ORIGINAL MESSAGE:
On Wed, 5 Sep 2007 16:14:34 +0000, "A.Oskarsson" <tf3ao@simnet.is>
wrote:
>I was wondering what kind of FSK interface would be best for my ICOM 756PROII.
>I have seen the one that Don AA5AU describes on his page, or would it be
>better to use an optocoupler for this (like the one described by IK3QAR)?
>73 Seli TF3AO
------------ REPLY FOLLOWS ------------
Optocouplers are good for reducing hum caused by a voltage potential
difference caused by the computer ground and transceiver ground not
being connected together. To reduce hum to the lowest possible level,
connect the two chassis together with a heavy copper wire, and be sure
to plug both AC plugs into the same outlet, so the ground wires in the
two plugs have essentially zero resistance between them.
Having your computer plugged in at one wall socket and the rig into a
different wall socket is asking for hum trouble.
I am using a basic, non-opto serial cable I built back in the early
'90s and have used on countless computers and transceivers. Still
works like a charm.
Bill W6WRT
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