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Re: RXTX modifications

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  • Taka Sugi
    Hello Sandro I think modification for 20/17/15m is not so difficult. Local oscillator Si-570 will cover all bands of HF. Frequency is set by the software such
    Message 1 of 5 , Aug 30 12:54 AM
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      Hello Sandro

      I think modification for 20/17/15m is not so difficult.

      Local oscillator Si-570 will cover all bands of HF.
      Frequency is set by the software such as PowerSDR V.19.3.15(*),
      other SDR software and you are able to set any band,frequency.
      (*)http://code.google.com/p/powersdr-iq/downloads/list
      I have been using this PowerSDR software.
      The band:160/80/60/40/30/20/17/15/12/10/6 m will be set by
      this software.
      Even if you modify to 20/17/15m bands, you can receive other
      bands,but the sensitivity goes down for other bands.
      Transmitting for other bands is another story.TX output LPF
      (Fc=24MHz) limits maximum frequency.
      Please note that tune circuits are designed forgcenter band",
      20/17/15m (for your modification) : 17m
      and as the result, a peak sensitivity will be set atgcenter bandh.

      73 JA1TLH/Taka


      > Hi Taka,
      >
      > The modification of the LPF appears to be well-suited for new bands. Thank you for facilitating the calculations.
      > I do not know how the fimware for the selection of frequencies. 10m to 160m operating range, limited only by the LPF?
      > Just follow your suggestion and is ready to change, right?
      >
      > PY1PE Sandro
      > ps: Sorry English, but is the translation of google.
      >
      >
      > --- In softrock40@yahoogroups.com, "taka_sugi1206" <taka_sugi1206@> wrote:
      > >
      > >
      > >
      > >
      > >
      > >
      > > Hi, Sandro
      > >
      > > I didn't understand the word "motagem", Portuguese?
      > > but I guess this means "ensemble".
      > > Anyway,I simply calculated each parameters for 20/17/15m set.
      > > Basic idea@: center frequency of the set=18MHz(17m)
      > > 1. Tune circuit : f=1/2ƒÎã(LC) at 18MHz
      > > 2. TX Output LPF: cut off frequency fc=24(MHz)
      > > fc=21MHz x 1.2
      > > This is defined by max. frequency of the set:15m(21MHz)
      > >
      > > Estimated parameters@for 20/17/15m set modification.
      > > T2: T30-6@Primary: 10t/Bifilar 0.36uH
      > > Secondary: 20t/1.44uH
      > > C20: 56pF
      > > T3: same as 30/20/17m
      > > T4: same as 30/20/17m
      > > L1: T30-6/18t 1.17uH , C21: 68pF
      > > L2,L3 : T37-6 12t/ 0.43uH , C24,C26: 100pF , C25:220pF
      > >
      > > C27: 100pF , L4: same as 30/20/17m@
      > > C39: 120 or 150pF , T5: same as 30/20/17m
      > > T6, R55/R58 : same as 30/20/17m
      > >
      > > Please comment on this idea.
      > >
      > > 73 DE JA1TLH/Taka
      > >
      >
    • oz2da
      Thank you for the information. OZ2DA Dennis Andersen
      Message 2 of 5 , Apr 29
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        Thank you for the information.


        OZ2DA

        Dennis Andersen

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