Frank, An opto-isolator is an excellent galvanic isolator and a very good 50/60Hz and through audio frequencies isolator but NOT a very good RF isolator. DIP type opto-isolators have ~1pF of capacitance which equates to 5600 ohms on 10m. Yes there are RF type opto-isolators which are LEDs and a 1 inch long light pipe connected to a phototransistor but these are mainly used in the medical industry and are expensive. Commmon mode chokes can actually give more isolation in the upper HF freq. range than opto-isolators. Just my $.02.
73, Larry, W0QE Franki - ON5ZO wrote: > > OK, this is Guy's ON4AOI way of doing it: > > http://users.skynet.be/ON4AOI/keyer.shtml > > He makes a galvanic separation between PC and TRX by means of an > optocoupler. > This is a smart idea that might help to cure some problems with > RFI and noise. > The schematics are also easier to understand than my text > description, hi! > > I personally have NEVER had any problems with the simple circuit, > nor have most of the people I know. But: it definately does not > hurt to make a galvanic separation. Thanks for the hint Guy! > > 73, Franki ON5ZO > > PS: browse ON4AOI's page http://users.skynet.be/ON4AOI/ for > much more usefull stuff for DX4WIN users! > > _______________________________________________ > Dx4win mailing list > [email protected] > http://mailman.qth.net/mailman/listinfo/dx4win
