[Elecraft] Begali and K2

[Vic K2VCO]

Rich McCabe wrote:
> 
> I just bought a new Begali Signature to go with my K2/100. I was 
> thinking about buying a MicroHam/K1EL USB CW keyer to work with my Pro 
> III so I can run mode B.
> 
> I just ran into this article about a debouncer and the Begali keys. 
> http://www.microham-usa.com/Products/Begali.html
> 
> This seems pretty wild to me, but thought I would toss it out the the CW 
> Pros !  It seems the problem is related to PIC based keyers. Does this 
> apply to the K2 and what do you think about the whole theory?

To a smaller extent, yes it does.  Here's an edited excerpt from a 
review of the Magnetic Pro (very similar to the Signature) that I wrote 
for eHam:

The contact alloy behaves almost like a semiconductor, maintaining a 
constant forward voltage drop over a range of current. Measuring the 
contact resistance with an ohmmeter gives 'funny' readings; it's more 
interesting if your meter has a diode voltage drop range, such as my 
Fluke 79.

Anyway, the result of this is that the key does not work properly with 
keyers like Winkey, which use a single PIC input and voltage divider to 
distinguish dots and dashes. Microham has actually developed an 
interface to solve this problem. More broadly, however, the contact 
resistance behavior causes intermittent problems with other keyers that 
do use separate PIC inputs, such as the Logikey K3 and the internal 
keyers in my Elecraft K2 and TS850s. This problem can be described as an 
intermittent 'misfire', in which there is a delay before dot or dash 
generation starts after the contacts are closed.  I believe that the 
delay is caused by the time constant of the bypass capacitors and the 
variable contact resistance.

The Microham device is reported to help with Winkey, but does not help 
with the Logikey K3 (I tried it).  The delay seems to appear more 
frequently the more heavily you use the paddle, which I suspect has to 
do with the thickness of an oxide layer that develops on the contacts. 
If you let it sit for a while, the frequency of the problem decreases.

The Begali keys can be ordered with gold contacts, which I recommend. 
It's possible to order replacement parts, but since the contacts are 
part of the movable arms, the cost of the replacement kit for my key was 
$78.  I bit the bullet and ordered the kit; hopefully it will solve the 
problem.  In the meantime, I'm using my old Bencher.

Since you already have the key, I suggest that you try it and see how it 
works.  Some people don't report a problem, in my opinion because they 
don't beat on it enough.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco