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Baofeng microphone mod for BITX

John M
 

All, 

This is a work in progress document for modifying a Baofeng microphone for the BITX40.

https://drive.google.com/file/d/0B8v7bRFPZV71U3BVR28zUEdkN2M/view?usp=drivesdk

It uses the element included in the kit.

Feedback is appreciated.

73's

John

KF6EFG

Daniel Acevedo
 

This is exactly what I was looking for! You did a nice job. Does this actually work? Does it key up when you press the PTT?

John M
 

It does key up when the PTT is pressed.  

I wanted to use a microphone that was pretty much prebuilt, and would allow for the BITX condenser.  

I have yet to make a contact on it, because I don't have a proper antenna for 40.

As soon as I can get up on my roof, you know one is going up!


Mike Yancey
 

I'm curious why you replaced the Microphone's electret 'capsule' with the one provided in the kit?
Aren't these mic's all electret anyway?

I've bought a couple of these on eBay - one for an ACTUAL Beofeng radio and another for ... 'experimentation' just like this, so I appreciate your work!

I've found them for as cheap as USD$2.89. Quality: be prepared to repair.
The first one I bought - worked perfectly.
The second - PTT is fine, Speaker fine... No transmit. Solution: solder a little piece tinned buss wire to join the electret in. Bad solder join or bad PCB trace.
Link: https://mikeyancey.com/heres-what-2-89-will-buy/

This is a SUPER idea, BTW. The BitX20 kit I have has a 4-pin (old) Kenwood-style connector, which indeed, will support a Speaker in the Mic.

Mike Yancey, KM5Z
Dallas, Texas, USA

John M
 

Mike,

I used the BITX condenser for a couple of reasons:

1. It came with the BITX, so I know that it is a working unit.

2. It fit in the microphone shell without modification.

3. I could not use the PC board used in shell because it uses a common ground, and the BITX does not. Wiring up the condenser is trivial when compared to having to reconfigure the board.

Thanks for the source to mic's... Wish I had it when I bought this one!

Thanks for all the feedback.

John McGrath, KF6EFG

Brian D. K2BRZ
 

Just assembled my kit and am having trouble with my Baofeng mic, this is perfect. Thanks for posting!


Just have to fix a minor wiring slip up for the raduino and put the antenna up and I should be okay.


Brian

K2BRZ

Andrew Mason
 

Hi,

I am also using a Baofeng microphone on my BITX40, it is the microphone designed for the UV5R that I also have.  

I use the microphone "as is" - not modified. This way I can use the microphone on both radios :-)

I am a little confused as to why there is a need to re-wire the Baofeng microphone ???  

It is just a matter of making the right connections back to the BITX40 cables that are supplied with the BITX40 kit.

The standard insert with the Baofeng microphone is fine, and sounds great.  The wiring diagram showing how the cables need to be connected is attached below.


Image result for baofeng microphone pinout


73

Andrew

VK4JAM

College Professor Simon Thompson <nwccenglishprofessor@...>
 

I made the connections from the BitxX40 to the Baofeng microphone without any modifications. It works perfectly, and I don’t know why anyone would go to the trouble of rewiring the mic if it weren’t a sheerly technical exercise.

I can provide a sense of the connections, but I suspect the wire colours are different for each batch of Baofeng pics.

On Apr 17, 2017, at 6:59 AM, kd2iog@... wrote:

Just assembled my kit and am having trouble with my Baofeng mic, this is perfect. Thanks for posting!


Just have to fix a minor wiring slip up for the raduino and put the antenna up and I should be okay.


Brian

K2BRZ


College Professor Simon Thompson <nwccenglishprofessor@...>
 

I literally wrote the connections down on the back of an envelope. I will open up my radio and figure out what I did.

On Apr 17, 2017, at 9:33 PM, College Professor Simon Thompson <nwccenglishprofessor@...> wrote:

I made the connections from the BitxX40 to the Baofeng microphone without any modifications. It works perfectly, and I don’t know why anyone would go to the trouble of rewiring the mic if it weren’t a sheerly technical exercise.

I can provide a sense of the connections, but I suspect the wire colours are different for each batch of Baofeng pics.
On Apr 17, 2017, at 6:59 AM, kd2iog@... wrote:

Just assembled my kit and am having trouble with my Baofeng mic, this is perfect. Thanks for posting!


Just have to fix a minor wiring slip up for the raduino and put the antenna up and I should be okay.


Brian

K2BRZ



Craig Wadsworth <cwadsworth@...>
 

Andrew,
Thanks for sharing the nice graphic.
I have several Baofeng speaker / mics and headsets. This will help.
Regards,
Craig




Craig Wadsworth, ATP, RET, PE
Illinois Assistive Technology Program

Brian D. K2BRZ
 

Mic and switch are working fine, just need to hang the antenna and I'll be good to go!


Brian

K2BRZ

amer1337@...
 

I tried using the baofeng electret mic, jumping leads to go right to the consensor so the ptt and mic dont share the same ground and if i whistle into the mic it puts power out but not while talking.

DJ4MU
 

Despite the posted diagram i'm still not sure how to wire up the unmodified Baofeng mic to the Bitx.

the speaker connections seem obvious, with ground on the sleeve of 2.5mm and other speaker connection to tip.

the mic + connection seems fairly obvious too , on the ring of the 3.5mm.

But where are the mic - and PTT wires from the Bitx connected, and do they all use the same ground?

Which Bitx wire connects to the tip of the 3.5mm (v+) ?

 

DJ4MU, and All, 

While I didn’t try too awful hard to figure out how to make my Baofeng work UN-modified, I was not having much luck, so having a handful of these on hand, I just opened one up, disconnected the speaker, cut traces, removed SMD devices and made sure the PTT and the MIC wiring and traces went only to the devices and indicated pins, while retaining only the shortest possible runs.  I also made sure my jacks were mounted to plastic and not grounded to a metal chassis.  I also drilled out the tiny hole in front of the mic element. 

I used two Radio Shack square panel jacks to plug mic plug into.  If you turn the flat sides against each other that are 180 degrees away from the solder rings on the jacks, then the mic plug will slide into place perfectly.

So, while my mic is not interchangeable any more with my Baofeng HT, I sure don’t care, as it fits my description of a junk box find @ under $5. And the jacks are part of my multi hundred part cleanup of multiple Radio Shacks.
Below is my prototyping set up.

KM4YEC
Craig





On May 28, 2017, at 5:09 AM, DJ4MU <pbepler@...> wrote:

Despite the posted diagram i'm still not sure how to wire up the unmodified Baofeng mic to the Bitx.

the speaker connections seem obvious, with ground on the sleeve of 2.5mm and other speaker connection to tip.

the mic + connection seems fairly obvious too , on the ring of the 3.5mm.

But where are the mic - and PTT wires from the Bitx connected, and do they all use the same ground?

Which Bitx wire connects to the tip of the 3.5mm (v+) ?

<Bao_plug_Bitx.jpg>

Joe Puma
 

It showing you where the push to talk connections are which is basically the grounds of both mic and speaker connections that are connected together when you press the push to talk. So yeah basically pressing the push to talk will combine the mic ground and speaker ground. I am not sure if that will cause conflict in the radio. 


Sent from my iPhone

On May 28, 2017, at 5:09 AM, DJ4MU <pbepler@...> wrote:

Despite the posted diagram i'm still not sure how to wire up the unmodified Baofeng mic to the Bitx.

the speaker connections seem obvious, with ground on the sleeve of 2.5mm and other speaker connection to tip.

the mic + connection seems fairly obvious too , on the ring of the 3.5mm.

But where are the mic - and PTT wires from the Bitx connected, and do they all use the same ground?

Which Bitx wire connects to the tip of the 3.5mm (v+) ?

<Bao_plug_Bitx.jpg>

DJ4MU
 

After taking apart the Baofeng mic i came to the following conclusion:

3.5mm Tip - NC Ring - Mic -red Sleeve - PTT - black 2.5mm: Tip - ground -white Ring - NC Sleeve -SPKR - green

There's a LED with 1K resistor connected between PTT+ and Mic+ which i have removed to be sure. So what would contradict tying the ground leads in the BitX together and using this mic like any other 4-wire mic - or does it have to be a 6wire Design?

César EA3IAV
 

So if you have 4 wires how do you put that to a 3 pin male jack?
do you share mic and ptt ground wires? Is this gonna work?

thank you

César EA3IAV
 

I sharee ground for mic a ptt but it did not work: i heard relais working but it did not mute rx sound....

DJ4MU
 

So if you have 4 wires how do you put that to a 3 pin male jack? do you share mic and ptt ground wires? Is this gonna work?

you have 6 connectors in total on the 2 stereo plugs but only 4 wires going into the Baofeng mic from those connectors.

They all share one common ground on the 2.5mm plugs tip.

this works for me but i'm not sure if it's responsible for the noise problem i have at the moment .

so connections are:
3.5mm:
Tip - NC
Ring - Mic -red
Sleeve - PTT - black

2.5mm:
Tip - common ground (spkr/mic/PTT) -white
Ring - NC
Sleeve -SPKR - green

hope that clarifies it.

César EA3IAV
 

My problems are due to bad connections. Baofeng uses very poor quality wires and i can see copper trhough plastic!! I have to rewire it. It is going to work i guess as i have checked that ground is the same for mic a ptt on the pcb

ttanks