[Elecraft] Key Click article at EHam

Wed Jan 29 16:45:00 2003

Tom Rauch's (W8JI) article on keying is excellent and well worth
reading. He has done a lot of theoretical and experimental work in
this area and has come up with several mods for Drake and Yaesu
transmitters to reduce keying artifacts  (clicks and other undesired
effects).

Ken, I haven't done much checking on my K2, but I have examined the
r-f output envelope of the keyed CW signal to study the keying
waveform.

The rise and fall times are very short - in the order of one
millisecond - and that normally results in key clicks. However, it
also results in "hard" keying which tends to make the CW signal stand
out in comparison to those with softer keying (longer rise and fall
times). From the shape of the trailing edge transitions, I would
expect to hear some click effect from the "break" of the keying,
perhaps more so than at the "make."

The leading edge makes an abrupt transition from "off" but arrives at
full "on" in a gentle curve. The trailing edge appears to make abrupt
transitions both at the beginning and end. Hence, the expectation of a
harder break than make. More work to do . . .

Maybe this is part of the mojo!   <:}

Thanks for reminding me that I want to look into this further,
especially to look at the spectrum of the keyed signal to judge the
bandwidth, etc.

One positive note is that the K2 evidently does not suffer any of the
"dot shortening" ills of rigs like the Icom IC-756PRO and PRO2 and
others like them. Neither does my older IC-765 which, like the K2, is
NOT an IF DSP radio.

73/72, George
Amateur Radio W5YR -  the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489  IC-765 #2349 IC-756 PRO  #2121 IC-756 PRO2 #3235

----- Original Message -----
From: "Kenneth McGuire" <[email protected]>
To: <[email protected]>
Sent: Tuesday, January 28, 2003 3:26 PM
Subject: [Elecraft] Key Click article at EHam

eHam has an interesting article on Key Clicks...  I posted a response
saying that the K2 was designed to not have this problem, but could
someone with better data follow up?  It seems the perfect place to
show how our little radios stand out in the CW world...

Ken McGuire
KC8LTL