Turning FT-991A into a real SDR.

Discussion in 'Homebrew and Kit Projects' started by PY2RAF, Aug 26, 2019.

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  1. PY2RAF

    PY2RAF XML Subscriber QRZ Page

    Hi Everyone!

    A few of you might have followed my 5-month odyssey on embedding a SDR in a FT-991A, without any extra wiring, drops, ports, drills, etc.

    Well, it is a great pleasure to inform that it was actually successful!

    Not for the faint of heart; requires a bit of Main Unit fiddling, replacing the radio's USB hub chip but nonetheless... Doable!

    When I saw the radio's schematics, I saw a USB hub and I started thinking: What would be great to have inside the radio and get downstream to the computer using this port? A SDR OF COURSE!

    The whole thing can be witnessed working in this video.

    Plenty of pictures, schematics, charts and a step-by-step guide in the Project's Wiki.

    73! \o
  2. PY2RAF

    PY2RAF XML Subscriber QRZ Page

    P.s.: It also works with then non-A version.
  3. KK4NSF

    KK4NSF Ham Member QRZ Page

    that is impressive! I must agree that such a job would not be for the faint of heart... but looking at the finished product, it was worth the effort!

    The only question I have is does it handle all of the radios functions, including things like bandwidth filters and so forth?

    Great Job!

    PY2RAF likes this.
  4. PY2RAF

    PY2RAF XML Subscriber QRZ Page

    Hey Dave!!

    Thanks for the kind words.

    So no, these functions are not done using the CAT interface - The notch functions that you saw over there are VoiceMeeter filter functions, mostly to get rid of repeater passing subtone and humming power supplies. It would be doable, though.
    HDSDR has no provisions for it. But I think that SDR# or others might be able to interact with the radio filters using CAT command set.

    This will probably be going my next enterprise. Amazes me the amount of comments of people that buys a 991A and returns it because the menu system, the small footprint, etc and not because the radio: It's all about useability. Man, this is a powerful radio.
    And of course, the obligatory tale, a friend of mine (callsign will be omitted for keeping the friendship reason) bought the 991A and asked me for help because he was not understanding the radio.

    I paid him a visit, made a DSP, notch, contour, RF gain, bandwidth, blah blah blah crash course and then there was something that I didn't remember and I requested for his manual.

    To my shock, his manual was wrapped, untouched, sealed in the factory bag along the map, warranty card and world map ¬¬

    It is what it is - This is a great radio, but surely has its challenge to fully wrangle/master it.

    SO I was thinking... What about a remote front-end mimicking some expensive, spaceful radio full of buttons, pots and a few OLEDs displays?

    I think every radio functionality is exposed through the CAT interface - This remote head could be powered by a Arduino for example and not cost a limb. What to do? Just put it on the radio's USB port and that's it.

    Already ordered a few OLED displays and will PoC it by the end of year.

    73 \o
    AD0AC likes this.
  5. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    WOW! You are an amazing engineer - talk about the true spirit of amateur radio! That's an amazing accomplishment.


    PY2RAF likes this.
  6. PY2RAF

    PY2RAF XML Subscriber QRZ Page

    Hey Dave! o/

    Oh wow man, thank you very much for your kind words! I'm just a overly curious ham radio operator, with good friends and way too much time in hands! ;-)

    If I was able to accomplish that it is because other people were generous enough to share their knowledge, projects, insights, source code, implementations, etc.

    And I feel very very happy to share entirely what I have built with the community, hoping someone can push it even further.

    Thanks again, Dave!! 73!! \o

    - Rodrigo.
    W7UUU likes this.
  7. AD0AC

    AD0AC Ham Member QRZ Page

    That's awesome! I have an original 991 and it has been a great radio for me. I think some of the early teething issues with the finals bias turned a lot of people off the rig, but it is a really nice radio.
  8. 2E0FVG

    2E0FVG XML Subscriber QRZ Page

    Hi Great work , but is it possible to just add a rx out as I have a sdrplay for hf vhf and uhf?
  9. PY2RAF

    PY2RAF XML Subscriber QRZ Page

    Hello, Martin - Sure you can.

    Do the Panadapter Light Edition - link: https://github.com/rfrht/FT991A-PAT/tree/PAT-Light
    $15 in parts, $2 in PCB, Around $10 in Amazon USB Solder iron with thin tip - you got everything you need to do it.

    Take the "SDR Out" coax to your SDRPlay - and you got it. No need to do the entire enterprise.

    Read the fancy manual:

    Good luck and let us know the outcome!!

    73 de PY2RAF.
  10. 2E0FVG

    2E0FVG XML Subscriber QRZ Page

    Wow great but is this something you sell ?

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