> On all 3 units series of dots were sent using external keyer with 50% > weight. While on the monitor output the weight remained to be 50% the RF > output showed shortening of dots (and therefore lengthening of spaces) by > 7 > or 8 msec. This effect does not depend on WPM speed and therefore less > pronounced at slower speeds.
The effect of so-called "dit shortening" becomes more noticeable at higher keying speeds since the amount of rise-time truncation remains fixed for all keyed elements, regardless of keying speed. Igor, were you using PTT CW keying? PTT CW from a contest card results in perfect timing by the K3. In that mode, RF is generated only 3 ms after external key closure and RF keyed element length exactly matches the dry contact closure time. If you were using an external keyer without PTT activation, then you may want to experiment with the NEW and OLD QSK settings. The NEW QSK mode appears to truncate keyed elements to a greater degree than the OLD QSK mode. I see no timing differences between full QSK and Semi-QSK. In OLD QSK, my K3 truncates keyed elements by only 3 ms. That amount is made up by adding 3 ms of compensation with a microHam keyer. With the K3's TX DLY set for the default 8 ms and QSK set for OLD, the total CW delay time from external key closure to the start of the RF envelope is 15 ms. The NEW QSK setting adds further delay of ~ 4 ms for a total delay of 19 ms. However, the added delay is not made up at the end of the envelope and the NEW setting will start sounding choppy sooner than the OLD setting. By the way, the TX DLY setting is meant to control the timing of an external amplifier from the KEY OUT jack until first RF appears in 1 ms steps. But, others have found (myself included), that TX DLY also has an effect on the keyed element duration, particularly the first dit or dah. Paul, W9AC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
