverage both below
and above decks. The obvious way is to use two radios. A client
radio (WRT54G with DD-WRT v23 SP1 in client mode) on the outside. CAT5
and power through the hull. Any AP (access point) on the inside. This
is the way I used to play repeater before the "range extender" type
repeaters became available. One nice thing about it is that the two
radios can run on different channels thus avoiding mutual interference
and avoiding the inherent 50% slowdown.

However, 2 radios seems a bit like overkill. It should be possible
with one repeater[2] and two antennas. I have such a system at a
friends house. On the roof is an 8dBi omni antenna that is the main
site for a neighborhood LAN. 25ft of LMR-400 coax goes down into the
house where it connects to a 2 port splitter (power divider) as in:
http://www.hyperlinktech.com/web/sig..._2400_2way.php
I made my own, but these look nicer. The other port of the splitter
goes to an 8dBi panel antenna for in house coverage. The radio is a
Netgear something access point. The problem that this solved was that
with just the rooftop antenna, wireless coverage inside the house was
terrible. My friend didn't want to deal with two access points, or
package a radio for outdoor use. So, half the power goes to the
outside antenna, and half to the inside antenna.

Ignoring the coax cable losses, the transmit loss for each port is
3.5dB which will yield a 33% loss of range. Not good, but possibly
useable if the marina signal is strong. However, that's only in
transmit. In receive, the loss per port is only 0.5dB for a 6% loss
range. This is one place where an overly powerful xmitter (100mw or
more) is proper.

Note that this splitter system only works if the two antennas cannot
see each other. Were the antennas too close to each other, the
antenna patterns will interact resulting in odd nulls and peaks,
multipath effects, frequency selective nulls, and general weirdness.
Because the metal hull effectively isolates the two antennas, this
should be an ideal application.

The selection of the repeater is going to be a problem. Because
repeaters seem to be highly proprietary, manufactories test them
usually only with their own products. Compatibility issues are a
major problems. Even if they are able to function, timing problems
seem to cause problems with thruput and connection reliability. In
addition, some of the new and wonderful enhancements (Super-G,
Turbo-G, MIMO, etc) don't work with repeaters. All I can suggest is
not to buy anything that can't be tested and returned.

Please note that I haven't tried using a splitter and repeater in
combination on either land or water. Treat this as somewhat of an R&D
project. My suggestion would be to install a wireless client radio of
some sorts inside the hull. Run the coax through the hull and install
an outside antenna. Run CAT5 from the client radio to where the
laptop normally sits below decks. Nail the laptop to the table to
keep it from moving. Keep it simple.

>So, how come nobody's told him? Given that I manifestly have failed in
>all of my attempts (I'm taking another run at it some time soon, making
>another attempt at divide and conquer, simplify, simplify, etc.) thus
>far, I'm obviously not the one to do it.

The secret to successful engineering is to know when to give up.



[1] When I tried to type while underway, I got sea sick. Also,
moving around below decks carrying a laptop seems like a great way of
insuring that it will be dropped.

[2] For purposes of this discussion, the terms "repeater", "range
extender", and "store and forward repeater" are the same. I'm just
sloppy and tend to use the terms interchangeably.

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

Derek Broughton <(E-Mail Removed)> hath wroth:

>I do essentially this. I've been told it won't work, though :-)

It won't work(tm).

>I have a Linksys WRT54G router (which has dual antennas). One of the
>standard antennas has been removed and connected to a coax cable to an
>external antenna pointing at the house from which I get my Internet
>connection (you'd probably just want an omni antenna). The router is
>configured as a repeater (which would require, iirc, cooperation from the
>marina people, as it needs to be configured at their end, too) The
>remaining original antenna broadcasts to my home wireless clients.

The problem is the algorithm used by the diversity switch. It's not
like a VHF/UHF police scanner, that constantly scans for a signal.
It's a messy algorithm, that does it's best NOT to switch antennas
unless the signal is gone. The diversity switch simply will not
switch fast enough (or often enough) to play repeater, especially when
it has to switch on literally every packet.

If you wanna watch it fail with just an ordinary access point, try
setting up a test, where your access point or wireless router has two
highly directional antennas, preferably in separate rooms. Use AP
mode, not repeater mode. Place a wireless laptop in each room and try
to transfer data between the laptops. If there's some leakage between
rooms, reduce the AP xmit power, use attenuators, or longer coax
cables. The idea is to not have the laptops or antennas hear each
other.

I've done this test. It will sorta function but the thruput will be
awful and very bursty. The expected throughput should be 50% of the
connection rate if it were working as expected. I think I got about
2% to 5% of connection speed.

I recently found a nifty article on the different wireless diversity
systems. Unfortunately, I can't find it. Maybe later.

>Easier, and probably just as cheap, is to use a client-mode device (many
>routers can be configured as clients) attached to the external antenna,
>hardwired to an AP which will broadcast to the inside of the boat (on a
>non-overlapping channel).

Yep. That's exactly what I would suggest.

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