Being the historical person that I am, I believe the concept of
semi-breakin happened with the KWM2/S-line. CW came from an audio
oscillator that modulated the TX in USB [IIRC]. VOX worked, it
apparently thought it was me talking, and picked up, and when I quit
sending, it delayed whatever I had set on the back chassis, and dropped
the carrier. It was the same delay as when I was on SSB. Until it
dropped, all I heard was my own sidetone or nothing.
Absolute true breakin ... hearing between dits and dahs ... probably
only occurred on maritime duplex circuits in those days. I remember in
the very late 50's, still in college, if your receiver would recover
between words, that was close to QSK ... between letters, "You've made
it!"
Nowadays of course, QSK seems to mean you can hear the station between
dits and dahs. While that may be technically true, I don't think it's
operationally realistic. If I'm QSK [and I am all the time on my K3],
if the other guy needs to interrupt me, he sends ... doesn't matter
what. I doubt I hear specifically between dits and dahs at 20WPM [my
imposed max speed in traffic], but he sends a series of dits or dahs,
and I hear those. I don't know if I hear him between dits or dahs, I
just know he's interrupting me.
I enjoyed the duplex maritime operation, I just heard them between
whatever I was sending. Simplex QSK today blanks the RX noise for the
duration of a dit or dah, and I then hear it, an inverted copy of what
I'm sending. It takes some getting-used-to.
73,
Fred K6DGW
- Northern California Contest Club
- CU in the 2013 Cal QSO Party 5-6 Oct 2013
- www.cqp.org
On 12/4/2012 4:28 PM, Edward R Cole wrote:
I suppose this forum is a good place to ask as so many are CW ops.
I am evaluating a pcboard relay for switching RF (Tx/Rx) and need to
know what speed that the relay needs to qualify for semi-breakin. Also,
a precise definition of semi-breakin would be nice.
I get that QSK results in transfer from Tx to Rx after every CW
character. I'm guessing semi-breakin switches when there is a pause in
transmitting. I can evaluate the switching speed of my candidate relays
using a storage scope but need a precise number on how fast they need to
be.
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