Dan W2DLC ordered his µBITx on December 29, 2017 and received it on March 2, 2018.
It was a version 3 with the WX branded TDA2822 audio chip.
(1) By the time he was ready to assemble it, Ron, W7HD had posted a fix using a voltage regulator. This was his first mod and he has had good working audio since then.
(2)The second mod he implemented was installing the KD8CEC firmware which was more intuitive for me and solved some issues such as keying responsiveness.
(3) The third mod was to add a short USB cable from the Arduino Nano to allow data access outside the case.
(4) The fourth mod was adding the click-pop suppression kit from Don ND6T, Wayne VA7AT, and kitted by Kees K5BCQ.
(5) The fifth mod was the RF output peaking mod suggested by Howard Fidel WB2VXW
(6) The sixth mod was the ND6T AGC kit that he got from K5BCQ at the same time as the click-pop kit. When he installed the AGC kit, he used Kees’s installation suggestions for mounting it on the main board. He also added an RF attenuator/gain control as suggested by ND6T, and hooked a wire from J1 to the purple analog wire on the Raduino to provide an S meter.
(7) While he had the board on the table, R250 was changed to 100K to reduce the sidetone level and C1 cap was replaced with a 1μF to shape the CW note.
(8) Then the relays were changed out for Axicoms as suggested by Mike W0MNE, to reduce harmonics when using SSB on the lower HF bands.
(8) Finally, he replaced L7 and L5 with SMT inductors as suggested by Raj VU2ZAP to reduce spurs on the higher HF bands.
Dan is very happy with how well my uBITX functions at this point. He has placed it in a small Apache case behind an aluminium faceplate that he fabricated. The whole thing is pretty rugged and works well with a three cell 18650 battery pack.
Dan says he finally has the spy radio he has always wanted.