LimeSDR Mini

    Hi Claudio,


    I use a LimeSDR mini for both RX & TX with SDR Console software, using however windows 10 it works fine. I would try to see if the Limesuite software loads under Win 7 as that updates the LimeSDR mini's firmware. The driver and software installation is though detailed here https://wiki.myriadrf.org/LimeSDR-Mini_driver_installation https://wiki.myriadrf.org/Lime_Suite


    Whilst I can't comment much on Win 7 I can add some comments on the LimeSDR mini and an external clock.


    The external clock in the mini is actually applied by physically switching R59/62 i.e. a hardware modification has to be applied and the switch from internal clock to external cannot be made by software alone. A connection has to be made to a U.FL on-board connector. So it's not very straightforward and needs some fine SMD work.

    Doing some tests with Lime Suite the mini seems a bit 'picky' regarding the external clock values it runs with and I ended up using 40MHZ which is the same as the internal VCTCXO, having done that another problem manifest itself as the mini then fails the stock quick tests and calibrations (I noticed also that the SDR console log threw errors as well). The errors relate to the fact that the mini's VCTCXO is, it would seem, 'exercised' by the DAC providing it's control voltage and expects to see a corresponding change in the VCTCXO's output frequency, a reasonable test to be applied to ensure overall functionality but clearly with the internal oscillator disconnected cannot take place.

    I ended up restoring the original hardware link to the internal VCTCXO and trimmed its 40MHZ output by means of a loosely coupled and GPS locked service monitor whilst adjusting the DAC via Lime Suite. The final value is then written to the mini and persists. I would though say that a degree of luck is needed to hit the right frequency as the DAC resolution is quite coarse. This I see is already documented in the Myriad Discourse forum where a possible substitution of the DAC is suggested it would though require also that the software is rehashed accordingly.


    The LimeSDR mini mini works great for me with no problems at all and the internal VCXTO is proving quite stable once trimmed it is though a quite coarse adjustment as has been commented on in the Myriad Discourse. Some have replaced the DAC with a higher resolution device but that means a rehash of the firmware as well. If i experience any drift or need ultimate precision I will swap the resistor again but for now it is fine and SDR console with the new beacon lock trims out any discrepancy.


    Hope this helps and I hope someone can comment regarding Windows 7 and limesuite.


    Best 73


    Clive, G4KCM