Re: [tracker2] Re: OT2 TX Audio Level - How to reduce below factory level
- 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.
On 4/25/2012 9:09 AM, Edward wrote:
> 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:
> --- In firstname.lastname@example.org <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
> > > resistor in series?
> > >
> > > I saw this discussion and I think he might have had the same or
> > > issue.
> > > http://groups.yahoo.com/group/tracker2/message/6886
> > >
> > > Edward
> > > KE7MWY
> > >
> > >