[CQ-Contest] Optical and galvanic isolation

[Steve Murphy]

Hi Paul,

I don't really see a need for optos unless you've got an unusual situation, for instance: a difference in ground potential between your rigs and the switchbox.  I did use them at one time in a homebrew SO2R controller, but only because I had a bunch and just wanted to do something different, hi.  

IMO, a simple open-collector 2N2222/2N3904 type keying circuit is perfectly adequate for modern rigs that use a positive voltage on the keying line.  

Same with the headphones, an isolation transformer is overkill if you're just doing A/B switching between two rigs.

Others may have differing experiences, but these methods have been 100% reliable for me.  I try to keep things as simple as possible; whenever I try to get too cute, it comes back to bite me in the butt.

73/GL

Steve N8NM