Can anyone report on the power output transmitting in SSB at a level before distortion starts.
I couldn't get any decent audio with the original firmware. I tried a different microphone (that works with my FX-4CR). Increasing the mic gain
showed distortion and oscillation.
After installing the 64bit version of W9JES I have a clear modulation but less than a watt output.
I would like to know what is the power output that others reach in SSB without distortion. And if possible what is the level of the audio signal
?at the input of the audio IC WM873, at the collector of Q1 before you reach distortion ( or oscillation).
After installing the W9JES firmware this seems to be the last hurdle I have with the sBitx.

Thanks for any useful information on this subject.

?There are a few discussion topics on this subject. The primary solution to begin with is to replace the electret microphone insert with one that has a sensitivity of at least -24db, the part number I used and found on a well known auction site is AOM-5024-HD-R
It made a huge difference and I only needed the mic gain setting at about 27 once fitted to get near full power out without distortion.
If you connect a dummy load to the antenna and then key the microphone without speaking you should see a straight line until you speak, thats a crude but effective way to ensure that only your voice is being picked up by the microphone audio system. Worked for me
Regards
Paul G0KAO

Paul,?

thanks for hint. Do not know where you got it but Mouser has?AOM-5024L-HD-R where I am not sure what the “L” means but it has 24dB sensitivity at 2.2kOhms.
rgds,

--
Petr?

开云体育

DigiKey has them for a little over $3 each. ?

Thank you Paul.
Unfortunately in my case it is not the mike. I tried different microphones and also with an external amplifier/equalizer/compressor and that didn't help.
That is why I would like to know the AC voltage at the output of the transistor Q1 to have a starting point in debugging. There is nothing else between the mike and the WM873.
As mentioned since installing the W9JES firmware at least the audio is good but hardly going above one watt.
The 2Tone power output is about 17w in a dummy load.
I didn't yet measure the output of Q1 but will do soon.

On Sun, Mar 31, 2024 at 12:29 PM, Yvon AE7YD wrote:

Thank you Paul.
Unfortunately in my case it is not the mike. I tried different microphones and also with an external amplifier/equalizer/compressor and that didn't help.
That is why I would like to know the AC voltage at the output of the transistor Q1 to have a starting point in debugging. There is nothing else between the mike and the WM873.
As mentioned since installing the W9JES firmware at least the audio is good but hardly going above one watt.
The 2Tone power output is about 17w in a dummy load.
I didn't yet measure the output of Q1 but will do soon.

Have you tried a USB microphone to see if you get better results?? I released an app to use USB input devices in Toolbox v2.2. Since you are using my build, you can do this to update Toolbox on the beta build using terminal.

Thank you JJ, I'll try tomorrow and will let you know.

I did do the uninstall/install successfully.? I selected the USB mike from the Toolbox but I missed something as I don't get any audio.

I missed to reboot. There is a latency between me talking and the output. More tomorrow.

After re-soldering Q1 and the surrounding resistors my sBitx is finally working in SSB.
I had a few QSOs with no complain about my modulation. Had a QSO on 20m? with a station in Alberta, Canada with my FT-710
at 100 watts and received a 59 report. Switched to the sBitx (about? 7 watts) and received a report of 55 to 56. No complain about the modulation
using my ABBREE AR-780 microphone.
Installing W9JES software also made a huge difference, thanks JJ.