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#uBitx - No TX #ubitx

F8BXI
 

Hello All,

I received my uBitx 2 weeks ago and wired all the stuff. Like many others, I put a mono plug in the Speaker connector before reading it was a bad thing to do. At first, I had a weird sounding in the external speaker. I desoldered the Speaker connector and plugged directly wires to wires to an external speaker. Now, the audio is pretty good on all bands.

After playing around with the receiver, I wanted to try transmitting in CW. I plugged a straight key with a mono jack to the K connector (this one is correctly wired from the start with the resistor to avoid transmission at startup), I connected a dummy load with an HF SWR meter but I have nothing coming out. I don’t hear any CW sidetone and the SWR meter do not move at all. I did not try a microphone to transmit.

Sometime this week I will check the PCB and connections around, but I would like to know (as I understood by reading some reports on this list) if the TDA2822 has a chance to be blown ? As I still have a good audio, I do not expect this one as blown but as the TDA is used both for audio amplifier for the speaker and also for the microphone amplification, I wonder if it can also have something to do with the CW transmit ?

Thanks for any help,


73,
Philippe
F8BXI

Arvo W0VRA
 

On Tue, Mar 6, 2018 at 10:52 am, F8BXI wrote:
As I still have a good audio, I do not expect this one as blown but as the TDA is used both for audio amplifier for the speaker and also for the microphone amplification, I wonder if it can also have something to do with the CW transmit ?
Hello, Philippe.

If you have audio, then the TDA is fine.  The TDA is not used for microphone amplification, and it is not involved in CW TX.

I will leave the rest of the issue up to others with more expertise.

Jerry Gaffke
 

Since you don't hear the CW sidetone, the Raduino is probably not sensing when you press the key.
There's a blue wire from the Raduino's 8 pin connector to your keyer jack.
When you press the key, check if the voltage on that blue wire transitions from 5v to 0v. 


On Tue, Mar 6, 2018 at 10:52 am, F8BXI wrote:
I received my uBitx 2 weeks ago and wired all the stuff. Like many others, I put a mono plug in the Speaker connector before reading it was a bad thing to do. At first, I had a weird sounding in the external speaker. I desoldered the Speaker connector and plugged directly wires to wires to an external speaker. Now, the audio is pretty good on all bands.

After playing around with the receiver, I wanted to try transmitting in CW. I plugged a straight key with a mono jack to the K connector (this one is correctly wired from the start with the resistor to avoid transmission at startup), I connected a dummy load with an HF SWR meter but I have nothing coming out. I don’t hear any CW sidetone and the SWR meter do not move at all. I did not try a microphone to transmit.

F8BXI
 

Thank you for the tip. I did the test and did not have the transition from 5 to 0v. I saw that I did not connecte the ground from the connector to the PCB. When I did it, the uBitx was transmitting without any keying. So, I rewired the connector following Jim, W0EB advice and added the ground connection.

I now have the transition from 5 to 0V correct. The SWR meter is now showing around 10W on 7MHz through a dummy load.  When I push the key, LSB is switching to CW on the LCD display. But, I only hear a clic and no sidetone each time I push the key but I see the SWR meter dancing at the rhythm of my keying. 

Is it normal or not ? If not, what should I do ?

Many thanks for your help (Thank you Arvo for the precision about the TDA),


73,
Philippe


Le 6 mars 2018 à 20:42, Jerry Gaffke via Groups.Io <jgaffke@...> a écrit :

Since you don't hear the CW sidetone, the Raduino is probably not sensing when you press the key.
There's a blue wire from the Raduino's 8 pin connector to your keyer jack.following 
When you press the key, check if the voltage on that blue wire transitions from 5v to 0v. 


On Tue, Mar 6, 2018 at 10:52 am, F8BXI wrote:
I received my uBitx 2 weeks ago and wired all the stuff. Like many others, I put a mono plug in the Speaker connector before reading it was a bad thing to do. At first, I had a weird sounding in the external speaker. I desoldered the Speaker connector and plugged directly wires to wires to an external speaker. Now, the audio is pretty good on all bands.

After playing around with the receiver, I wanted to try transmitting in CW. I plugged a straight key with a mono jack to the K connector (this one is correctly wired from the start with the resistor to avoid transmission at startup), I connected a dummy load with an HF SWR meter but I have nothing coming out. I don’t hear any CW sidetone and the SWR meter do not move at all. I did not try a microphone to transmit.

F8BXI
 

Please, forgive me, I just forgot to open the audio potentiometer ;-) But There is a big pop sound in the speaker. Will see how to correct this.


Thanks a lot for your precious help. I’m looking forward to try a first QSO.

Best 73,
Philippe


Le 6 mars 2018 à 21:38, F8BXI <f8bxi@...> a écrit :

Thank you for the tip. I did the test and did not have the transition from 5 to 0v. I saw that I did not connecte the ground from the connector to the PCB. When I did it, the uBitx was transmitting without any keying. So, I rewired the connector following Jim, W0EB advice and added the ground connection.

I now have the transition from 5 to 0V correct. The SWR meter is now showing around 10W on 7MHz through a dummy load.  When I push the key, LSB is switching to CW on the LCD display. But, I only hear a clic and no sidetone each time I push the key but I see the SWR meter dancing at the rhythm of my keying. 

Is it normal or not ? If not, what should I do ?

Many thanks for your help (Thank you Arvo for the precision about the TDA),


73,
Philippe


Le 6 mars 2018 à 20:42, Jerry Gaffke via Groups.Io <jgaffke@...> a écrit :

Since you don't hear the CW sidetone, the Raduino is probably not sensing when you press the key.
There's a blue wire from the Raduino's 8 pin connector to your keyer jack.following 
When you press the key, check if the voltage on that blue wire transitions from 5v to 0v. 


On Tue, Mar 6, 2018 at 10:52 am, F8BXI wrote:
I received my uBitx 2 weeks ago and wired all the stuff. Like many others, I put a mono plug in the Speaker connector before reading it was a bad thing to do. At first, I had a weird sounding in the external speaker. I desoldered the Speaker connector and plugged directly wires to wires to an external speaker. Now, the audio is pretty good on all bands.

After playing around with the receiver, I wanted to try transmitting in CW. I plugged a straight key with a mono jack to the K connector (this one is correctly wired from the start with the resistor to avoid transmission at startup), I connected a dummy load with an HF SWR meter but I have nothing coming out. I don’t hear any CW sidetone and the SWR meter do not move at all. I did not try a microphone to transmit.


Arvo W0VRA
 

On Tue, Mar 6, 2018 at 01:16 pm, F8BXI wrote:
But There is a big pop sound in the speaker.
Yes, there is.

See http://ubitx.net/fix-audio-pop/

There are a lot of other hacks on that website.

Jerry Gaffke
 

You should hear the sidetone when pressing the key.
The sidetone comes out of the Nano on the Raduino as a 0 to 5 volt square wave 
labeled CW-TONE in the schematic. 
That square wave is low pass filtered while going through R250,251,252,253 to make it
a bit more pleasant as a sine wave, then it gets tied into the same amp as the receiver audio.

There's an error in the uBitx schematic,.  
R253 in the sidetone lowpass filter should be 220k, not 1k.
Verify that R253 really is 220k with an ohmmeter (all 4 resistors can be
measured while on the board) and that it is soldered down correctly.
Could be that R253 was a hand mod after the initial assembly of the board. 

If those four resistors look good, try driving a speaker from CW-TONE through
a series resistor of about 500 ohms to ground.  Should hear a faint tone when the key is down.
If not, either CW-TONE is shorted to ground, or perhaps that IO cell of the Raduino got blown somehow.

Jerry, KE7ER



On Tue, Mar 6, 2018 at 12:38 pm, F8BXI wrote:
I now have the transition from 5 to 0V correct. The SWR meter is now showing around 10W on 7MHz through a dummy load.  When I push the key, LSB is switching to CW on the LCD display. But, I only hear a clic and no sidetone each time I push the key but I see the SWR meter dancing at the rhythm of my keying. 
 

Jerry Gaffke
 

Ah, good.   I assume you now hear the sidetone when transmitting CW.

There have been many many discussions about that pop in this forum going back years.
Here's a recent solution from VA7AT, documented by ND6T, looks promising:
    https://groups.io/g/BITX20/message/43322
 

Jerry, KE7ER


On Tue, Mar 6, 2018 at 01:16 pm, F8BXI wrote:

Please, forgive me, I just forgot to open the audio potentiometer ;-) But There is a big pop sound in the speaker. Will see how to correct this.
 

F8BXI
 

Hi All,

Just to let you know that thanks to your help, I confirmed my first QSO yesterday evening with FY5KE in CW (439/439). Cndx: uBitx around 10W, trap dipole in attic.

Bet 73,
Philippe


Le 6 mars 2018 à 22:32, Jerry Gaffke via Groups.Io <jgaffke@...> a écrit :

Ah, good.   I assume you now hear the sidetone when transmitting CW.

There have been many many discussions about that pop in this forum going back years.
Here's a recent solution from VA7AT, documented by ND6T, looks promising:
    https://groups.io/g/BITX20/message/43322
 

Jerry, KE7ER

On Tue, Mar 6, 2018 at 01:16 pm, F8BXI wrote:

Please, forgive me, I just forgot to open the audio potentiometer ;-) But There is a big pop sound in the speaker. Will see how to correct this.