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41641Re: [softrock40] Re: An Idea, tell me what you think:

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  • Loftur Jónasson
    Mar 2, 2010
    • 0 Attachment
      Hi all,

      Just to chime with my two cents :)

      > There is a "black hole" in the ham kit/product market it is the
      VFO.
      > What is needed is a VFO kit (DDS or Si570-based) with an actual
      > "spinner" knob that covers near DC through 120 MHz (for divide by
      four
      > PC-based SDR's) or at least near DC through 75MHz for dual
      conversion
      > superhets with 45MHz first IF and 455kHz second IF. There is
      nothing
      > like this out there. We have ADI9834/5-based knob VFO's that go
      through
      > 34MHz or 21MHz with pretty lousy SFDR, then there are the AD99XX
      DDS's,
      > expensive and I don't know of one with a tuning knob.
      >
      > Yes I know about KB5CQ's Si570 tuner/display, it is not a
      "spinner".
      >

      The firmware developed for the Mobo 4.3 includes a rotary encoder enabled, variable speed VFO.  The firmware, while tailored towards the Softrock 6.3 / Mobo 4.3, can easily be adapted to any other platform, and all source code is free for use and rework, as long as it is not for commercial purposes.  What I'm alluding at, is that if anyone wants to make a standalone VFO project based on the Si570, then you are welcome to use the Mobo 4.3 firmware as a base.  It runs on any Atmel 8bit USB enabled Microcontroller (AT90USBxxx, ATmega32Ux..., virtually unchanged.  Only addition needed is a Si570 and a decent Rotary Encoder and a nice heavy VFO knob.

      http://groups.google.com/group/MOBOKITS (you need to be registered, but anyone is welcome)

      http://sites.google.com/site/lofturj/mobo4_3

      The SDR Widget project which has also been mentioned a few times here on the softrock40 list, will include the full Mobo 4.3 firmware functionality, in addition to being a high quality 192kb/s 24 bit audio card, eliminating the need for anything other than one USB connection between the SDR and the PC.  Who knows, it may also evolve into providing direct DSP audio processing, we'll see :))
      This project, while still in its infancy, already has a working USB composite device consisting of a set of DG8SAQ/Serial/HID/Audio devices (no small feat, singlehandedly by Alex, 9V1AL).  As this is a volunteer group effort by a number of dedicated radioamateurs, we expect to have a working configuration ready in a few months.  Ohh, and yes, it includes a VFO :))

      http:/groups.google.com/group/SDR-WIDGET

      73 de Loftur, ve/tf3lj

      2010/3/2 Lieuwe De Vries <lieuwe.devries@...>
       

      A similar project?


      From: k5nwa <k5nwa@...>
      To: softrock40@yahoogroups.com
      Sent: Mon, March 1, 2010 7:09:04 PM
      Subject: Re: [softrock40] Re: An Idea, tell me what you think:

       

      There is already a kit available that uses a knob to control the Si570 chip;
      < http://www.qsl. net/k5bcq/ Kits/Kits. html >

      It works well and it's configurable.

      At 11:36 AM 3/1/2010, you wrote:

      >N3ZI's new 2010 DDS definitely has a "spinner" control, using a
      >mechanical encoder. There's a youtube video of the tuning action.
      ><http://www.pongranc e.com/super- dds.html>http://www.pongranc e.com/super- dds.html
      >
      >
      >But even if you don't like mechanical encoders it is compatible with
      >Optical encoders, and has several tuning parameters that can be
      >tweaked via the serial port. (And don't flame me about serial ports,
      >you can buy a USB to serial port converter on ebay for $2, shipping
      >included, and yes, it works fine with them)
      >
      >I'm not sure what you mean by "switch band-pass filters/sidebands
      >etc" that's not really part of a DDS. But if you are talking about
      >a function that has outputs to select bands, sidebands, etc., based
      >on the DDS frequency. There's no spare I/O anyway, but you could
      >easily add a PIC attached to the serial port that does that. Other
      >people have done that.
      >
      >It uses a AD9834, slightly overclocked( 80MHz) output up to
      >34MHz. With an IF in the ~10MHz range you can get high side up
      >through 15 meters. If you really want high side on 10Meters then
      >you are out of luck, but if you can design a filter to knock out the
      >8MHz image in this case then you shouldn't be fooling around with
      >this stuff anyway.
      >
      >If you need 4x and sqaure waves you shouldn't be using a Analog DDS
      >anyway, use a Si570, much cheper and wider range.
      >
      >The code is written in "C" and is not released. It would be far
      >easier for a qualified individual to write it from scratch than it
      >would be to figure it out. Writing code that works is one thing,
      >writing code so that someone else can understand it is much more complex.
      >
      >
      >--- In softrock40@yahoogro ups.com, "drmail377" <drmail377@. ..> wrote:
      > >
      > > There is a "black hole" in the ham kit/product market it is the
      > VFO. What is needed is a VFO kit (DDS or Si570-based) with an
      > actual "spinner" knob that covers near DC through 120 MHz (for
      > divide by four PC-based SDR's) or at least near DC through 75MHz
      > for dual conversion! superhe ts with 45MHz first IF and 455kHz
      > second IF. There is nothing like this out there. We have
      > ADI9834/5-based knob VFO's that go through 34MHz or 21MHz with
      > pretty lousy SFDR, then there are the AD99XX DDS's, expensive and I
      > don't know of one with a tuning knob.
      > >
      > > Yes I know about KB5CQ's Si570 tuner/display, it is not a "spinner".
      > >
      > > Plus, every time I run across a DDS knob VFO I can buy (only one
      > comes to mind) there is no open firmware source so I can switch
      > band-pass filters/sidebands etc. Locked-up tight.
      > >
      > > This is the first building block we need.
      > >
      > >
      > > --- In softrock40@yahoogro ups.com, "Peter" pete@ wrote:
      > > >
      > > > Would there be demand for a small line of SDR building-block
      > kits? What I'm thinking of is perhaps a motherboard with RF, IF,
      > and USB connectors as well as a power supply, and headers to accept
      > interchangeable filter boards, interchangeable QSD or I/Q mixer
      > boards, interchangeable LO boards, interchangeable audio, USB
      > isolator, perhaps a digitizer, etc. Probably would use surface
      > mount parts throughout, but would allow staged assembly, and a
      > newbie could buy some blocks assembled and others as kits, and
      > would be able to try out surface mount techniques without risking a
      > large, expensive project. It would also allow for low-cost
      > experimentation with different approches to LO, QSD, interface,
      > etc. Would something like this be worthwhile?
      > > >
      > > > 73,
      > > > Pete, NI9N
      > > > www.garage-shoppe. com
      > > > www.lazydogengineer ing.com

      > > >
      > >
      >
      >
      >

      Cecil
      K5NWA
      www.softrockradio. org www.qrpradio. com

      "Blessed are the cracked, for they shall let in the light."



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