Router upstairs or down?

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If I want wireless coverage on both floors, where should the router be?
Upstairs or down?
Thanks
LT




Re: Router upstairs or down?



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The 'received wisdom' is that the higher the better. However, in the
case of a typical two-storey house with a wood/plasterboard first
floor, I doubt it makes any real difference.

Re: Router upstairs or down?


wrote:

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I have mine on the top floor and can receive a "good" signal 2 floors
down in the basement. Top floor, main floor, basement is the home
configuration.


Re: Router upstairs or down?


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It would probably be better off, as far as the radios alone are
concerned, if the AP was in the middle, on the main floor.  That
would be only one floor away from whatever you have on the top
floor or in the basement.  No path would require going through
two floors.

That said, radio paths are not the only consideration, and if it
works as is there is *no* point in changing it just for better
signals.

Another possible configuration, which should work just as well
as what you have, is to put the AP in the basement.  That has
exactly the same relative problems with radio paths as your
current setup, but it also has one other characteristic that
might (or not) be an advantage.  If the AP is in the basement it
will have less coverage horizontally away from your house.  In
other words the exposure to the neighbors is less.  That may
mean they can't crack into your network, or it may mean your
network won't interfere with theirs as much...  or it may do
nothing.

--
Floyd L. Davidson           <http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)                         floyd@barrow.com

Re: Router upstairs or down?


LT wrote:
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I find considerable success with the ap on the ceiling downstairs.

Re: Router upstairs or down?


Sounds like either floor works for me, since no neighbors and easy access
I'll  go up.  What about antenna orientation?  Should they (Linksys) be
horizontal or vertical for optimum floor penetration?
Thanks again
LT

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Re: Router upstairs or down?


LT wrote:
> Sounds like either floor works for me, since no neighbors and easy access
> I'll  go up.  What about antenna orientation?  Should they (Linksys) be
> horizontal or vertical for optimum floor penetration?
> Thanks again
> LT
>
>
>>LT wrote:
>>
>>>If I want wireless coverage on both floors, where should the router be?
>>>Upstairs or down?
>>>Thanks
>>>LT
>>
>>I find considerable success with the ap on the ceiling downstairs.
>
>
>
all the same , normally vertical . ( thats right angles to the earths
surface . :)


Re: Router upstairs or down?



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surely the orientation, vertical, horizontal diagonal matters not. After all
its only a signal.

I have mine horizontal, lower floor 5' from ground level and all seems fine.
The air vents are at the top for heat escape mind.

dj



Re: Router upstairs or down?


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Vertical is fine *if* the direction to all of your clients is
horizontal.  That isn't the case in a multi-floor building
though, so horizontal is almost guaranteed to be better for that
application.

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Oh, it matters!

First you've got the directional characteristics of the antenna
itself.  Perpendicular to the antenna is the best signal, and
directly off the ends there will be a null in the pattern that
might very easily approach 20 dB or even more.  That can simply
mean the difference between a nice solid connection with a -68
dBm signal strength, and an intermittant or non-existant
connection with a -88 dBm signal strength.

Then there is the matter of what is called polarization of the
signal.  Which is the relationship between the transmitting
antenna and the receiving antenna (assuming nothing in between
reflects the signal and changes its polarization).  There can
easily be 25 to 30 dB of difference!  So the two antennas should
at least start or default to the same orientation.  It's a good
idea to try moving the client antenna around a bit, because any
signal reflections off of metal objects will change the
polarization.  You might find 5 to 15 dB of extra signal that
way, just by tilting an antenna 30-60 degrees!

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Sounds good, and it works.

Radios are commonly accepted to work on the basis of FM.  FM, of
course, means Freaking Magic, or something close to that.
That's why you set them up the way their should work, and then
twist every knob and move everything you can, just to see what
happens.  They almost always work a little better once you've
misadjusted them!  (The trick is knowing *which* misadjustment
will improve things.)

--
Floyd L. Davidson           <http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)                         floyd@barrow.com

Re: Router upstairs or down?


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The radiation pattern for a typical omni-directional antenna
looks something like a fat doughnut with the antenna in the
center hole.  The doughnut represents signal strength, so the
more you go through, the better.

Straight off the ends of the antenna there is less signal, and
perpendicular to the antenna, all around the antenna, is best...
regardless of whether the antenna is vertical or horizontal.

If your antenna is vertical and sitting on the 2nd floor in the
center of the building, that means good coverage on that floor,
and poor coverage directly below it on the 1st floor but getting
better at locations on the 1st floor which are not directly
under it.

That is a bad location, generally, simply because there is no
way to orient the antenna and have it cover everywhere well.

Think about horizontal orientation and right up against an outer
wall.  The worst client locations then would be the two corners
off the ends of the antenna.

Or perhaps if the antenna is placed in a corner of the building,
with horizontal orientation and angled 45 degrees to the walls,
so that perpendicular to the antenna is a line straight to the
center of the building.  That one perhaps gives the best
coverage of all.

Of course if you have only two or three locations in the
building where you'll have a client, then you can optimize for
just those locations.

Also, if all else is equal, the client antenna should have the
same angle of orientation as the AP antenna.  However, things
are *never* equal...  reflections off any metal surface larger
that approximately 4" square will affect the polarization.  So
it's always a good idea, if the signal is anything less that
very good, to try moving the client antenna around a bit to
see if things can be improved with different angle.

--
Floyd L. Davidson           <http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)                         floyd@barrow.com

Re: Router upstairs or down?


Floyd L. Davidson wrote:
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So for a 2 antenna AP in a hard to get to loc (attic), how about setting
set one ant. vert and one horz? Seems like you would get the best coverage.

Re: Router upstairs or down?



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No, you want the antennas to be horizontal to each other. You have two
antennas for a reason. Signals are getting to the antenna at different times
and cancel each other out; that's why you have two antennas. They are there
for diversity.

Somebody please correct me if I'm wrong.



Re: Router upstairs or down?


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Yes.  That would be particularly beneficial if your clients
actually move around.  If you only a desktop, for example, which
stays in one place you can pretty much fool around and get
optimum results.  You only have to do it once and the benefits
last.  One antenna would be just fine.

But a laptop that is used just about anywhere you happen to be
at the moment is a different story.  You don't want to have to
fool with it each time you move.

The two antennas operate absolutely separate.  There is a
switch, and only one of antenna is connected at any given time.
The unit will periodically switch to see which antenna works
best, and then lock on that one antenna for that interval.
Which antenna to use is determined by the quality of the
received signal, and it just hopes that means the next transmit
operation will also be best on that antenna.

If everything stays the same it means that if there is only one
Client connected to the AP, it will probably spend virtually all
of the time connected to one antenna.  If there are two or more
Clients, or if the one Client moves, or if anything affects the
signal path (for example, someone opens the refrigerator door...
and that just happens to provide a better path for the "other"
antenna), then it will be switching.

But in some cases it will switch to the antenna best for one
client and instead transmit to another client that would have
been better with the other antenna.

So it is not perfect, but is probably a significant overall
improvement.

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Except they *don't* cancel each other out, because only one
antenna is connected at any given time.  That means that if one
is horizontal and one is vertical, you can change the
polarization of the signal from the Client and it will cause the
AP to switch antennas to get the best signal.

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Diversity is indeed what it is.  But diversity requires some way
to switch to which ever is better, based on some difference that
can be detected.  There are *many* different diversity systems,
all of which fit some but not all circumstances.  For example,
the system used by 802.11 wireless radios works well only because
the data consists of digital packets that can be stored and retransmitted,
even out of order, if errors happen.  That is one of the reasons that
while the maximum data rate might well be 54Gb, you are never going to
get throughput approaching that rate.

--
Floyd L. Davidson           <http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)                         floyd@barrow.com

Re: Router upstairs or down?


On Thu, 05 May 2005 21:28:13 -0800, floyd@barrow.com (Floyd L.
Davidson) wrote:

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Reflections can kill the S/N ratio and pollute the data stream with
inter-symbol interference.  OFDM is very good at recovering from this
kind of multi-path (reflection) interference, but not with a very weak
signal.  You can approach the problem of in-building coverage two
ways:
1.  A whopping strong signal and use OFDM to recover from the
reflections.
2.  An antenna and polarization insensitive configuration with fewer
reflections, but less signal strength.

The first is easy.  Disable 802.11b and set the access point to
802.11g.  Even at the slowest connection speed (6Mbits/sec), OFDM is
much better than CCK at dealing with bouncing signals.

The 2nd method required circular polarized antennas.  It can be right
and or left hand sense.  The clients still run vertical or horizontal
polarization, but the access point doesn't care which one arrives.
The catch is that there is a -3dB cross polarization loss which
reduces the signal strength somewhat.  Considering that the deep fades
caused by multipath cancellation and cross polarization are *MUCH*
larger than -3dB, methinks this is a good tradeoff.

I haven't done any testing with circular polarized access point
antennas at 2.4Ghz.  However, I once did quite a bit with 440MHz ham
repeaters and 850Mhz cellular on mountain tops.  Raleigh fading causes
the signal to get "chopped" as a vehicle moved through the multipath
cancellation nulls.  It was also called "picket fencing".  Replacing
the conventional vertically polarized antennas with circular polarized
antennas on the repeater or cell site drastically reduced the picket
fencing with only a slight reduction in range.  Most FM broadcast
stations have been using either circular polarization, or split their
signal between horizontal and vertical polarized radiation to
accomidate home users with horizontal antennas, and moving mobiles
with vertical whip antennas.  The PCS cellular providers are also
mixing the polarization to accomidate handsets with hidden internal
antennas, which are horizontally polarized.  It's not like circular
and mixed polarization is something new.

Trying to get reliable coverage through multiple floors is a waste of
time.  It may work but it's not going to be consistent, stable, or
reliable.  Almost all the signal between floors is the result of a
bounce off of something, which tends to be unstable.  The signal
usually appears miraculously at the distant end of the house, but
disappears when something is moved or changed.  The result is constant
repositioning of the antennas which can get irritating rapidly.  If
you want reliable coverage of multiple floors, use multiple access
points on each floor with a wired backbone.  If you're cheap, run coax
from the 2nd antenna on the access point to the floor above or below
to another antenna.

Drivel:  One of my friends claimed his access point would go through 3
concrete floors in a college dorm.  A bit of direction finding
demonstrated that the bulk of the useable signal was bouncing off the
adjacent building and not going direct through the floor.  Of course,
the bounce path was not very reliable.


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

Re: Router upstairs or down?


On Fri, 06 May 2005 08:51:15 -0700, Jeff Liebermann

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I guess I haven't been paying attention.  
Circular polarized 2.4GHz antennas:
  http://www.hyperlinktech.com/web/hg2409pc.php
  http://www.turbowave.com/solutions/Antennas.html
  http://www.wlanantennas.com/patch_antenna_2405.htm

I dunno about this antenna that claims to be "multi-polarized".
  http://www.wifi-plus.com
  http://www.connectronics.com/wifi_plus /

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice  http://www.LearnByDestroying.com
#                         jeffl@comix.santa-cruz.ca.us
#                           jeffl@cruzio.com     AE6KS

Re: Router upstairs or down?



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Downstairs high up on a table or upstairs on the floor.



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