[Elecraft] KIO2 cable question

[Don Wilhelm]

Vic,

As a first suggestion - run the pin 1 shield connection through the
switchbox, but do not ground the shield AT the switchbox chassis - you can
bypass it with a capacitor.  Do ground the case of the switchbox to your
station ground.  That will give you the continuous 'ground' (actually
common) that you need while preventing ground loops.

This is a case where what we usually refer to as 'ground' is really a signal
path - In the 'old days' I worked some with large computer controllers and
associated terminals - the same rule applied -- connect the cable shield to
round at the source device and nowhere else in the system (but at all other
places consider it as a signal wire to be connected).  Be careful that the
devices you connect are constructed so that the isolated common connection
is feasible - many will connect the shield to their own ground inside the
box.  If that is the case, some rework of that box may be in order.

73,
Don W3FPR

----- Original Message -----

> The manual says that the cable from the KIO2 to the serial port should
have the
> ground braid connected only at the rig end.  I presume that this is to
avoid a
> ground loop that could result in RF pickup.
>
> I am intending to connect my KIO2 to a switchbox so that I can connect
either
> the rig or a packet TNC to the single serial port on my laptop.  If I
don't
> connect the ground at the switchbox, then the box itself and the cable to
the
> computer will be floating with respect to the rig and the computer.
....snip