[CQ-Contest] Optical and galvanic isolation

[VA3NR]

Hi Paul,
- I've built keyers with optoisolators and also just with FETs and never had a problem with either method.

- Regarding audio transformers: I built my original so2r headphone switch without one and had constant buzz in audio from one of the rigs.  I added one transformer (on the audio from the left rig) to allow isolating the grounds between rigs and it silenced the buzz.  I used a 1:1 audio transfromer from local electronics store with no mfr. or part number markings.

GL,
Chris VA3NR.