[Elecraft] K3 - qsk keying loop

[Eric Swartz - WA6HHQ Elecraft]

Hi Barry,

There is a lot of confusion and mis-information about the need for CW 
keying loop feedback from the amplifier to the rig in the amateur 
community. While certainly it was necessary on some older rig and amp 
combinations, it is not necessary with a properly designed rig today 
that has sequenced amplifier key-out to RF output. As an example, I run 
both my K2 and K3 in full break-in with my Alpha 87a amplifier with no 
timing problems or reduction in break-in performance.  A large number of 
our customers run full break-in with our rigs in this manner using a 
wide range of full break-in amplifiers. There is no degradation of rig 
break-in performance when using the K2 or K3 in this manner. A large 
number of our K3 Field Testers are break-in CW ops with amplifiers and 
none have had any issues with running our rigs with their amps.

I think that since some are used to using a keying feedback loop on 
other rigs and amps that it is necessary on all. I guess I disagree :-) 
. RF sensing in the AMP is absolutely not needed with proper key-out to 
RF sequencing from the rig. And excessive delays are -not- needed.

But, if it can be shown that we actually can increase K3 break-in 
performance with an amp by doing something like this, we'll certainly 
look at doing it.

73, Eric   WA6HHQ

_..._

Barry N1EU wrote:
> K7GT obviously has the same concerns.  Over the past decade I've used
> a slew of Ten-Tec and Yaesu xcvrs interfaced to Ten-Tec, Alpha, and
> Acom amplifiers via plug 'n play keying loops with uniformly excellent
> performance.
>
> The lack of QRO QSK with the K3 may be a big issue with some
> prospective K3 contesters.
>
> 73,
> Barry N1EU
>
>
>   
>> Don, in the email below, says that the time delay in the K3 will accommodate
>>     
> a QSK amp. That is only partially true. The problem is in setting it
> up. I could,
> of course, put in a LONG delay but then QSK is gone. If I crank the delay down,
> at some point I am relying on the RF sensing circuitry in my QSK amps to hold
> the relays closed until RF is really gone from the input. That may work but I
> would really prefer the sure-fire solution of a keying loop. This allows a QSK
> amp to be set up optimally by just plugging in and does not require a scope
> and a bunch of fuss. The QSK of my Tentec transceivers coupled with
> either the Titan or Hercules II QSK amps is plenty fast for me as I
> never go above 50 wpm anyway.
>
>   
>>