[Elecraft] Scope Pic - K2 Keying Envelope

[Steven Gibbs]

WD1V has posted a fine image of the K2 keying envelope.

The K2 is good on the leading edge (rise), but less
than perfect on the trailing edge (fall) when there is
an abrupt transition when the power is still high.
For minimum bandwith (= minimum key clicks) the
trailing edge should mirror the leading edge (I seem
to remember that a cosine squared waveform function
needs the minimum bandwidth).

I'd be interested to hear about a shaping circuit
which might improve the K2's trailing edge slightly.

The clicky transmissions heard on the bands from some
other rigs aren't all caused by poor envelopes - poor
design means that often the rise in rf output starts
while the PLL is still pulling in to the transmit
frequency, giving an apparent click at the leading edge.
Similarly, a click at the trailing edge could be caused
by the PLL starting its journey to the frequency needed
at receive before the rf envelope has completely decayed.
Clicks caused by PLL timing problems can typically be
heard either low OR high of a transmission.  Clicks
caused by poor envelopes can be heard both low AND high.

These factors must have been properly considered by our
Elecraft design team.

73, Steve, GU3MBS
========
At 09:58 04/02/03 -0500, John Seney wrote:
>Everyone knows K2 rigs hear great and sound great. It should come as no
>surprise that on scope screens, K2s also look great!
>
>Here is a link to a really gorgeous K2 Keying Envelope
>http://www.qsl.net/wd1v/LECROY.JPEG
>72/73
>John Seney, WD1V [FN42]