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CC1101 range question

UMAMAHESH Y V
Intellectual 780 points
Other Parts Discussed in Thread: CC1101

What is the maximum range can CC1101 give.I need a tranceiver which give me 1km - 3 km distance

  • 0
    TI__Mastermind 29570 points

    Hi,

    You can achieve a range of several km with the CC1101 without any problems (line of sight). The output power can be programmed up to 12dBm and the sensitivity level on the receiver is dependent on the programmed baud rate. With a sensitivity of -112dBm and an output power of 12dBm, 915MHz ; the expected range with Friis equation adapted to take into account the height from the ground would be approx 3km.

  • 0 in reply to RGW
    Expert 1240 points

    3KM is theoretical, not practical. Very much depends on the antenna on both ends and the height above ground. Further, just finding a clear, flat test site over 1 mile long is a challenge. Also, although the radio may produce 12 dbm output, the radiated field strength may not be permissible in the US or Europe. Other factors include ambient RF noise as well as EMI coming from the microcontroller and other electronics.

  • 0 in reply to Zebryk
    TI__Mastermind 29570 points

    Hi Z,

    Good comments, I both agree and disagree at the same time :) 

    The distance of 3km (LOS) is practical but if this has to be guaranteed then the environment parameters will have to be reviewed thoroughly. Totally agree that the antenna choice and height above ground has a huge part to determine the overall distance. Also, any objects that  are in the LOS between the Rx and Tx unit will have to be compensated for the link budget. Calculating an accurate expected range is very difficult (near impossible) and every application has it's own parameters that have to be taken into account. No one can ever guarantee a specific range with a chipset because of these application specific parameters. Only a rough range guideline can be given.

    In order to make a practical link of 3km, then the worst case scenerios must be reviewed and taken into account when calculating the link budget. The maximum output that is possible is limited to the regulation requirements. At 915 MHz, FCC 15.247 states that the maximum carrier power should not exceed 30dBm and for FCC 15.249, 0dBm should not be exceeded.  

    A more practical approach would be to obtain the development kits and to test the units in the application environments that you are considering. What's nice with smart RF studio is that the radio parameters can easily be configured and then tested.

    Regards, Richard

  • 0
    Prodigy 150 points

    Hi UMAMAHESH.

    You can take a look at http://www.bit.it/Products/tabid/65/Default.aspx.

    Here you can find a transceiver based on CC1101 and a power amplifier with an output power up to +18 dBm.

    Both are available in 433 and 868 MHz frequency bands.

    Note that in the 433 MHz band you can deliver a maximum output power of +10 dBm,

    while in the 868 MHz max output power is higher.

    Hope this help.

    Best Regards.

    Bruno B.

     

  • 0 in reply to RGW
    Prodigy 80 points

    Hi Rich,

     

    I want to programmed to +12dBm. Could you tell me the hex value?

     

    Thanks

    Thomas

  • 0 in reply to Thomas Lan
    TI__Mastermind 21125 points

    Thomas, 

    From the datasheet Table 36 it looks like this value should be 0xC0.

    Rgds,
    Kjetil

     

  • 0 in reply to Kjetil
    Prodigy 80 points

    Thanks Kjetil

  • 0
    TI__Prodigy 700 points

    This range thing really had me going nuts a while back until I put some other information to the question. The question that needs to be asked is: what distance can I get with some specific error rate, and data rate? Also given that PSK is being used one needs a finite signal to noise gain in order to assue that error rate. The real noise floor happens to be the noise floor in your area along with your height and line of site limitations. It is very easy to lop off 30db+ of theoretical margin to get a practical link when one considers this and adds for fade and multipath. Once these adders are included realistic ranges begin to come from the equations. And datarate plays a part in that margin as well.

    It would be great to se a paper with all of these things taken into account and show the revised theoretical and the actual results.