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612RE: [DVRPTR_V1] RE: RX Window For Commerical Radio Inerface

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  • Ron Wright
    Oct 20, 2013
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      Tony,

      Maybe we got terminology difference.  When one says window it can mean many things, freq bandwidth, voltage levels, etc.  If one want specific info one must state what one is talking about; window for what.

      A window of operation can mean many things and yes disc output of rcvr has many including level and bandwidth.

      if one is to work on this stuff then one needs to have correct terminology to allow one to communicate.  Just stateing a window does not cut it.

      I've built many repeaters and other radio gear and we get all kinds of differences.  Knowing what is needed is often first step in any interface.

      73, ron, n9ee/r

      Ron Wright, N9EE/R
      BSEE
      Micro Computer Concepts
      352-683-4476
      mccrpt@...



      To: DVRPTR_V1@yahoogroups.com
      From: nn1d@...
      Date: Sun, 20 Oct 2013 16:16:59 -0700
      Subject: [DVRPTR_V1] RE: RX Window For Commerical Radio Inerface

       



      No matter what the radio IF is you still need a max and min voltage window injected into the DVRPTR board,

      I'm guess here you never owned a satoshi or moen board,


      So it still don't answer the question.


      All the GMSK boards have both a RX window adjustment and a TX audio adjustment

      not having a RX adjustment is as bad as not having a TX audio adjustment,

      it is possible to over drive the DVR board with too much Disc voltage or under drive the board, unless the DVR board has some sort of AGC in the RX audio circuit to compensate.


      now do you see?  these boards are interfaced will all types of radios both wide band and narrow band.

      what's to compensate for all the varied incoming voltage levels. or do you think all disc. of every radio

      has exactly 1 volt peek to peek? 


      typically i found the TKR-750 repeater to have about 4 volts peek to peek of disc. voltage/audio and the

      Quantar in wide or narrow band having almost 6 volts. this was seriously over driving the GMSK boards

      and needed to be adjusted down to 1 volt peek to peek or around that..

      over driving means R2D2, under driving means R2D2... been there Done that... made the T-shirt..


      73 -

      Tony

      NN1D







      ---In dvrptr_v1@yahoogroups.com, <mccrpt@...> wrote:

      Typically with the rcvr "window", I think you talking about bandwidth of the rcvr, it is governed by the IF bandwidth.  This is usually a crystal filter in the IF.

      Comm Spec has some crystal filters for some radios for narrow banding.

      The tx bandwidth is controlled by deviation and modulation characteristics.  For DSTAR the dev should be no more than 1.2 kHz.  If you have a pot adjustment that changes greatly with small change usually means the levels are high and need additional attenuation so the pot will work over wider range.

      73, ron, n9ee/r

      Ron Wright, N9EE/R
      BSEE
      Micro Computer Concepts
      352-683-4476
      mccrpt@...



      To: DVRPTR_V1@yahoogroups.com
      From: nn1d@...
      Date: Sun, 20 Oct 2013 10:44:54 -0700
      Subject: [DVRPTR_V1] RX Window For Commerical Radio Inerface

       
      Hello Group,

      I was wondering how does one adjust the RX window for different Commercial radio interfaces.
      Having Past Experience with Satoshi and Moen boards along with sound card interfaces, they ALL have input audio adjustments "pots" or software adjustments to compensate the different disc, levels.

      this board does not, and the typical its all done internal reason don't sit well with me

      Satoshi input level was so critical that one fraction of a turn rendered you all R2D2 with 2 different repeaters systems
      Kenwood TKR-750
      and
      Motorola Quantar

      any help? with adjustments

      Tony
      NN1D

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