[Tinyos-help] Outdoor Range with Tmote sky

[Jacob Sorber]

You are asking for a simple answer where none exists.  Wireless channels are
tricky.  While line-of-sight is straightforward, "not in line of sight"
could mean a lot of things.  What is obstructing the signal?  A building?  A
person?  A hill of dirt and rock?  Is it raining?  What is the humidity?  I
have yet to find a radio that is immune to obstructions.  If you find one, I
would love to see it.  My experience has been that the 2.5Ghz radios are
usually more robust to obstructions than the CC1000 radios on the
Mica2/Mica2Dot motes, but not always.  When one mote is a meter under water
the CC1000 seems to do much better than the CC2420, though neither work very
well in that situation.  Also a rain storm can reduce the range some.  The
best thing to do is to program two motes and take them outside and see.  It
will only take a few minutes.  If you need a more technical explanation for
why node A can't hear node B, then you need to do some reading in the
wireless comm literature.  This might be a good place to start (
www.eecs.berkeley.edu/~dtse/cu_day1.ppt).

Hope that helps,

Jacob




On 2/6/07, manu suryavansh <suryavansh_manu at yahoo.co.in> wrote:
>
> hi,
> what is the range when not in line of sight, i thought that the
> communication in 2.5Ghz frequency range is not affected by line of sight
> thank you
> manu
>
> *Joe Polastre <joe at polastre.com>* wrote:
>
> As per the datasheet, 1 meter elevated above the ground, line of sight.
>
> For on the ground results, see:
> http://www.polastre.com/papers/spots05-telos.pdf
>
> -Joe
>
> On 2/6/07, Xavier Orduña wrote:
> > Hi,
> >
> > I'm using the tmote sky to deploy a wsn in an outdoor environment. After
> > firsts tests, I discovered that when motes are on the floor (without any
> > tripod or similar) the maximum range (using max tx power) is no higher
> > than 7 or 8 meters. That's very far from the 125 meter range that is
> > described in the tmote datasheet.
> >
> > Does anyone know what are the conditions in which the maximum range is
> > 125 meter in outdoor? Does anyone know if I'm doing something wrong (I'm
> > using the just unpacked Delta program and a little modification of Delta
> > to get sensor data)?
> >
> > Thanks a lot
> >
> > Xavi
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> >
>
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