[arm-allstar] Baofeng COS without opening the radio

[Doug Crompton]

OK, First the good news. This clearly works on the UV82.  With a 47K load
resistor the voltage out is above 2V on signal reception and 0 volts on no
reception.

The bad news is that on the 888 it appears to be capacitively blocked. On
initial key it ramps up to over 1.5V but then in about 5-10 seconds of
steady signal it goes back down to zero. There were many iterations of the
888 and it is possible some versions are OK but if any don't work it is not
a good fix.

There are several options here and I have not discussed it with George
since these findings. I doubt we will want to pursue this unless we take
the 888 out as a purchase item offering only the UV82 in the Yellow box.
The idea is to make the modification easier but if the 888 does not work
that leaves the alternative UV82 and UV5R. The UV5R is about twice the
price of the 888 currently $24 at Amazon and the UV82 slightly more. They
do offer dual band operation which the 888 does not have.

I have two major concerns about this mod in general. One is the fact that
it is just poor engineering that this is happening at all. There should be
an internal blocking capacitor. I hope it is not just bad caps leaking!
Should Baofeng decide to add a cap on a future model the method is gone.
The other issue is that the volume is not fixed and you cannot monitor the
frequency by just turning up the volume independent of the Allstar level. I
could possibly live with this problem but without COS the 888 is not going
to work.

I am not saying this would not be a reasonable method now for certain
Baofeng radios but there is no guarantee this will work in the future. I am
not sure what George will want to do regarding the manufacture of anything
on this knowing the 888 will not work but I will be talking to him in the
next few days about it.


*73 Doug*

*WA3DSP*

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



On Mon, Mar 4, 2019 at 2:25 PM "Steve Mobley - WB4BXO via ARM-allstar" <
arm-allstar at hamvoip.org> wrote:

> Fred, I don’t have a 888 but I have an 82 that it works fine on. I believe
> it to be a characteristic of most of the Chinese radios.
>
> Steve Mobley - WB4BXO
> --- hello, I am an iApp-oholic...
>
> > On Mar 4, 2019, at 1:46 PM, Steve Mobley - WB4BXO via ARM-allstar <
> arm-allstar at hamvoip.org> wrote:
> >
> > I put a marker on my knob at about 7 o’clock when off and turn it up to
> about 12 o’clock then set the level in simple-usb-tune to get the level
> between 3 and 5. Moving the volume plus/minus even 1 or 2 hours didn’t make
> much different. I also found it to decode the DTMF quite well, I was
> initially afraid the audio might not be clean enough but had no problem.
> >
> > Steve Mobley - WB4BXO
> > --- hello, I am an iApp-oholic...
> >
> >> On Mar 4, 2019, at 12:13 PM, Doug Crompton via ARM-allstar <
> arm-allstar at hamvoip.org> wrote:
> >>
> >> Fred,
> >>
> >> Yes just plug into the mic/speaker.   You are right the volume could be
> an
> >> issue. I think the best thing would be to set it and then tape or hot
> glue
> >> the volume at a specific point.  There is no reason or need to turn it
> off.
> >> That could be accomplished if necessary through an external power
> switch.
> >> The radio should NOT be run on batteries when used as a node radio. I
> will
> >> have to do a howto on this! I am thinking use simpleusb-tune-menu
> selection
> >> 2 RX volume with rxboost off. Then set the volume on the node radio for
> >> 5khz peaks while transmitting to the node radio. Then lock the volume
> pot
> >> down. Users are going to have to be responsible to do this correctly.
> >>
> >>
> >> *73 Doug*
> >>
> >> *WA3DSP*
> >>
> >> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
> >>
> >>
> >>
> >>
> >> On Mon, Mar 4, 2019 at 12:03 PM "Fred Hillhouse via ARM-allstar" <
> >> arm-allstar at hamvoip.org> wrote:
> >>
> >>> If I am understanding this correctly, Everything will just plug into
> the
> >>> MIC/SPKR ports directly. Great idea!
> >>> Will it also work on the BF-888s?
> >>>
> >>> Just be prepared for all of those that can't set the volume correctly
> or
> >>> consistently when it is turned on.
> >>>
> >>> Best regards,
> >>> Fred N7FMH
> >>>
> >>>
> >>> -----Original Message-----
> >>> From: ARM-allstar [mailto:arm-allstar-bounces at hamvoip.org] On Behalf
> Of
> >>> "Doug Crompton via ARM-allstar"
> >>> Sent: Sunday, March 03, 2019 10:55 PM
> >>> To: ARM Allstar
> >>> Cc: Doug Crompton
> >>> Subject: Re: [arm-allstar] Baofeng COS without opening the radio
> >>>
> >>> Steve,
> >>>
> >>> OK Thanks. We are already thinking about laying out a FOB board
> >>> specifically for the Baofeng's. Most of the components are already on
> our
> >>> ARA-1 board now and it would be a minimal change to make it work with
> the
> >>> Baofeng's directly.  I want to breadboard it first and we have some
> >>> speak/mic cables on order. I would say if all goes well we could have a
> >>> product out in a month. The FOB would plug into the USB and a cable
> would
> >>> plug to the FOB and the radio speaker/mic. Very easy for the user. This
> >>> will also make it easier to produce the yellow box nodes.
> >>>
> >>>
> >>> *73 Doug*
> >>>
> >>> *WA3DSP*
> >>>
> >>> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
> >>>
> >>> On Sun, Mar 3, 2019 at 10:48 PM "Steve via ARM-allstar" <
> >>> arm-allstar at hamvoip.org> wrote:
> >>>
> >>>> Certainly Doug, that's why I put it
> >
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