QRP Labs VFO Kit

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  • Опубліковано 27 лис 2024

КОМЕНТАРІ • 9

  • @klejzbigniew
    @klejzbigniew Місяць тому

    You sure saved the projects

    • @TheArtofEngineering
      @TheArtofEngineering  Місяць тому +1

      So many projects so little, time, patience, skill etc!!! 🤣🤣

  • @F_Tim1961
    @F_Tim1961 9 днів тому

    According to the Hans S verbiage there is no RIT for CW use at present. I don't know what IO pins are still available if any - it takes around 7 pints to drive and LCD display for example.
    This is what he says it has
    Rotary-encoder tuned output covering full Si5351A frequency range 3.5kHz to 200MHz
    Fixed (configurable) independent output, also in the range 3.5kHz to 200MHz
    Extended range up to 292MHz has been experimentally measured (in breach of the datasheet, of course)
    IF Offset (positive or negative) to support superhet radios
    Multiplier to support radios using Quadrature Sampling Detector type mixers (e.g. as in most SDRs)
    Quadrature output mode (Clk0, Clk1) for driving Quadrature Sampling Detectors directly - 3.2MHz and above
    3.3V p-p squarewave output
    GPS can optionally be connected to maintain precise frequency
    16 configurable frequency presets
    Control of 6 relays using the relay-switched LPF kit
    4 auxiliary outputs for controlling other things (similar to Aux on the Ultimate3S kit)
    Selectable tuning rate 1Hz to 10MHz

  • @technishn
    @technishn Місяць тому

    The Output from the Si5351 pcb is DC coupled so a DC blocking capacitor is needed. Additionally the Si5351 prefers light loading otherwise harmonics and phase noise are degraded

    • @TheArtofEngineering
      @TheArtofEngineering  Місяць тому

      Thanks yes. The receiver module has a 100nF cap on its header. 73 de VK2AOE

    • @F_Tim1961
      @F_Tim1961 9 днів тому

      INdeed, various have tried to put in an impedance conversion RF transformer immed after the Si5351 and killed it instantly. The 100nF capacitor that is required saves all- and in fact can provide blocking the transformer if people want to put that in.

  • @F_Tim1961
    @F_Tim1961 9 днів тому

    I have a hardware fix for solving the lack of RIT issue as long as you are using a crystal controlled analogue Osc as your Tx oscillator into a standard SSB IF strip, with a capacity to unbalance the modulator to produce CW directly . AS it stands the VFO Gen from Hans unit is not set up to support direct on Freq RF gen, CW tx, with IF offset with Rx. It's set up for IF offset on Tx and Rx as per a normal SSB Tx if you use IF offset at all.
    TEF

    • @TheArtofEngineering
      @TheArtofEngineering  8 днів тому

      What I thought I might do, is set one clock to double the required freq with an offset of double the CW offset (say 1200Hz). Then I would feed it through a divide by 2 and into the receiver?

    • @F_Tim1961
      @F_Tim1961 8 днів тому

      @@TheArtofEngineering My thoughts a re to have an Osc which is completely idep of the Carrier inject osc which is used to recover SSB voice and CW (via an offset beat) . That gets injected on TX only just downstream from the mixer. (the Mixer osc being disabled by a Mos switch at this time_. When On Rx the other side is sending CW to match The Tx frequency he perceives but this is offset from the IF freq and carrier Inject osc by whatever pull you put on the CW only osc. That will therefore form tone when decoded. I can mark up a bit-x type design with the suggested change d but the injection can be as simple as a 100nF capacitor as long as when the CW carrier Osc is not running it presents a high impedance in terms of what the existing mixer might see. Ie you don't want to bleed down the incoming RF from the IF to nothing by some ham handed addition.
      It also means par consequence, that the Tx Frequency will be 600 Khz offset from what your display might show(unless the VFO firwware is bodgied by the designer and a DI input tells it "I am in transmit mode now ") but worse things have happened(in terms of offset displays etc ) .
      Should make sense
      TEF