Help needed with forty 9er dds vfo conversion

Discussion in 'Homebrew and Kit Projects' started by KD9GGZ, Sep 6, 2021.

ad: L-HROutlet
ad: l-rl
ad: HRDLLC-2
ad: Left-2
ad: abrind-2
ad: L-MFJ
ad: Left-3
ad: MessiPaoloni-1
ad: L-Geochron
  1. KD9GGZ

    KD9GGZ Ham Member QRZ Page

    Problem with the audio and recieve after converting a forty9er to a dds vfo. Audio is extremely quiet and the recieve randomly has major noise spikes from what seems like nowhere. Any help will be appreciated.
     
  2. KB1CKT

    KB1CKT Ham Member QRZ Page

    How did you connect the DDS? IIRC the NE602 needs a low level of like 200mVpp, but it's been years since I read about it. Can you give a schematic of how you connected the DDS, and voltage levels (peak to peak)?
     
  3. KD9GGZ

    KD9GGZ Ham Member QRZ Page

    Yes I will have to get the prints. I built it with the plans from one of the arrl books for arduino but I believe the dds is direct connected to the main crystal point on the board. Do not know the voltages but can check next week as I will be home and able to check
     
  4. K1LKP

    K1LKP Platinum Subscriber Platinum Subscriber QRZ Page

    https://kk9jef.wordpress.com/2016/08/10/qst-forty-9er-with-dds-vfo/

    https://manualzz.com/doc/42613183/a-modular-40-meter-cw-transceiver-with-vfo

    https://qsl.net/oe7mbt/fotrty9er_dds.html

    YOU MIGHT HAVE TO BACKOUT OF THE CONVERSION TO FIND OUT WHERE
    THE PROBLEM IS.

    THERE IS ALWAYS A RISK FACTOR WHEN DOING A CONVERSION.

    CAN YOU POST ANY DETAILS ON WHAT THIS CONVERSION ACTUALLY IS.

    73 - K1LKP
     
  5. KD9GGZ

    KD9GGZ Ham Member QRZ Page

    The conversion is the same as the WordPress site you mentioned but I built my own breadboard, as it was for a 4h project, also as far as we can tell transmit is great it's just recieve.
     
  6. K1LKP

    K1LKP Platinum Subscriber Platinum Subscriber QRZ Page

    OK.....

    THANK YOU FOR YOUR FEEDBACK.

    transmit is great it's just rx.

    IT'S TIME TO TAKE THE PLUNGE.........

    YOU HAVE TO BACK OUT OF THE CONVERSION
    TO MAKE SURE THAT THE DEVICE IS WORKING
    OK.

    THIS IS THE FIRST STEP IN WHAT IS KNOWN AS

    THE "SANITY CHECK" IN THE TROUBLESHOOTING
    WORLD.

    REMEMBER.... MURPHY'S LAW.........

    AND

    POOP HAPPENS

    73 - K1LKP

     
  7. KL7AJ

    KL7AJ Ham Member QRZ Page

    sounds like insufficient drive from the DDS
     
  8. KD9GGZ

    KD9GGZ Ham Member QRZ Page

    That's kinda what I was thinking
     
  9. W1VT

    W1VT Ham Member QRZ Page

    A DDS isn't as clean as a simple VFO. Spurs may be an issue.
     
    N2EY likes this.
  10. VE2GCE

    VE2GCE Ham Member QRZ Page

Share This Page