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Does Ham Radio need a $15 two-band SDR receiver kit?

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  • kb9yig
    Does Ham Radio need a $15 two-band SDR receiver kit? I have a new single-board SoftRock design that provides two band coverage in a $15 kit. The kit will
    Message 1 of 37 , Feb 27, 2006
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      Does Ham Radio need a $15 two-band SDR receiver kit?

      I have a new single-board SoftRock design that provides two band
      coverage in a $15 kit. The kit will include the PCB and all
      components to provide coverage of a portion of the 80m (3.5 - 3.55
      MHz with 96kHz sampling) and 40m (7.0 - 7.062 MHz with 96 kHz
      sampling) bands. (With 48kHz sampling the band coverage will only be
      7.0 - 7.038 MHz and 3.5 - 3.531 MHz. Some coverage below the two
      bands also is part of the tuning range with each of the sampling
      rates. With the right 4x-8x crystal frequency the band coverage
      could be better placed.)

      Band switching will require moving a jumper plug between two pins
      out of a three pin header group or connecting a SPDT switch to the
      three pins. The BPF will be made broad enough to cover the two
      bands without excessive compromise.

      The new design provides a balanced QSD circuit and is best suited
      for low band operation since it uses a crystal at 4x and/or 8x
      frequency. However, the design will lend itself well to single band
      coverage for 160m operation or even AM broadcast or other low
      frequency ranges.

      The PCB for the new design is 1.5 x 1.9 inches and all circuits,
      oscillator, BPF, QSD clocking circuits, QSD and audio amps are on
      the one board. A build board will have a height of just under 5/8
      inches.

      I will be ordering prototype boards later today and will have eight
      extra kits if anyone would like to play with the new design.
      Prototype kits will be at the production kit price of $15 and be
      shipped the second week of March.

      Another feature of the design is to provide a mute input line on the
      QSD circuit.

      That brings us back to the original question - does Ham Radio need a
      $15 SDR receiver kit?

      Comments would be appreciated.

      73,
      Tony KB9YIG
    • KY1K
      Hi Tony, I m late to respond, but I did read all the other responses before sending this. Regarding the 2 band softrock-yes, of course we would like it.
      Message 37 of 37 , Mar 1, 2006
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        Hi Tony,

        I'm late to respond, but I did read all the other responses before
        sending this.

        Regarding the 2 band softrock-yes, of course we would like it.

        However, I have grave concerns regarding the wideband front end,
        especially since the 2 bands chosen are harmonically related. No one
        else has expressed concern over this, and I'm NOT quite sure why::>

        With a wideband front end, the softrock will hear 80 meters and 40
        meters at the same time. Note that there is some attenuation if a
        single band antenna is used, but that any 40 meter signal that makes
        it to the antenna input will be heard with very little attenuation
        due to the nature of the beast...WE AREN'T USING A SUPERHET TO LIMIT
        THE RESPONSE TO UNDESIRED BANDS!

        I think that even relatively weak signals on 80 meters will be heard
        on 40 meters.

        I know it's a low cost demonstration platform, but few users would
        find it acceptable to wonder whether the signal they're listening to
        is on 40 or 80 meters!!

        I'd use the narrowest filter I could and have 2 filters, one for each band.

        I hope the beta testers evaluate this aspect of the new dual band softrock.

        Art



        >I have a new single-board SoftRock design that provides two band
        >coverage in a $15 kit. The kit will include the PCB and all
        >components to provide coverage of a portion of the 80m (3.5 - 3.55
        >MHz with 96kHz sampling) and 40m (7.0 - 7.062 MHz with 96 kHz
        >sampling) bands. (With 48kHz sampling the band coverage will only be
        >7.0 - 7.038 MHz and 3.5 - 3.531 MHz. Some coverage below the two
        >bands also is part of the tuning range with each of the sampling
        >rates. With the right 4x-8x crystal frequency the band coverage
        >could be better placed.)
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