Hi Paolo

First of all I think the the free  space model and two ray ground model
are dependent on antenna height and there is a crossover distance, after
which the model used is two ray ground. When you say you use free space
model, you must have the antennas to be very high, to acheive a free space
loss situation, otherwise two ray ground will take effect after the
crossover distance.  The default antenna heights, and transmit and recieve
frequency are shown below again with the Receiver Threshold value
(RXThresh). In your case you might have to increase the antenna height,
aslo change the receiver threshold aswell as increase the transmit power.

 freq  = 916e+6;
 RXThresh  =  3.66152e-10;
 ht = 1.5;               // transmit antenna height
 hr = 1.5;               // transmit antenna height

Now if I use the above settings for my simulation, the transmit power I
need to send a message 2010 m away is shown below

The transmit power is to be set to 1180.50

See if that helps,





>
> Hi all,
> i need to set up the range of my wireless nodes to 2000 m. I used the
> propagation.cc tool, with FreeSpace as propagation and 5.9e9 as frequency
> value, and it returnet a threshold value of 1.15361e-12 and a Pt value of
> 0.281838.
> I set up these values in my tcl script, but when a node transmit, not all
> nodes receive (all nodes are distant less than 2000 m from the
> transmitting
> node). In particular, only packets with power value greater than
> 1.630240e-11 will be received. Node farer from the source won't receive.
> Changing the threshold value and setting it lower doesn't affect this
> situation.
>
> Any ideas?
> Thank you very much for your attention.
> Bye.
>
> --
> Paolo Cencioni
>


Kind regards

Qasim Raza Iqbal
PhD Candidate,
ACNRG Lab N504,  Office N505
Adaptive Communications Networks Research Group,
School of Engineering And Applied Science
Aston University
Birmingham  B4 7ET
United Kingdom
http://www.ee.aston.ac.uk/research/acrg/index.html


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