Re: [isp-wireless] Alvarion VL Problem

[Tom <tom@...>]

Look at the modulation errors on both ends for each link. (au and su)

The SA is not going to show Canopy and other new noise from 
non-802.11a gear in the area.  The mod errors will show the effects 
of that noise.

Since it was running fine for the past 4 years how are the 
signals?  (again check both ends)  Have they changed?  A weaker 
signal might show water in an antenna connection.  We have had extra 
rain this year in our area.

The problem that you are seeing is why we moved away from Alvarion VL 
and started using Mikrotik radios a couple of years ago.  Alvarion 
missed the boat.  And Mikrotik radios are a lot more flexible and a 
lot cheaper to install/repair.  i.e. I can go from 5.2GHz to 5.8GH 
with the same radio/antenna.  Repair cost after bad lightning might 
be $100-$200 instead of $4000.

Tom

At 06:48 PM 7/2/2008, you wrote:
> It has been running for 4 years.  Usuallay I have 2 frequencies to 
> play with.  Now both seem problematic.  (all seem problematic)
>
> Here is the SA from the AU.  Not sure how to interpret this.
>
> 5740    269    21    255    1
> 5750    364    23    237    216
> 5760    446    23    342    1
> 5770    343    21    255    0
> 5780     329    21    255    0
> 5790    405    22    254    0
> 5800    444    21    255    1
> 5810    238    21    255    0
> 5820    140    21    255    2
> 5830    40    20    255    60
>
> (5750 & 5830  is us on other links)
>
> The modulation levels are pretty much in the same area.
>
>
>
>
> > Was this running fine before or is this a new install?
> >
> > This is usually caused by interference.  You are dropping radio 
> > packets and retrying which causes the delays.  Look at the site 
> > surveys and check the modulation level errors.
> >
> > You need to fine tune your radios.  About all you can do is drop 
> > the max modulation level down on each device until they are mostly 
> > running without errors.
> >
> > Max modulation runs from 8 to 1.  We usually run cleanly around 4 
> > or 5 in our area.  Higher is better for speed but worse for noise 
> > immunity and signal level.  Lower is better for signal strength and 
> > noise immunity but less bandwidth available.
> >
> > This same concept is used on most OFDM based radios in use 
> > today.  We use it on Mikrotik, Alvarion, Redline in our network 
> > including 900, 2.4GHz, 4.9GHz, and 5.2 to 5.8GHz.  Learn it, 
> > understand it, and use it to your benefit.
> >
> > Good luck,
> >
> > Tom
> >
> > At 06:04 PM 7/2/2008, you wrote:
> > > I have an 5.8 AU that I have no problems pinging from the ethernet 
> > > side. However ping times across the AU to the SU's are all over the place.
> > >
> > > I tried several frequencies.  Same problem.
> > >
> > > It does not seem to care what time of the day it is.
> > >
> > > Any suggestions?
> > >
> > > Thanks in advance.



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> Attn: Discussion List Management
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>
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