Interference and routers

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I currently live in a 300 unit condo complex.  I'm running a netgear wgr614
router.  The router works fine in the morning and late at night.

My router overlooks my computers(I can see the attenae from my computer
chair).  The distance isn't very great maybe 15 feet.

However, I have problems with connectivity during primetime hours.  I kind
of think that I'm getting interference from my neighbors 2.4 ghz phones,
microwaves etc.  I really don't need the range just something that can work
with all the other devices going off.  I saw the Netgears ad for the
Rangemax router which says it does a better job with interference than
standard routers.  Would this actually help?  Is there a better wireless
solution besides moving ;P.



Re: Interference and routers



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Or from *their* wireless networks. A lot of people turn their wireless
routers on and off with their computers. Can you see any other SSIDs
during "primetime"?


Re: Interference and routers


ct wrote:
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Seriously, the best method to connect computers that are that close
together that would be immune to any other wireless devices would be to
us a couple of patch cables.

Re: Interference and routers



I can see other 2 other networks, but I have tried all the other channels
available to me, and still get interfernce.  I can usually see the other 2
networks 24-7.

I've run wired, but it really looks cheesy with blue wire running down the
stairs and going through the middle of the living room.



Re: Interference and routers


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You won't necessarily see the other networks (some people think
that hiding their SSID has security value, which is wrong but it
does result in their network not being obvious to people trying
to avoid interference).

Obviously there are any number of other sources of RF
interference at 2400MHz that you won't be able to "see".  It
could be any of them.

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Is it impossible to insert wiring into the walls?

Hmmm... this also doesn't fit the description of "15 feet" from
you original message???

If you have an AP and a client that are 15 feet apart and cannot
connect, I'm seriously suspicious that there is something wrong
with one or the other of the AP/client combination!

What kind of signal strength indications do you get (when they
are connected)?  At that distance is should be maximum, by
whatever measurement system you have.  (Probably -30 dBm to -40
dBm.)

Things that can cause problems are tower cases totally blocking
the little antennas.  And since the antenna is so close to the
case, the "block" can be in just about any direction (a
reflection off the case can cause phase cancellation of the
signal in the opposite direction, for example).  There is no one
simple cure for that, but you might try different antenna
orientations on both ends.  If all else fails, buy a short
"pigtail" of maybe 18" or so, and move the antenna away from the
case.

Also, if your equipment allows it, restricting the network to
less than maximum speeds might make it more reliable too.

As for covering two floors with one AP, that gets right into the
realm of "magic".  Horizontal polarization of your antennas
might be much better than vertical, just for starters.  First
that puts the main lobe of the pattern pointing up/down instead
of having a huge null there.  But another advantage is that if
you are getting interference from another wifi network they are
probably using vertical polarization, and by orienting your
antennas horizontally you'll decrease the signal from the other
network.

Going past that, if you are in any way a techie (you don't have
to be a radio tech, but you do have to get a kick out of doing
this kind of thing, or this is a no go idea), go buy a fairly
directional antenna, and experiment.  A $50 cantenna would do
it, but any antenna with good directional characteristics will
do the trick.  And that trick is to learn just *where* the
interference is coming from.  Since you can't see it, that won't
be so easy (unless you get a spectrum analyzer to hook up to the
antenna, and then it would be a snap).  But if you point your
antenna to the east and get no interference, then point is west
and do get interference...  you get the idea!  A little
triangulation and you can figure out where it comes from.

Once you know where it is, use directional antennas and relocate
your AP to a position where normal use means the interference is
in a direction perpendicular to a line between the AP and the
client.   Obviously in some circumstances that will work well,
and in others it may not work at all.

Another idea that is *really* out in "wierd's ville"...  If for
example you determine that all of the interference is coming
through one wall and originates in the adjacent apartment, it
might be possible to block it!  I'm not an interior decorator,
and can't tell you how to make something that would look good,
but I'm sure that a creative artist could.  But if that wall
were screened off with any kind of metal screening (chicken
wire, aluminum foil, whatever), it would do the job.  One
example would be to tack chicken wire to the entire wall and
then plaster it.  I'm sure there are creative people who could
design something suitable, but I'm a radio tech and not an
artist!

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

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It is just weird that I can receive perfectly during late night and early
mornings, then have a lot of disconnects between 4pm to 10:00pm.  My signal
strength goes from excellent to very good.  However, I've seen it drop to
fair to reconnect for short bursts of time during primetime.

My setup is a bit weird...during the hot summers I move my computers from
the upstairs loft, which has a window overlooking my living room, to my
living room.  I've set the router on the windowsill edge.

I'm just wondering if a more powerfull router setup might do the trick?



Re: Interference and routers


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The kicker is that time range!  Somebody somewhere near is
turning on something that interferes.  Hard to say what it is
though!

If the signal strength is "excellent" during the times when it
works, then your link isn't the problem.  If you were getting
just fair signal strength at best, then it might be your
radios/antennas/etc.  But that does not appear to be the case.

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Well, yes it might...  if you can increase the power of *both*
the AP and the client.  That isn't usually available though.
But better antennas would help, and that works even if you can
only do one or the other.

If you only have one client and it is stationary, so this is
essentially a point to point link (even if it gets moved now and
then), then directional antennas are probably the best solution.
If you can only do one, that might work too, but a directional
antenna for both the AP and the client would probably be useful.

The catch on that is a situation where the interference is in a
direct line with the two units.  In that case, only adding
directional antennas will do nothing, because the desired signal
might well be boosted but the undesired one gets exactly the
same boost.  If that happens, the only recourse is to move
either the AP or the client to change the direction of the line
between them so that it does not point at the source of
interference.  Then the directional antennas have an effect
because the desired signal is increased while the interferences
is reduced.

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

Re: Interference and routers



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The Netgear WGR614 wireless router comes in *FIVE* radically different
hardware versions.  Which version do you have?  See the serial number
label for clues.

See my comments on the WGR614 router at:

http://groups-beta.google.com/group/alt.internet.wireless/msg/7475da920b9a5446

http://groups-beta.google.com/group/alt.internet.wireless/msg/9561a6393a9f4b2e

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I think that means you are running some unspecified wireless clients
at a distance of 15 ft with no walls or obstructions in between.
Since the speculation is that you're getting some form of
interference, and since said interference can also affect the client
radios, could I trouble you to disclose some details on the client
radios?

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My prime time hours are about 10PM to 2AM PDT.  What are yours?
I a followup, you mention 4PM to 10PM.  That's way more than typical
prime time hours, which are usually designated at 7PM to 10PM.  Can we
try for numbers instead of generalities?

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That's interesting.  Do they "ALL" go off at the same time?  In the
same way?  At the same rate?  Do they come back by themselves at the
same time?  I'm trying to determine if the access point is being
affected, or if the individual unspecified client radios are being
affected.

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Maybe.  MIMO is generally a better technology than "ordinary"
802.11b/g.  However, I would like to concentrate on identifying the
cause and its source before offering hardware suggestions.  Of course,
you could just borrow a different wireless router and drag in a
friends known working laptop into the picture to see if any of your
existing hardware is defective or excessively susceptible to
interference.  That's what I like to do.  I have a know working access
point (not router) that I bounce around in my truck with me.  As an
access point, I can just plug it into someone's existing wireless
router into a LAN port, without any additional configuration, and have
it up and running in seconds.  That lets me do side by side tests
without forcing the customer to remember their DSL password, etc.
This access point also has a removable panel antenna which allows me
to test the effectiveness of different antennas.  There's nothing like
substitution testing to verify a suspected problem or culprit.

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Sure, but I don't have enough information.  There's too many things
inconsistent with your partial description to blame interference.
Let's go through the possible causes and see if they fit.

WISP and municipal Wireless networks - 24x7 interference.  May be
using all available channels, but usually not.  Can be avoided by
changing channels (1,6,11).

Microwave ovens - 1 to 10 minute runtime.  Only during meal times.
Clobbers all channels.

Cordless phones - 1 to 30 minute runtime.  Random hours.  Numerous
different frequency patterns.  Only a few clobber all channels and can
usually be avoided by changing channels.  Many tend to favor the lower
channels, so I would try channel 11.

2.4GHz video - 24x7 from security cameras or motion activated.  1 to
60 second interference times for motion detection.  Can be avoided by
changing channels.

Wireless TIVO - Follows TV hours but only on some days.  Can be
avoided by changing channels.

WiMAX, FHSS, Alvarion, HomeRF, etc - Clobbers all channels, all the
time.

There are plenty of others but these are the main culprits.  I don't
think any of the patterns follow your description.  You say that all
channels are affected, so that eliminates 802.11b/g based
interference, most types of cordless phones, and 2.4GHz video links.
The observation that the problem is NOT 24x7 eliminates WISP
installations, which tend to interfere all the time.  Do any of these
descriptions resemble the interference pattern you're seeing?

Actually, I think there is one device that very roughly fits your
pattern.  Inside house lighting.  I've found the little switching
power supplies that run the low voltage track lighting to be major
noise makers.  They have to be fairly close (10-50ft) to cause a
problem, but will do a great job of clobbering all channels.

Portable 2.4/5.7GHz portable spectrum analyzer:
  http://www.bantaminstruments.com
  http://www.bantaminstruments.com/425a_data_sheet.pdf
$2,600 for the 2.4Ghz only version.  $4,400 for the 2.4/5.7GHz.
I want, I want, I...(drool, drool, slobber)...want, I want...


--
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: Interference and routers


Well, the 4pm to 10pm was a guideline because it doesn't always happen at
exactly the same time or the same duration.  Most commonly it's 30 second to
1 minute outages, BUT on rare times times it can last for hours.

Maybe relavant,  my wife and I had purchased a pair of 2.4 ghz family
radios.  We were testing the range(5miles ya right).  There were another
person on the channel monitoring.  He did the verizon skit of can you hear
me now.  Could he be a ham radio operator interfering at times with the
signal?  At times our broadcast tv gets static.  I haven't noticed it it
coincided with wireless outages, because I only have the wireless hooked up
2-3 months in the year.

We live on a hillside.  We have live in a condo, which share a common wall
with 3 people(2 sides and a back wall....and does not include the neighbors
kittycorner or down below).



Re: Interference and routers



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Well 30 seconds to 1 minutes is close to the pattern for another
wireless access point that is being used intermittently, but
occassionally does large and long downloads.  This is pure guesswork
but might be a tolerable start.

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FRS radios are on 467Mhz and should not interfere (famous last
assumptions) with 2.4Ghz.  Certainly, the would not interfere for
hours as the battery would be long dead by then.

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Sigh.  I'm a ham operator, so be nice.  I can assure you that there
many more transmitters around that are not ham radio related.  Most
hams wouldn't touch FRS radios as they usually have better functioning
VHF/UHF handie talkies and mobiles.  I don't think it's FRS
intereference.

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Static usually means a loss of signal strength somewhere.  It can be
caused by the broadcast station if observed only on one channel.  If
all channels are affected, it can be caused by rotting connections,
intermittent cable, flakey amplifiers, and possibly by a nearby high
power transmitter blocking the receiver front end.  This is a real
possibility and could affect your 2.4GHz hardware in a similar way.
Any big commercial transmitters nearby (within about a mile radius)?

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I'm not sure what to suggest next.  Troubleshoot by substitution with
borrowed equipment as I previously suggested.

--
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: Interference and routers


On Sun, 17 Jul 2005 15:20:55 -0700, Jeff Liebermann

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Midrowave oven?
s

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Barry
=====
Home page
http://members.iinet.net.au/~barry.og

Re: Interference and routers



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No you didn't. Family radios work on 400 Mhz.

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No. 2.4 Ghz is ISM.

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Barry
=====
Home page
http://members.iinet.net.au/~barry.og

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