[Elecraft] K2 - QSK

[Vic Rosenthal]

N2TK wrote:
> Well Ron, I would not consider the K2 to have great QSK. Even my TS950SDX
> doesn't have great QSK. It has very good QSK.

I hesitate to get into the middle of this, but here goes.  If your TS950 
is like my TS850, it has extremely fast QSK.  If you test it on a quiet 
band, you will say "wow, that's great, much faster than the K2".  But 
try it in a contest -- you hear really annoying clicks and pops which, 
in my case, negate the advantage of fast QSK.

The reason is that at least in my 850, the t/r switching happens faster 
than the various PLL's can lock.  So if there is activity nearby, you 
will hear it as the PLL's sweep by.  The K2 is designed to wait until 
everything settles down before switching, which is why it is a bit 
slower and a whole lot cleaner to listen to.  Although the QSK can 
perhaps be sped up a bit by various mods, I doubt that it will ever be 
possible to hear between the dits at 35 wpm, unless you don't mind 
hearing the junk.

In 1967, before PLLs were common I had a Drake R4B rx which had a very 
smooth muting circuit.  My tx was a Hallicrafters HA5 hetrodyne VFO 
driving a DX60, driving a homebrew 813 final, protected by a 6Y6 clamp 
in series with a VR150 to give full cutoff.  The final had a t/r switch 
built into it.  This setup produced absolutely perfect QSK.  But then I 
couldn't easily take it camping with me!

Vic K2VCO