On 04/19/2011 05:44 PM, Gunther Ferdinand wrote:
Hi,
I would like to ask you a question regarding the USRP1 and WBX.
Have anybody made some tests with these and other ISM band
transceivers to see the communication distance indoor and outdoor? For
example if I have a tranceiver on 433MHz and it has a transmission
power of 17dBm, which should be the minimum distance in open air to be
able to receive data packets sent from the USRP1+WBX+LP0410, (what
about indoor - it depends from nr. of walls and thickness but anyway I
would like to know your opinion, and your experience with this)? Right
now I'm trying to make the packet (<PREAMBLE><SYNC><HEADER><DATA
LENGTH><DATA><CRC>) with the help of functions from Gnuradio, and it's
quite difficult, and then to make FSK modulation and send it to my
transceiver. In documentation for the USRP1 the transmission power is
between 50mW - 100 mW (17-20dBm)? For my transceiver that has 17dBm
transmission power says that it can transmitt data as far as 800m
outdoors, would it apply to USRP1, too? Indoors the transceivers works
quite well, I can send data from one module to other in my whole
house, the distance is around 15m, through walls (max. 3 walls between
transceivers). Anybody tried to do such kind of things, and has arived
to any results?
I would appriciate any comment on this.
Thank you very much,
Gunther.
Answering that question requires a lot of "it depends".
Maximum transmission distance is proportional to a number of parameters:
o transmit power (or more precisely effective radiated power
towards the receiver)
o receiver sensitivity--which depends both on noise figure of the
receiver, and directivity of the receive antenna
o any impairments to the signal due to physical obstructions,
causing absorption and multi-path reflections
o bandwidth of the signal
o modulation scheme
o processing gain due to coding techniques, etc
So, you see, a complete model is quite complicated, so answering the
question without "fleshing out the model" is not really possible.
Can you communicate beyond the edge of your desk? Yes, almost
certainly. Beyond the edge of your living room? Probably? Beyond the
edge of your city block? Not sure.
--
Marcus Leech
Principal Investigator
Shirleys Bay Radio Astronomy Consortium
http://www.sbrac.org
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