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Ubitx V5 Low audio and No SSB #ubitx-help #v5

Praba Karan
 

Recently I assembled ubitx V5 in  cabinet after a year long wait in my shack.
Ubitx V5, CEC v1.2 firmware Nextion display, modified bafeong mic.

Receiver working nice but with low audio like in V4.
During just pressing PTT, ubitx consuming about 1.2 amps at 12v, but it is not varied with sound in mic. Loud ' hhhelloooo' do not vary current consumed.

Also noted  during  just  pressing PTT, my swr/power meter displaying stable power output of 3 watts. 
I checked mic bias voltage, which is 7.8 volt.

Help me to identify root cause of these issues.

Arv Evans
 

Karan

Are you using the microphone cartridge that came with your uBITX V-5?
Several people have tried to use other microphones and experienced low 
audio level (low SSB output).  Some resolved the problem by enlarging 
the hole in the microphone housing to allow more audio to reach the 
electret cartridge.  

Your 7.8 volts bias to the microphone seems about right.  

Arv
_._


On Thu, Apr 9, 2020 at 10:36 AM Praba Karan <vu3dxr@...> wrote:
Recently I assembled ubitx V5 in  cabinet after a year long wait in my shack.
Ubitx V5, CEC v1.2 firmware Nextion display, modified bafeong mic.

Receiver working nice but with low audio like in V4.
During just pressing PTT, ubitx consuming about 1.2 amps at 12v, but it is not varied with sound in mic. Loud ' hhhelloooo' do not vary current consumed.

Also noted  during  just  pressing PTT, my swr/power meter displaying stable power output of 3 watts. 
I checked mic bias voltage, which is 7.8 volt.

Help me to identify root cause of these issues.

Praba Karan
 

I am using modified bafeong speaker mic

Arv Evans
 

Karan

Those Bafeong microphones are what I was thinking about when I mentioned opening the audio hole in the case.  They are notorious for having too small a hole or having the hole offset from the microphone position.  Some persons have even replaced the original Bafeong electret element with the larger electret that came with the uBITX.

Arv
_._


On Thu, Apr 9, 2020 at 10:50 AM Praba Karan <vu3dxr@...> wrote:
I am using modified bafeong speaker mic

Evan Hand
 

Praba Karan,

If you used a different Nano to upgrade to the KD8CEC software, then you will need to recalibrate.  The calibration data from the factory is stored in the EEPROM, which is not saved/uploaded with the software.  Also, each board set is different, so you need to recalibrate anytime you change the Nano for a given board.

I would start with the BFO calibration to verify that it is correct.  I have used the following webpage with Chrome and a USB (or laptop) mic:
https://www.hfsignals.com/index.php/bfo-tuning-aid/

You want to adjust more towards the "high" side, as that reduces any carrier bleed through.  Note that the BFO should be close to 11.055500 MHz, as the SSB filter is 11.059 MHz.  For my board 11.055600 MHz was about right.

There is also the Memory Manager software from KD8CEC that I have found useful in being able to save the current settings prior to making changes, then to save again as I get closer to what I want.
https://github.com/phdlee/ubitx/releases/tag/v1.11

73
Evan
AC9TU

Praba Karan
 

Checked BFO calibration which appeared to be correct.
Both low audio and carrier leak are interconnected?

On Fri 10 Apr, 2020, 12:52 AM Evan Hand, <elhandjr@...> wrote:
Praba Karan,

If you used a different Nano to upgrade to the KD8CEC software, then you will need to recalibrate.  The calibration data from the factory is stored in the EEPROM, which is not saved/uploaded with the software.  Also, each board set is different, so you need to recalibrate anytime you change the Nano for a given board.

I would start with the BFO calibration to verify that it is correct.  I have used the following webpage with Chrome and a USB (or laptop) mic:
https://www.hfsignals.com/index.php/bfo-tuning-aid/

You want to adjust more towards the "high" side, as that reduces any carrier bleed through.  Note that the BFO should be close to 11.055500 MHz, as the SSB filter is 11.059 MHz.  For my board 11.055600 MHz was about right.

There is also the Memory Manager software from KD8CEC that I have found useful in being able to save the current settings prior to making changes, then to save again as I get closer to what I want.
https://github.com/phdlee/ubitx/releases/tag/v1.11

73
Evan
AC9TU

Evan Hand
 

They can be.  The BFO is used for both receive and transmit signals.  If the BFO is used to generate the sideband signal with the filter to remove the opposite sideband.  If the BFO frequency is too close to the edge of the SSB filter, I have seen the carrier "bleed" through.  I did tests using an RSP2 SRDPlay and the RSP Spectrum Analyzer software to see what the signal was like.  When I adjusted the BFO to minimize the carrier, the sound was tinny.  When I adjusted the BFO for a more pleasing sound, I had a residual carrier, AND the volume was lower.  The filter is fairly narrow and has sharp skirts.  This means that if not centered correctly it will cut off some of the signal.

I have performed this test on only one v4.  That was because I was having issues with that balanced BFO mixer and was trying to verify that the diodes were not the issue.

The speaker could be another reason for your low volume.  My v5 is driving a 4 ohm speaker with good results.  Both of my v4 require audio amps to drive a speaker.  Those are TDA2030 modules from eBay.

Above is my analysis.  It could be in error.  You can wait to see if others have any suggestions.
73
Evan
AC9TU