[arm-allstar] How do you determine proper Rx resistor values

[Krys Beal]

Thanks Doug. I'll pick up a couple of 50K pots. Is the 10uF capacitor that
is also listed a fixed value?

On Mon, Feb 27, 2017 at 10:44 AM "Doug Crompton via arm-allstar" <
arm-allstar at hamvoip.org> wrote:

> Krys,
>
>   Resistor values have nothing to do with the Nano but rather the audio
> in/out of the USB audio FOB which would be used in conjunction with the
> Nano for control. The audio is adjusted with the RX/TX gains in
> simpleusb-tune-menu and both have a range of 1 to 999 with a median value
> of 500. The default values are set to 500 when you initially setup. In
> addition there is a parameter in simpleusb-tune-menu called rxboost which
> can boost the level by 20db when on. It is on by default.
>
> It is also important to note that RX is what the node radio receives when
> you transmit to it from another radio and TX is what you hear on that radio
> when your node is transmitting. So you have to look at it in the
> perspective of the node radio not the radio/handheld, etc. you use to talk
> to your node.
>
> Because there are so many different radios and sound FOBs used with Allstar
> it often becomes necessary to add additional attenuation in the form of a
> resistor or resistive divider in series with the audio leads. Unfortunately
> there is no list of values for a particular combination. I would start out
> with 10K on both the TX and RX sides. If the simpleusb-tune-menu audio
> settings are no pegged or very close to one extreme or the other then you
> are probably OK. At least one commercial FOB has pots and that might be a
> way to go. Use a couple of 10K or higher pots on the TX and RX lines and
> with the SW values set at mid point adjust the pots. Then you have plenty
> of SW adjustment if you desire.
>
> If you want to use fixed resistors I would start out with 10K. For the
> Baofeng 888 we use 10K for both the RX and TX and it works out well keeping
> the settings within +-200 of the midpoint. Put the resistors in a place
> where they can easily be changed if necessary.
>
> I hope that did not confuse you. If you have any more questions let me
> know.
>
>
> *73 Doug*
>
> *WA3DSP*
>
> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
>
> On Mon, Feb 27, 2017 at 9:04 AM, "Krys Beal via arm-allstar" <
> arm-allstar at hamvoip.org> wrote:
>
> > I've recently purchased the preassembled HamVOIP Nano interface. While
> > looking at the Rx portion of the interface schematic there is a note
> > indicating that resistor values indicated are for the DMK URI, and should
> > be adjusted for my specific application. My plan is to use a TH-9000D
> > modified per the writeup on the HamVOIP website. How do I determine the
> > proper resistors to use for this application.
> >
> > 73
> > Krys Beal
> > K3EAL
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> >
> >
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