Re: Very low ssb output for v5
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Evan, please study thevpost? PA? lpf for 40m band. Let us take sch values as correct. Tro take out the coils one by one? ( you can do without removing the board) and check for inductance and do some trimming. The 40m band power increases. All the best Sarma vu3zmv
On Mon, 13 Jan 2020, 10:57 am Evan Hand, < elhandjr@...> wrote: To answer your request for the voltage measurements, You can use the v4 values for the SSB transmit side, as there are only minor differences.? The audio receive and bandpass filters are the significant differences, with only the audio section being able to be measured with a volt meter. There is a change in the IF/SSB filter frequencies, however this again will not show up in voltage measurements.
/g/BITX20/files/VU2ZAP/uBitx4%20voltages.xlsx
To help, download the v4 and v5 schematics to compare.
If you compare the two, you will see that the Q6 mic preamp sections are the same.
The most likely issue for low SSB transmit power after the BFO calibration is the mic gain.? There have been varying reports on the supplied mic performance.? Most have required a preamp to boost the signal.? On the three that I have built, I have found the provided mic to be inadequate to drive to full power without distortion.?
Hopw\e this helps and have fun!
73
Evan
AC9TU
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