ADALM Pluto Rev D

  • Danke.

    Wie heißt denn der entsprechende Stecker?

    Muss man irgendwie per Software die interne Clock abschalten? Muss das Signal auch 40 MHz haben? Oder würden auch die üblichen 10MHz gehen?



  • Der Stecker heißt u.FL und Analog Devices empfiehlt 40 MHz.

    Es gibt einen OCXO bei eBay und Aliexpress, der auch Vielfache von 10 MHz liefert, nach OCXO 20m suchen.

    Mit 3 dB Dämpfung müsste der Pegel stimmen.

    73 Detlev

  • Hi,

    Danke für den Tipp, ich habe das Ding für 27,03€ bei Aliexpress gefunden. Habe es bestellt, bin mal gespannt, ob es wirklich am versprochenen 11.JUL ankommt. Ist billiger als ein zweiter GPDSO für die 40MHz.


    Georg, DD8ZX

  • Hi Georg,

    bei mir hat die Lieferung 11 Tage gedauert. Ich habe die Frequenz mit einem Frequenzzähler mit GPSDO auf 40 MHz gezogen, sie wird ein paar Minnuten nach dem Einschalten wieder erreicht. Die Spannungsversorgung (8V) muss allerdings stabil sein, 0,5 V mehr oder weniger ergaben 1 dHz Abweichung.

    73 Detlev

  • Hello All,

    my question is about using SDR Console (V3.0.27) and Adalm Pluto (Rev. D) with an external 25MHz reference.

    Pluto configuration for external reference was done according to section “Alternative reference frequencies”.

    The modification went well which was confirmed by software and hardware (Pluto’s buffer of the external reference signal (LTC6957) turned on and internal 40 MHz TCXO turned off; 25 MHz reference signal comes to the XTALN pin of AD9363)

    After Pluto is connected to the computer the device is seen as a memory but when trying to “Start radio” it says that the device was not found.

    It was tested on two computers and with different external reference frequencies - 25 and 40 MHz.

    Maybe something needs to be changed in SDR Console settings with which Pluto worked fine before the modification?

    73 de Karen, ra3apw

  • Hi,

    after destroying my old Pluto I have now Rev. C/D, connected to PC via LAN. Do I need the ground modification as described in this video at 07:35

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    I cannot find D3 and R58 is not assembled.

  • Hallo,

    with the rev C/D Pluto no change in hardware is nessecary. But if one will use an external clock, a modification of the environmetal variable is requested. Use a short coax cable with a plug named "u.FL" to connect the external signal source.
    Login to Pluto with putty or similar tool. The name is "root" and PW "analog". Please Note, the PW is not visible while typing. After some other modifications (see CQ-DL download area) type

    # fw_setenv refclk_source external

    # pluto_reboot reset

    There is a paper in German about the Pluto changings, if interested, send me an email,


  • Hello,

    After connecting an external VCOCXO 40 MHz from Connor-Winfield via u.FL connector, I got a reproducible problem.
    Changing to external reference:

    # fw_setenv refclk_source external

    # pluto_reboot reset

    I see a spurious signal near the CW beacon (WebSDR England):

    I see nothing with the same settings in SDR-Console but internal source in Pluto:

    # fw_setenv refclk_source internal

    # pluto_reboot reset

    Do I miss something or do I have the wrong oscillator ?
    Datasheet of my 40 MHz oscillator:

  • Hi,yes 3V3 is too high. It is noted in the shematic that the max input power is 10dBm (at 50Ohm).
    The LTC6957-3 has a signal input level range from 0.2 ... 2 Vpp. The output is square wave CMOS. After division by 2 the voltage at XTALN of AD936x is abt. 1.6V.

    In a document from AD you can find " The level for the signal should be 1.3V pk-pk maximum(lower swings can be used but will limit performance). This signal can be a clipped sinewave or a CMOS signal. The best performance will be seen with the highest slew rate possible"
    With the onboard 40MHz oscillator I meassured abt 1.3Vpp.