uBITX Transceiver semi-kit build

Discussion in 'Homebrew and Kit Projects' started by KD8UYQ, Aug 14, 2018.

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  1. K9STH

    K9STH Platinum Subscriber Volunteer Moderator Platinum Subscriber QRZ Page

    I have a spectrum analyzer. However, it doesn't really go much below 25 MHz. I can see if I can get a reasonable "view" on 75-meters. But, I am really thinking that there will not be any useful information gained by the experiment.

    Glen, K9STH
  2. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Thank you Glen.

  3. AF7XT

    AF7XT Ham Member QRZ Page

    Bob ,
    I'll be following along with little to add other than a hastily found link and an explanation.
    There is a local here that has been on the uBitx path in fits and starts for the past few months .
    He already had a bandpass board from a previous project and reports favorable results so far.
    I provide the link as an example as I have no idea what he is using other than it is 9 band and QRP.
    He also reports that AGC is nearly a must.
    I'll be watching ...:D
  4. KD8UYQ

    KD8UYQ Ham Member QRZ Page

  5. AF7XT

    AF7XT Ham Member QRZ Page

    ...So do I . I have a few old but useful projects that would with out a doubt benefit from a bit of front end selectivity. From my goofy VNA and FFT/Spectrum analyzer to an eventual uBitx. Although most of the projects I've been involved with are RX only I don't see any reason why "most" of them would not tolerate 10 watts.
    I've had to use not only attenuation but bandpass to go looking for specific signals in a harmonic rich environment more than once.
    I'll tell you about it someday and I promise I won't have to kill you when I'm done. ;)
  6. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Hi Dennis,

    Roger that

  7. N1OOQ

    N1OOQ Ham Member QRZ Page

    Welcome back, Ripley! How's the amp running?
  8. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Hello Tom,

    The amp is doing fine. As part of my radio rotation in the ham shack it is called to service about every 10 days or so. Look for a one year update on that build soon.

  9. KD8UYQ

    KD8UYQ Ham Member QRZ Page

    Well the ophthalmologist scraped a nodule off of my left cornea last Thursday. There is bandage contact (looks like a regular contact lens with no optical correction) on my left eye while it heals so now seeing is like opening your eyes under water. It makes one's day interesting This procedure is in preparation for cataract surgery in both eyes this fall.

    Typing on this laptop is a real challenge and so is working on the uBITX transceiver. However, I did get some stuff done. Kee's AGC board is populated and I mounted the RF gain control (small knob next to the volume control to the left of the display). In addition there is now a DTDP, center off, switch mounted to the right of the display. This will be the AGC switch to select the release time constant and to turn AGC off.

    RF gain and AGC controls.JPG
    The next step is to wire the AGC circuit up and test it.

    Something easier to see and to build was this little wooden box to house the speaker for the prototyping fixture.

    speaker box pic1.JPG

    speaker box pic2.JPG

    Meanwhile I am looking for a cabinet for the second uBITX transceiver that will be used in the ham shack and the field. This is going to be challenging because I decided on a plug-in type chassis design. The mother cabinet will house a 12 volt 20amp power supply, a CCI 100 watt PA board, and LPFs for base station operation. The uBITX radio itself will doc to this but easily disconnect to run on an external 12 volt 5 amp power supply cube or LiPO batteries for mobile use.

    Me thinks I will be doing some machine work in the near future....well when my eyesight gets better anyway :confused:.

    KK4CUL likes this.
  10. K6BSU

    K6BSU Ham Member QRZ Page

    Interesting project. The "software" referenced leaves me cold. Do I need to do programming in order to make it work?
    KK5R likes this.

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