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Re: [tracker2] Re: OT2 TX Audio Level - How to reduce below factory level

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  • Scott Miller
    Yeah, I d probably go with 10k. Partly because that s what we have bins of here in the shop. That was what we used on the OT1 and they worked fine. Scott
    Message 1 of 5 , Apr 25, 2012
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      Yeah, I'd probably go with 10k. Partly because that's what we have bins
      of here in the shop. That was what we used on the OT1 and they worked fine.

      Scott

      On 4/25/2012 9:09 AM, Edward wrote:
      > Scott,
      >
      > If I use a potentiometer as a voltage divider do you have a suggestion
      > for the value used. I saw this article on the Sparkfun website that
      > reccomends using something between 1k Ohms and 10k Ohms (excerpt and
      > link below). Do you think a potentiometer in that range is a good choice?
      >
      > Excerpt from Sparkfun site:
      > "Because the output voltage depends solely on the ratio of R1 to R2, you
      > could use a number of different R values to get the same output (for
      > example, if R1 = R2, the output will always be half of the input,
      > whether R is 1 Ohm or 1M Ohms). For most of our purposes, the total
      > resistance (R1 + R2) should be between 1k Ohms and 10k Ohms. Less than
      > that and the circuit will waste a lot of power flowing through R1 and R2
      > to ground. More than that and Vout may not be able to source enough
      > current to drive an analog input."
      >
      > Link to sparkfun site:
      > http://www.sparkfun.com/tutorials/207
      >
      > --- In tracker2@yahoogroups.com <mailto:tracker2%40yahoogroups.com>,
      > Scott Miller <scott@...> wrote:
      > >
      > > Sure, another resistor in series should work. If you use a
      > > potentiometer, I'd set it in voltage divider mode, with one leg tied to
      > > ground, the other tied to the tracker's audio out, and the center tap
      > > being your output.
      > >
      > > Scott
      > >
      > > On 4/25/2012 8:20 AM, Edward wrote:
      > > > I believe that I may need to reduce the TX Audio level below the range
      > > > that is available in the factory configuration. I do not have a
      > > > deviation meter however the only way I can get my transmitter
      > > > (Radiometrix SHX1) to work is with the "HI" jumper off and the TX Level
      > > > set to min. so I suspect that It should be lower still. I am working on
      > > > obtaining a deviation meter. In the meantime...
      > > >
      > > > I see that there is a 100k resistor in the TX Audio Line. Would an
      > > > effective way to reduce the transmit audio level be to add another
      > > > resistor in series with the 100k resistor already in place? If so what
      > > > value of resistor would you suggest? Would a "variable resistor" be a
      > > > good choice (that way I can adjust as required)? or would a voltage
      > > > divider circuit with two resistors work better (than just adding
      > another
      > > > resistor in series?
      > > >
      > > > I saw this discussion and I think he might have had the same or
      > similiar
      > > > issue.
      > > > http://groups.yahoo.com/group/tracker2/message/6886
      > > >
      > > > Edward
      > > > KE7MWY
      > > >
      > > >
      > >
      >
      >
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