[Elecraft] K3 Mechanical Bug Contact Bounce

[Ron D'Eau Claire]

Wow! What a variety of experiences! 

I use two different bugs with my K2 and my K3: a Vibroplex Standard and the
E.F. Johnson version of the Speed-X.

I solved the "scratchy dot" syndrome by cleaning the contacts with DeOxit.
Buffing with paper worked, but only for a short time. A drop of DeOxit
between the contacts for a minute before the excess is wiped off fixes the
problem for months at a time.

The knowledge of the "ancients" said that nominal current flowing through
the contacts actually help keep them clean - as long as it's enough not to
cause arcing. 

Modern rigs do not provide that current. Hence a film of condensed oils/dirt
from the air collects on them raising the resistance when they are closed,
causing the associated keying circuits to behave erratically. 

I wonder if the cap, which would charge up whenever the key is open, is able
to provide sufficient current upon closure to avoid that happening? 

Ron AC7AC

-----Original Message-----
I disagree. I use 3 different bugs with the K3 (GHD, Vibroplex), and have no
such problem - but for years I've tucked a small piece of foam behind the
dot contact spring to eliminate ragged dot syndrome. Also, the bug needs to
be adjusted properly - with an old Simpson 260 across the bug, I  adjust for
a 50% of full scale (Rx100) resistance reading on a string of 8 - 10 dots.

Bob NW8L

On Tue, Sep 16, 2008 at 8:18 AM, Stephen Ellington <n4lq at insightbb.com>
wrote:
> Bugs will not work correctly with the K3 unless a capacitor is 
> installed across the key line. The TenTec Omni VII has the same exact 
> problem. Radio Shack sells a tiny Tantalum capacitor 1uf., which work 
> perfectly. You can actually install it inside an RCA plug or simply 
> slip the capacitor's leads under the screws of your bug. Cleaning the bug
contacts has nothing to do with this. Steve N4LQ