Known Issues - df8oe/UHSDR GitHub Wiki

• DSP NB and DSP NR function causes many strange behaviours. Buttons do react delayed, encoders do "jump" or turn sporadic wrong direction, sound gets distorted. Because of DSP NB and DSP NR do not help in most situations to get signal clearer it is recommended not to use these functions. They are highly experimental, do not work as expected and can cause many strange issues which are not easy to sort to DSP NB/NR functions. So if you do have strange behaviour in any way first switch OFF DSP NR and DSP NB and test again before starting an issue report.
• PIN-diode switching stage causes TX signal distortions. If you see distorted TX signal on some bands / frequencies / power levels mostly PIN-diode switching is the cause. You can test this by removing C78 on RF board temporarily. If distortions disappear PIN-diode switching is the cause. Unluckily we do not know any reliable modification to get this stage working under all circumstances so we recommend to substitute PIN-diode switching by relay switching. Explanation incl. schematics coming soon on modifications page.

NOTE: To preserve short RX to TX switching times (at CW with WPM 28, weight 1: a dot is 44 ms long) there could be an alternative by modifying the PIN diode switch in a way as it is done for VHF and up with a MASW-000936 part. An idea is to take a higher reverse voltage for the PIN diode switch (for example +30V instead of +5V). It appears that there is no simple DC/DC voltage up-converter which would cause no additional interference to HW so this option is still to be explored further.