[Elecraft] OT: definition of semi-breakin

[Fred Jensen]

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.