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About CC430f6147 Antenna design

Dear all : 

    i have a big problem about antenna design

i follow this document circuit to design my schematic : MSP430 Hardware Tools User's Guide (SLAU278P) page133  

but i don't know what problem about my design

the antenna can't not work 

i had check my circuit, the schematic is same as  the document describe 

the mcu function is ok, program is current ,too

only antenna can not receive any message packet

can anyone help me? that is very important for me

  • - Are you able to receive or send something conducted. Start by using a CW and see if you get energy on the air or if the RSSI increases (Tx/ Rx)
    - It looks like you have populated both R1 and R2.
    - Why do you have two parallel paths? Using a CC430 the top path is the recommended one, you could have added a helix in this part and used a passive component as switch.
  • Hello

    Thank you very much for your reply~!!! >""<

    I tset one EM430F6147RF900 board to send a packet to another EM430F6147RF900 board

    my program can work in this case

    but when i use one EM430F6147RF900 board to send a packet to the circuit (design myself)

    the circuit can not get any packet

    (The test method is set a break point in mine receive interrupt program)

    When use the EM430F6147RF900, i can see the program stop at the break point

    but when use mine design board, it can not get anything, the MCU just wait for the receive trigger
    -----------------------------------------------------------------------------------------------------
    - Are you able to receive or send something conducted. Start by using a CW and see if you get energy on the air or if the RSSI increases (Tx/ Rx)

    I only test receive function, it can not get anythis now~!

    "Start by using a CW and see if you get energy on the air or if the RSSI increases (Tx/ Rx)"

    What is the CW @_@??

    if can not receive packet, is the RSSI still varies?

    -----------------------------------------------------------------------------------------------------
    - It looks like you have populated both R1 and R2.

    The R1 and R2 are design as a switch, not parallel work~!

    -----------------------------------------------------------------------------------------------------

  • The first figure is the slave board
    The lower figure is the Master board

    Slave board only wait the packet to trigger the interrupt, and request the message

    i only test the slave board now~

    and use the EM430F6147RF900 to be the Master node
  • CW- Carrier wave or tone.

    RSSI is the energy in the channel. Use cont Rx and read out the RSSI to debug if you receive anything. For Tx debug use a known good board to measure RSSI in case you don't have spectrum. Note that CC430 saturate if the signal in is too strong.

    The picture shows both R1 and R2 mounted, I don't see that they are designed as a switch. I don't understand the two parallel paths, if you want to select between a PCB antenna and a SMA a switch between the antenna and the SMA should have been added after the filtering.

    The board does not follow the reference design as far as I can see from the picture.
  • Hi~ Thanks for your reply again~!!

      (Master node)

    In this picture, you can see both  R1 and R2 are mounted on the PCB board

    That is due to i am not good at mount component , so my friend help me to mount all component 

    so when i ready to test this board, i need to dismount R1 or R2 at the first time

    however, that only ONE  antenna work at the same time

     (slave node)

    Now, i only had tested the slave board, so you can the R2 was removed

    you told me that mine board does not follow  the reference design

    can you show me what's problem about mine design? 

    I really not understand what's wrong about mine circuit

    All component values are same as the reference design guide

    only different is the reference design guide use the 0402 type

    and i use the 0603 type to design my circuit

    Is this situation maybe cause my antenna error?

    Thanks

    Best regard  

    Raier 

  • Hello,


    It was suggested that you try a conducted test.  Have you tried that?  "Conducted" means to use a 50 ohm coax cable instead of antenna's between the two units.  You may need to use attenuators as well so the transmitter does not overload the receiver.  You can purchase 50 ohm, SMA attenuators from Mini Circuits here in the US.  Once you get the conducted test to work, then go back to the antenna test. 


    You may also need RF test equipment (network analyzer) to optimize your matching network if you are not using the TI reference design.  At these frequencies, component parasitics are important.  Changing from 0402 to 0603 size may be part of your problem.  Also, did you follow TI's PCB layout guidelines?


    Regards,

    Eric Hooker

    RF Consultant