[Elecraft] K3 TX delay

[W5UXH]

According to the manual TX DLY description:

"...sets the time from KEY OUT jack .. to first RF in 1-ms steps"

I agree with your measurement of 9 msecs from KEY IN to RF.  Approximately 5
msecs is lost in the K3 between KEY IN going low and KEY OUT going low.  At
least in QRQ mode.  I have not spent time looking at non-QRQ mode since QRQ
is the only mode I use.

I normally use the KEY OUT jack to control the qsk boxes for amps and it is
this delay that is important to me.  I have implemented my own KEY OUT line
that goes low coincident with KEY IN but goes high again approximately
coincident with KEY OUT.  This is needed with my miniature relay qsk boxes
(a la AD5X) since the ~4 msecs setup time is too close for comfort to the
relay switching times.  It does not work with my PIN qsk boxes because the
diodes switch before the K3 RX is muted, producing nasty clicks!  I normally
use diode qsk, so the KEY OUT line is fine for that.

Chuck, W5UXH


P.B. Christensen wrote:
> 
>> I am under the impression that the TX DLY setting of "8 msecs" does not
>> actually produce an 8 msec delay between KEY OUT going low and start of 
>> RF.
> 
> At the default 8 ms setting of TX DLY, I measure ~ 9 ms of delay in QRQ
> mode 
> between the K3's key *input* line and RF.  So, I agree that the 8ms figure 
> is not associated with the time measured from the K3's amp key line to the 
> onset of RF. At least, that's the way it measures here.
> 
> In non-QRQ CW with TX DLY still at 8ms, I measure ~ 16 ms between key 
> closure and RF.
> 
> Paul, W9AC 
> 

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