[Elecraft] K2 Auto-Detect Mode

Tue Aug 5 14:22:01 2003

Mike,
I cannot imagine that your diodes will make much difference - unless one of
them has a veeery slooow switching response (= bad diode), or is not pulling
the keying lines to an adequately low level.

I do know that the firmware controls the detection, but I don't know if it
looks at both lines at once or looks at them serially (senses one and then
the other).  If it looks at the lines in parallel, there should be no
software timing problems, but if the sensing is done serially (which is more
likely), there will always be a small but finite time between scanning one
line and scanning the other.  If you hit the key inside that small window of
time, there is a probability for an error.  It is likely that is what is
happening for you.  It should not happen often, but there is a finite chance
that it will - as I started out, a slow diode would make it worse.  It would
be good to match the 2 diodes in the external circuit for switching times
over the 5 volt to ground transition (the only the fall time is relevant
here).

73,
Don W3FPR

----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Tuesday, August 05, 2003 11:37 AM
Subject: [Elecraft] K2 Auto-Detect Mode

| To All:
|
| I'm using the K2 Auto-Detect Mode as described in the K2 Manual with a
paddle and my Vibroplex bug with the appropriate diodes. I'm able to
activate the Auto-Detect mode and bypass the keyer when I use the bug but it
frequently reverts back to the keyer while I'm still sending with the bug. I
get an erratic iambic pattern as if the detection circuit no longer sees a
simultaneous pulling down of the dot and dash lines. I'm using 1N914 diodes,
perhaps I should use 1N5817 or 1N4148 diodes instead? Any suggestions?
|
| Thanks in Advance,
|
| Mike N2JZ
| K2/100 S/N 1651
|
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