Posts by DL5LF

    You may not replace the TCXO because it is not easy to remove it without damaging the PCB. Place the new one on a separate (temperature isolated) small piece of PCB near by and disable original TCXO by EN pin (check schematic).

    Good luck...

    Mit dem PoE Adapter hat man generell die Möglichkeit zwei Signale (DC gekoppelt) über die Netzwerk-Verbindung (LAN) zu übertragen.

    Ob das plus/minus (Stromversorgung) ist oder was anderes ist egal.

    Du kannst ein USB-Relais verwenden, das wird von der SW unterstützt. Dann braucht man nicht in dem Pluto löten.

    Ich meine die PTT über die GPIOs geht nur mit alternativen FW.

    Even a TCXO is not stable within the LNB!

    And there is a lack of space in the LNB, it needs a lot of soldering skills to get this done.

    Preferred solution is to feed the 25MHz via cable, preferred LNB has min. two outputs, use one of these to feed the 25MHz. I use a ferrite bead as a transformer as suggested somewhere in this forum.

    TCXO or later GPSDO can be placed in temperated shack 8)


    I simply use a AS169-73 (RF switch). Inputs connected to internal TCXO and a added SMA connector, output connected via 47pF to AD9363ABCZ xtalin input. Appropriate control signals generated from PS_GPIO6 for the AS169 and the TCXO enable (off while external).

    Important to add 20k in parallel to R91!!! This lets the (original) FW think it is a rev. D HW and the ext clock commands will work:


    I equipped my rev.C. pluto with a similar, more simple circuit.

    OS commands for switching between external and internal clock work only if the rev. resistor is modified accordingly. 8)


    You are right.

    I remembered some of the numerous discussions about this topic in this forum, e.g. here


    It shall be square wave within the specified limits: 1.3Vpp. There are also various discussions and measurement results in this forum.


    from 10MHz OCXO (squarewave) you can extract 50MHZ harmonic with crystal and buffer this with inverters and feed into pluto.

    Divided by 2 can be used for LNB! 8)

    Found this somewhere, do not remember where.

    25MHz for the pluto is out of spec as far as I remember , might work or not.

    In a second step you may sync the OCXO to GPS ... 8) ... always good to have enough ham projects

    I do not recommend to remove original TCXO because you have to apply a lot of heat. Disable it by EN input and place the new TCXXO elsewhere on a small PCB.


    Sendest du mit dem GPS gelockten Pluto direkt auf 2.4GHz?

    Dann kann das mit der Ablage eigentlich nicht sein.

    Die Linux Tanssceiver SW hat in der GUI links ein Button, damit sendest du einen (leisen) Ton.

    Hast du im Setup alle Frequenzen richtig eingestellt?

    As far as I remember the SW recognises the HW revision and rev D commands shall not work on rev C HW.

    Basically the command switches a GPIO which controlls the switchi g HW. I modified my Pluto and had to add a parallel resistor to the rev resistor. The same generates an analogue value which is evaluated at startup. Check the associated schematics.

    Someone using a CDCE913?

    It is claiming low jitter, but no data with repsect to phase noise.

    Whats about generating 100MHz with a ADF4351, which is claiming low phase noise VCO?

    Divide this by 2 (50MHz) and 4 (25MHz) for Pluto and LNB. ADF4351 can be refrenced by 10MHz OCXO or GPSDO.