[Elecraft] K rig's longevity?

[David Woolley]

N2EY at aol.com wrote:
> It's documented, just not publicly. That could always change.

There's no guarantee of any more than poorly commented source code and 
that is true of any actively maintained software, whether it comes from 
Elecraft or someone else.  (It has been said that Microsoft wrote 
Wordpad because they lost the source code for Write, so using the binary 
is not enough.)
> 
> I didn't know they had a limited life - how many operations? What is the 
> failure mode?

All electromechanical components have limited lives.  Typical specified 
electrical lives for relays are 100,000 operations, with rather longer 
mechanical ones.  This is why use of the KIO2 to scan across bands is 
discouraged.

The manufacturers don't specify what constitutes a failure, but an 
electrical one is likely to be parametric, i.e. excessive contact 
resistance, or bounce, and a mechanical one might be sluggish 
changeover, fatigue failure, or, maybe they would count contact welding.

Keeping the switched voltages and currents low, and avoiding inductive 
loads on the contacts may improve the electrical life, as will 
tolerating higher final contact resistances.

(Note these are lifetimes and represent wearout failures.  Components 
may also have random failures resulting in mean time between failure 
figures, which can actually (e.g. hard disks) exceed the wearout lifetime.)
-- 
David Woolley
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