[Dx4win] CW Using DX4WIN

[Larry Benko]

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!
> 
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