[arm-allstar] chinese mobile radio??

[Doug Crompton]

It is perfectly OK to use the DC audio input pin with a blocking cap and
the proper resistive divider on the DMK-URI. That is why it is there, to
add that flexibility and that is why the ARA boards block DC and use a
modest series resistor on the input and output leaving it to the user to
use a simple resistive divider if necessary. The FOB board should not
assume some input or output values but rather leave the individual the
flexibility to adapt it to any use. Some people use low level discriminator
input and others take the RX audio off of a speaker.

Am important thing especially when you are driving longer cables or around
noise is to have the most possible level at the source without distortion
and attenuate that level at the destination. This gives the best signal to
noise ratio in most cases.


*73 Doug*

*WA3DSP*

*http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*

On Fri, Apr 26, 2019 at 10:19 PM "B Harvey via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Kevin,
>
>    I'm not sure of the exact revision. I do know that every attempt to use
> pin 21 fro input has resulted with audio that was too low to properly drive
> my node and I've had to use pin 9 with a DC blocking capacitor regardless
> of the radio used. Using pin 9, I have been with the capacitor I've been
> able to use both a Baofeng UV 82 and an Alinco DR 435 MK3.   After
> initially setting my levels, I've received reports of good audio and my
> DTMF command have worked without a problem.
>
>
>
> Brian / KK6DOQ
>
> On Fri, Apr 26, 2019 at 5:31 PM Kevin Custer <kevin at kc-wireless.com>
> wrote:
>
> > Brian,
> >
> > By chance is the DMK URI you have and newer "URIxB"?  If so, the
> > hardware has been redesigned to provide less attenuation in the audio
> > path when using pin 25.  This is a requirement to make the URIxB have
> > the same RX audio level as compared to a URIx.  This was accomplished by
> > changing the value of R5 (previously a 470k) to a 39k.
> >
> > Kevin W3KKC
> >
> > On 4/26/2019 6:12 PM, "B Harvey via ARM-allstar" wrote:
> > > John,
> > >
> > >     I connected mine to a DMK-URI USB audio adapter before connecting
> to
> > the
> > > RPi. For the most part, it was a direct pin to pin connection between
> the
> > > Alinco DB9 and the URI DB25 with the exception of one DC blocking
> > capacitor
> > > at pin 9 of the DB25. For some reason, the standard input on my URI
> > doesn't
> > > have enough gain on the standard receive pin. I can provide the pin
> > wiring
> > > I used if you'd like.
> > >
> > >
> > > Brian / KKDOQ
> >
> >
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