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CC1101: CC1101 + LNA

Chris_CBC
Intellectual 470 points
Part Number: CC1101


I am running a CC1101 plus a LNA @ 433.92 MHz.  The modulation is MSK with a data rate of 250 kbps.

I am having trouble getting improved range from the receiver. If I measure with a signal source on the bench I can get -105.dBm sensitivity, but when I attach an antenna the radio doesn't get any more range and reports RSSI numbers similar to what it can do without the LNA.

Am I missing something here. I read another thread on this forum that suggested the same thing that I implemented. I just don't understand why it doesn't work better.   

   

  • 0
    TI__Guru**** 317180 points
    - Which sensitivity do you measure with a signal source on the bench if you measure on CC1101 without an LNA?
    - If I understand you correctly: You have two boards, one with CC1101 and one with CC1101 + LNA. You use the same test setup and antenna and measure the same range?

    If you see a 6 dB improvement on the sensitivity you should see 2x on the range.
  • 0 in reply to TER
    TI__Mastermind 39860 points
    What TER writes "If you see a 6 dB improvement on the sensitivity you should see 2x on the range." is correct if the sensitivity is not limited by the noise floor.

    Suggest you measure the noise floor in the field with 1) with the antenna connected and, if possible, 2) with the antenna disconnected and using a 50 ohm load the antenna feedpoint . Don't use a transmitter for this test. The sensitivity limit should be roughly 10 dB above the noise floor.