[arm-allstar] Baofeng COS without opening the radio

KD2NFC, Joe Puma kd2nfc at gmail.com
Mon Mar 4 09:07:51 EST 2019 

Interesting. So you’re saying that there is voltage on the baofeng speaker output from the opamp?  Boy I should of testing that on a baofeng I have setup for aprs and winlink. Also curious why you didn’t use a octocoupler to do the switching so it’s not electorally connected. I actually didn’t examine the circuit yet but good work never less. 

Joe
KD2NFC 

 

Sent from my iPad

> On Mar 3, 2019, at 10:35 AM, Doug Crompton via ARM-allstar <arm-allstar at hamvoip.org> wrote:
> 
> Rick,
> 
> The DMK URI's have actually gone up in price. The ham version is now $85!
> Within US shipping would bring this to the low to mid $90's.  This would
> probably be over $100 total price for AU. I don't have a reason for it
> other than greed. The URI product is over designed for what is needed for
> Allstar. With the SW low pass in our code you don't need it in hardware.
> The parts are rather inexpensive with the CM119B coming in at less the
> $1.50 in quantity.  The new URI's are now using the CM119B which has some
> different specs than the previous CMEDIA chips. It has lower output levels
> which makes it hard to use without some additional amplification on some
> radios. The DMK board has an additional opamp that can be implemented but
> as it stands in the current schematic it only has a gain of about 2. They
> have not updated the schematic as it still shows the CM119A. The ARA boards
> also use the CM119B chip and have an additional opamp to compensate for the
> lower output in the rev2 boards which will be out soon.
> 
> 
> *73 Doug*
> 
> *WA3DSP*
> 
> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
> 
> On Sun, Mar 3, 2019 at 5:16 AM "Richard Perks via ARM-allstar" <
> arm-allstar at hamvoip.org> wrote:
> 
>> Yes Doug. I'm trying that with the rims from George. It's been 2 weeks and
>> nothing received yet and there's no tracking. I'm still optimistic. What
>> blows me away is the difference in price between the very cheap fobs USD 3
>> v DMK @ 75. How can there be such a difference and DMK still have a market
>> ?
>> 
>> On Sun, 3 Mar 2019, 17:44 "Doug Crompton via ARM-allstar", <
>> arm-allstar at hamvoip.org> wrote:
>> 
>>> Rick,
>>> 
>>>  I am told from a reliable source that if you use US mail first class
>> mail
>>> NOT priority, Not UPS or FEDEX  the shipping to AU is quite reasonable.
>>> 
>>> 
>>> *73 Doug*
>>> 
>>> *WA3DSP*
>>> 
>>> *http://www.crompton.com/hamradio <http://www.crompton.com/hamradio>*
>>> 
>>> 
>>> On Sat, Mar 2, 2019 at 11:28 PM "Richard Perks via ARM-allstar" <
>>> arm-allstar at hamvoip.org> wrote:
>>> 
>>>> Thanks for posting this up Steve - Looks very interesting as I'm
>> looking
>>> to
>>>> reduce the cost of building a node. The DMK URiX RIM works well but
>> with
>>>> the high cost of shipping from the US to Australia it's very expensive.
>>>> I've ordered up some different types with cheaper shipping but wanted
>> to
>>>> try the super cheap to compare. My problem is I don't know the first
>>> thing
>>>> about how to etch. Any chance you could point me in the right direction
>>>> please ?
>>>> 
>>>> 73
>>>> Rick
>>>> VK4HC
>>>> 
>>>> On Sun, 3 Mar 2019, 11:55 "Steve via ARM-allstar", <
>>>> arm-allstar at hamvoip.org>
>>>> wrote:
>>>> 
>>>>> I have put together a little circuit that allows connection to a
>>> Baofeng
>>>>> UV-5R HT providing COS without having to open and modify the radio
>>>> itself.
>>>>> This works great for AllStar, packet, APRS, or most anything that
>>>> requires
>>>>> a soundcard connection to the radio complete with COS. I have even
>> used
>>>>> this circuit without the sound card to connect to an RC-210 repeater
>>>>> controller.
>>>>> 
>>>>> I built the circuit based on the schematic of the UV-5R but I believe
>>>> most
>>>>> of the Chinese radios will work with it. I have tried it on several
>>>>> different Chinese radios including the Anytone AT-D868UV DMR radio
>> and
>>>> they
>>>>> all worked fine. However, even though these radios are mimicking the
>>>>> Kenwood two prong speaker/mic connector, this circuit will not work
>> on
>>> my
>>>>> Kenwood TH-F6. This is due to the fact that the Chinese radios do not
>>>> block
>>>>> the DC of the audio amp from reaching the headset, which is why you
>>> hear
>>>> a
>>>>> pop when the squelch opens and closes on these radios, and is what
>> this
>>>>> circuit counts on to turn on Q1 and provide COS. The Kenwood doesn’t
>>> work
>>>>> (or have the pop) because it has a blocking capacitor and an MOS
>> switch
>>>> in
>>>>> the audio line that prevents the DC from coming out the jack. But I’m
>>>> much
>>>>> happier using a $35 radio for this purpose anyway.
>>>>> 
>>>>> I’ve hand etched a couple of boards for it so far and may send it to
>> a
>>>>> board house to make some prettier boards, especially if others are
>>>>> interested in it (I’ve already quoted them and its just too pricey
>> for
>>>>> small quantities, which is why I decided to hand make the few I
>>> needed).
>>>>> The boards I have made have some extra pads on the end to allow
>>> soldering
>>>>> directly to the audio jacks of one of the EBay sound FOBs, just makes
>>> it
>>>> a
>>>>> bit cleaner than having to cable that side of it, though it still
>>>> requires
>>>>> the two jumpers to the GPIO lines on the sound chip. Also note that
>>> there
>>>>> is an extra connection at Pin 4 on the sound card side that should
>>> allow
>>>>> using with an RA-35 or similar that already has the open collector
>>> driver
>>>>> for PTT. I have not tried this on an RA-35 but feel confident it
>> would
>>>>> work, my target was primarily the CM108 open board sound FOB you can
>>> get
>>>> on
>>>>> EBay and Amazon.
>>>>> 
>>>>> 
>>>> 
>>> 
>> https://www.ebay.com/itm/CM108-USB-Drive-Free-Sound-Card-Laptop-Computer-External-Sound-Card-Module-New/263928310585?hash=item3d735a6b39:g:SSwAAOSwEVlcDcAU:rk:1:pf:0
>>>>> 
>>>>> Also note there is no activity detection nor time out timer in this
>>>>> circuit, so I leave the TOT of the attached radio set to something
>>>>> appropriate in case things get hung up in transmit. And as with other
>>>>> interfaces, make sure to keep the RF from the attached HT from
>> getting
>>>> back
>>>>> into the RPi.
>>>>> 
>>>>> Schematics, some pictures, and this doc can be found here, hope it
>>> helps
>>>>> someone.
>>>>> 
>>>> 
>>> 
>> https://www.dropbox.com/sh/lrv9uwkgx8tpm6y/AAD2syTNpZDwcjX1gA8zjV9Va?dl=0
>>>>> 
>>>>> Steve – WB4BXO
>>>>> http://www.stevemobley.com
>>>>> _______________________________________________
>>>>> 
>>>>> ARM-allstar mailing list
>>>>> ARM-allstar at hamvoip.org
>>>>> http://lists.hamvoip.org/cgi-bin/mailman/listinfo/arm-allstar
>>>>> 
>>>>> Visit the BBB and RPi2/3 web page - http://hamvoip.org
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