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CC2500 range

Chandrashekar N B
Prodigy 120 points 
we have cc2500 in our hardware for wireless communication. The wireless range is very poor. It does not work for more than 20 meters line of sight with a fractus chip antenna chip antenna. We have tried a whip antenna as well and the range does not seem to increase drastically.
 Following are the actions we have tried to rectify the issue:
 1. We have done the layout in the PCB exactly as in the reference design CC2500 EM and we did boards with both chip as well as for whip antenna 
2. We have worked with fractus to get the chip antenna position and layout cleared by fractus 
3. We are transmitting at maximum allowed power 
4. We are doing frequency offset compensation as per the TI application note
 The problem seems to be one of the below two (we are guessing here)
 1. Either there is too much frequency drift between transmitter and receiver 
2. There is mismatch between the CC2500 and the antenna

We are not able to identify exactly why the range is less.

  • 0
    TI__Mastermind 36395 points

    Chandrashekar, 

    For any of these transceivers there is also a trade off between data rate and range, can you disclose your RF settings, preferably in XML format from SmartRF studio directly.

    Regards,
    /TA

  • 0
    TI__Mastermind 39860 points
    Seems like your debugging is based on a range test. You have developed new HW, new SW and using an antenna with unknown performance. When you set up an RF link and get poor range you have no way of knowing where the problem is. Thus, before setting up an RF link you need to test TX, RX and antenna performance separately to narrow down the problem.

    TX: Use a good known SW (e.g. SmartRF Studio). Disconnect antenna and solder a semi-rigid coax between the LC filter and the antenna feedpoint. Measure output power and frequency error using a spectrum analyzer

    RX: Measure sensitivity. Again, disconnect antenna and solder a semi-rigid coax between the LC filter and the antenna feedpoint. See DN002 Preactical Sensitivity Testing (http://www.ti.com/lit/swra097) for ways to do the testing.

    Antenna: Measure the antenna performance using a network analyzer. Add matching components if needed. See e.g http://www.ti.com/lit/swra161, section 6 of measurements to carry out.

    Test your SW using a good known HW (e.g CC2500EM)

    Once the above is completed and found to be ok you can set up an RF link.