Stabilised universal references for precision radio work

I developed a GPS stabilised frequency reference that goes about disclipining an oscillator in a different way than most.  It can also function as a stand alone WSPR beacon.
The power point file is available on this site named ddsref.ppt  (link below)


We will get a bunch of boards loaded for sale in the next few months. I have a handful of V1.0 blank PCBs (double sided, silkscreened , masked) if anyone wants them.

Additionally, Inspired by other’s work, (VK3WRE/VK3ZYC), I will develop a very small and thin low noise DDS clock generator that uses a 10 MHz input and provides auto switchover to internal. It can generate ANY frequency for any radio.  This can work in conjunction with any external timebase, 10 MHz being a standard. It will also fit in an FT817 without removing other plug in boards.

demo setup for universal frequency reference – $4 oscillator is on the lower LHS.


About glenenglish

electronics, bikes, mountains, propagation, RF systems, modems,
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11 Responses to Stabilised universal references for precision radio work

  1. Steve says:

    a little add-on SNTP or NTP server would make it even more awesome Glenn.
    73 Steve G3XKR / A45WT

  2. Gary Beech says:

    Hi Glen, I am interested in the thin low noise clock generator to used in a LO. I wonder has there been any progress.
    Thank you Gary VK2KYP

  3. Tim says:

    G’Day Glen,
    Just wondering how things are going with this project, I’m keen to lock my 817 :)
    de VK2XTT

    • glenenglish says:

      Hi Tim
      I have been busy with a new born baby and sick mother, but I will be getting the next rev built by December.
      PROMISE !
      Hey I need a few people , so I get a good number, the measure the distance on their 817 between the back of the speaker and the PCB, I want to make sure I dont run out of room and there are no variations out there- as the space is VERY tight and I am using thin PCB to get the room


      • Jim says:

        You seem to pose a question to Tim about ‘board size’, is this meant to fit within a radio? There is some spare room inside an Icom IC-910H radio to one side of the 1296 module and above the synthesizer area.

        I’ve got some technical ability plus oodles of lab equipment (including an HP 8901A Modulation Analyzer good from 150 kHz to 1300 MHz ‘hum and noise’ type measurements and a legacy HP 8591E spec an with the narrow filter BW option as well as several sig gens including the venerable, and spectrally clean, 8640B.)

        73, Jim WB5WPA

        PS. I can also ‘write code’ (as well as debug it) incl assembly.

        • glenenglish says:

          Hi Jim
          Thanks for your email. I am now almost on top of the newborn baby and I have a LITTLE more time. Could you provide details of the room available in the IC910 ? I will endeavour some compatability- though principally V1 will be an FT817 device.

  4. Jim says:

    Hi Glenn.

    I have seen previously a given board size (an early estimate?) of:

    . . . 60mm x 80mm

    which translates to:

    . . . 2.36″ x 3.15″

    And looking at the space in the IC-910H radio with a ruler I can accommodate:

    . . . 3″ x 4″ easily (actually, could go up to 3″ x 6″ with a small cable from the UX-910 module running under the board to a connector it connects to on the PLL board.)

    which translates to:

    . . . 76mm x 100mm (or 76mm x 152mm for the 3″ x 6″ size)

    So, it looks like the 60mm x 80mm form factor board would work inside the IC-910H.

    On height, I have:

    . . . .0.7″ or 17.8mm or by removing two unused brackets (opt. DSP units) one can get:

    . . . .1.2″ or 30mm

    The DSP units are optional in the IC-910H radios (they only operate on already-demodulated voice or audio signals).

    The sizes/area above were ‘sized’ with the optional 1296 module in place in the IC-910H, so there is plenty of room for an additional small board. There is even room on the rear panel for an SMA bulkhead connector to pass in 1 PPS or 10 MHz.

    73, Jim WB5WPA

  5. Gary says:

    Hi Glenn I wonder how this project is progressing.
    73 Gary vk2kyp

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