[Elecraft] CW rise time setting

[Bob Wilson, N6TV]

On Mon, Jun 8, 2020 at 12:31 PM E.H. Russell <ehr at qrv.com> wrote:

> I suppose shaping of the curve corners removes harmonics introduced by the
> abrupt transitions, allowing an accelerated ramp inbetween. But does this
> really reduce the total rise time to 2.5ms? It seems that the softening
> process must take some time. Wish I had a K3 here to scope against other
> radios. Anything published out there?
>

Ed,

Per your request, I am publishing this scope screen capture which plots the
CW rise time in my K3 with the KSYN3A synthesizer upgrade.  It's about 4 ms
from 0 RF to full RF (2 ms per horizontal division):

https://www.kkn.net/~n6tv/N6TV_K3_Ser_1494_FW_05.64_TX_DLY_8_CW_QRQ_OFF.png


The vertical markers are there to illustrate that *CONFIG:TX DLY nor 008*
provides only about *6 ms* of RF delay after "KEY OUT" goes to ground, not
8 ms, and there is jitter in that delay as well (not shown).  If CW QRQ
mode is enabled, the delay drops to about 4.6 ms and the TX DLY setting is
completely ignored.

This was discussed here two years ago.  See this post for suggestions on
how to avoid hot-switching a non-Elecraft amplifier driven by a K3 or K3S:

http://elecraft.365791.n2.nabble.com/Default-K3-transmit-delay-may-be-too-short-for-slow-QRO-amplifiers-td7641779.html


73,
Bob, N6TV