Cw 100r updating
To minimize, the phase differences in both channels, C71 and C73 are replaced by 0R resistors.
The harmonics of the display PWM dimming schemes can cause interference.
This meant: depending on drive level, the PA section could in addition to the desired signal emit its own oscillations around 1MHz. The reason is that at the output of the LM2931 a minimum load is required to safely reach the "0V".
As a result, the quiescent current consumption in "off" mode has now fallen to less than 1u A. ) The following changes are necessary: Here are the required pictures If you have old UI board (rev.This SWR measuring bridge is reliable throughout the operating range of the MCHF.To make it possible to exchange boards with other users, we should agree on a consistent use of the male and female connectors.and it is not easy to short them) To prevent damaging the STM32F4 with static (dis)charges on the keyer lines and on the PTT line two zener diodes of 3.3v should be connected at those lines towards ground.
These signal lines can be found on pin 12 and 13 on the ui board (and the diodes can be directly soldered to the board at those pins) The two gate resistors R81 and R82 were of 220R can be reduced to 100R (only if the amplifier has self oscillatiion at high output levels).
Next to it is the "correct" line: the MAIN PAGE of the bridge that goes to the BNC connector.