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#ubitx #v6 Internal Microphone wiring on provided hand mic #ubitx #v6

Smitty, KR6ZY
 

Can someone tell me how their hand mic is wired, the one provided with the uBitX v6?  It looks like the speaker is in series with the ground wire on mine, and I'm trying to figure out if that's expected.

There's a board inside the hand mic.  It has terminals for Mic, PTT, GND, and Spk.  The mic connector on the uBitX doesn't have speaker signals, so we care about the Mic, PTT and GND.  The 3.5mm TRS mic connector should be wired as:
  • Tip: Mic, red wire
  • Ring: PTT, black wire
  • Sleeve: GND, white wire
In my speaker mic, the GND terminal is connected to a green wire, which is cut-off inside the 3.5mm connector, it doesn't go anywhere.  Instead, the white wire is connected to the Spk terminal.  The other side of the speaker is connected to ground.

For PTT, this just effectively adds about 8 to 16 ohms to the ground side, but against the 10k-ish pull-up on the other side, its still plenty low to register.  So PTT works fine.

But this also puts 8 to 16 ohms in series with the mic signal.  Looking at the mic circuit in the uBitX schematic, that shouldn't matter TOO much.  The rest of the circuit is 4.7k, 2.2k, and 10k.  So 16 ohms should be noise floor compared to those impedances.

Having said that, my uBitX doesn't want to put out power on SSB.  I key up, but my meter doesn't register any power.  If I key up CW, it registers power just fine.  But not on SSB.  I don't THINK this is the cause, but I'm putting the question out to see if anyone else is having a similar problem, or whether their mic is similarly wired.

Thanks!

73 de KR6ZY
-Mark

joshuaclough@...
 

I'm also curious about the wiring...
Is the included mic a stock Baofeng mic or has it been modified for the ubitx?

Mike WA0YCN
 

Here’s a picture of the stock Baofeng microphone I use on my v5 before I connected it. 


I removed the capacitor (C2) and resistor (R1) between the (positive) electret microphone lead and ground - these are not needed (or wanted). Then I connected red for mic, yellow for PTT, and blue for ground. Green has no connection.


Also, these wires are extremely fragile - if you’re not having any voice modulation, you might check continuity from the solder point of the red wire and the tip of the plug. 

AndyH
 

On Mon, Jan 20, 2020 at 06:39 PM, Smitty, KR6ZY wrote:
Having said that, my uBitX doesn't want to put out power on SSB.  I key up, but my meter doesn't register any power.  If I key up CW, it registers power just fine.  But not on SSB.  
Mark,

   Are you talking into the mic when you press PTT on SSB?  The radio won't generate an output signal without sound going into the mic.

   Fingers crossed!
    Andy KG5RKP

Smitty, KR6ZY
 

Yep. The whole “testing testing, Kr6zy, haaaaaaallooooo” routine. Doesn’t even twitch the power meter. 

On Jan 20, 2020, at 6:40 PM, AndyH <ahecker@...> wrote:

On Mon, Jan 20, 2020 at 06:39 PM, Smitty, KR6ZY wrote:
Having said that, my uBitX doesn't want to put out power on SSB.  I key up, but my meter doesn't register any power.  If I key up CW, it registers power just fine.  But not on SSB.  
Mark,

   Are you talking into the mic when you press PTT on SSB?  The radio won't generate an output signal without sound going into the mic.

   Fingers crossed!
    Andy KG5RKP

Smitty, KR6ZY
 

Mine has definitely been modified because it’s supposed to only connect the mic not the speaker. UBitX is a 3 pin mic connector, but the BaoFengs by default are 4 pin, adding a pin for the speaker. 

But I would expect the modifications to be made at the 3.5mm end, not inside the hand mic. If that was the intention, then they cut the wrong wire on mine.

-Mark

On Jan 20, 2020, at 5:04 PM, joshuaclough via Groups.Io <joshuaclough@...> wrote:

I'm also curious about the wiring...
Is the included mic a stock Baofeng mic or has it been modified for the ubitx?