EU1KY Antenna analyzer with STM32F7Disco (DH1AKF mods)

Discussion in 'Homebrew and Kit Projects' started by DH1AKF, Jan 10, 2018.

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  1. DL9DAX

    DL9DAX Ham Member

    Hello Wolfgang,
    when you look at the power management board, you see there a voltage divider R3/R4 attached to the battery. I connected JP5 (labelled :To ADC) to the ADC and it displays some voltage. I think, making the divider not 1:1 but as 12K/43k gives a better resolution of the battery voltage. So right now it works, but the scaling factor is wrong because of the different divider. Can you add a calibration option to the software, so that I can adjust the voltage reading to the actual used divider ratio ?
    Actually, I also recommend to but this additional wire needed on a better visible point of your homepage, because I first assembled everything according to the instructions and then I tried to trace down the problem with low voltage reading. So I had to open the case again to fix it....

    73, Uwe
  2. DH1AKF

    DH1AKF Ham Member QRZ Page

  3. DL9DAX

    DL9DAX Ham Member

    Hello Wolfgang,
    thanks for the fast answer. The cell I have goes to 4.2 V. According to STM schematics the ADC is supplied by 3V3. According to the lithium battery is full with 4.2 V. With the 12k/43k divider on the power board you just get 3.28V, so it is on the safe side. It looks, like the display is working properly, I see a voltage of 6.84V for a nearly full charged cell. It is just, that the scaling factor based on 10k/10k for the voltage reading is not okay. Because it is more easy to solder just a single wire than to look for two resistors, this method is preferable. It also gives the better voltage resolution and should therefore give a more precise gauge value.
    I am still curious and maybe take a look in the source code and fix it on my own. But because the voltage divider is already on the PM v1.1 board I think it is a good option for all.
    73, Uwe
  4. N5KZW

    N5KZW Ham Member QRZ Page

    I am having a problem with the OSL calibration function. When I select OSL calibration, the menu button blinks once, but otherwise does nothing. This problem occurs on every S/W version I have tried. Can you offer any suggestions?
    TNX, Ed
  5. DH1AKF

    DH1AKF Ham Member QRZ Page

    Hi Ed,
    is there a signal in "generator mode" ?
    Another suggestion: try again with a blank SD- card, (maybe it has an old incompatible file structure...)
  6. OK5KWT

    OK5KWT Ham Member QRZ Page

    I would like to opt in where I could find an item in your firmware

    Configuration" window. Select configuration parameter SI5351_CORR and set the measured frequency difference

    for frequency calibration. Thanks for the info
  7. OK5KWT

    OK5KWT Ham Member QRZ Page

    I already found it .. I forgot the hidden items
  8. KM6ORN

    KM6ORN Ham Member QRZ Page

    I just got a new eu1ky kit from elekitsorparts and got it running with the stock firmware. I checked it on both a dummy load and my 20m dipole and everything was dandy. Great, right?

    After that I installed the improved firmware, following the directions in the version 1.4 pdf. Now, whenever I scan any antenna at any frequency it gives me an swr of 1.0, and in the single frequency measurement mode it says "Ls out of range" instead of giving me the impedance. I've gone through the hardware and OSL calibration three times and tried it on four different antennas with the same results.

    Anyone have any thoughts on how to address this? Is there a better place than this for me to ask? Thanks for any help!
  9. DH1AKF

    DH1AKF Ham Member QRZ Page

    Hi Aaron,
    here my thoughts and hints:
    - Did you forget to replace the jumper "HWCAL /WORK" into the right position ("Work") after HW- Calibration??
    - What does the Generator menu say?
    Hope this helps.
    73, Wolfgang
  10. EI8DRB

    EI8DRB Ham Member QRZ Page

    Hi Aaron...
    I have had issues with v. low levels since upgrading to the DH1AKF formware. Basically if I look at DSP there are no peaks. I have 2 different boards that behave the same. I also re-did my audion connections on the Disco board to be sure, but no difference. When I get a chance I will try reverting to the original f/w to see if this helps.
    / Gerry

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