[Elecraft] K2 Key Clicks

[Len Koppl]

I think that there are some pitfalls when checking for key clicks using
another receiver.  Keying artifacts can be introduced by the receiver
itself, especially if the noise blanker is on.  I couldn't hear any in mine
using a TS-440 and now again using a TS-2000.  So I hooked my Tektronix 2213
(60MHz bandwidth) scope directly to the dummy load, set the internal keyer
to 50 wpm, and observed a string of dots.  I got a picture perfect keying
wave shape.  Looks just like the ARRL handbook.  The rise and fall times
look to be around 1.5 or 2 ms.  While this would not be described as 'soft'
keying, it is not unusually hard either.  As I have the barefoot K2 and
generally run it at 5 W, I doubt that I will strive to change the keying
characteristics.

Incidentally, I looked at my TS-2000, set for a 5 ms rise time. Beginning
code elements (especially at slower speeds) exhibit a small spike at the
beginning of the waveform that the K2 does not.  While the keying is overall
a bit softer than the K2, those beginning elements are a bit harsh.  (Not
terrible, mind you, but since we are picking nits...)

A proposed method for checking keying characteristics is to select a narrow
filter, then adjust the receiver so that the keyed signal is just outside
the passband.  A distinct clicking or thumping can be heard, but does this
indicate transmitted clicks, or is it just the receiver passing along what
little signal is left in the passband?  Maybe an engineering type can answer
that one.

73,
Len, KD�RC