[Elecraft] K3 power drop

[Don Wilhelm]

  Steve,

Assuming you are operating RTTY in AFSK mode rather than FSK, my guess 
is that you are not driving the audio input to the K3 sufficiently.

Use TX TEST and observe the ALC meter.  Bring the audio up until you 
have at least 4 bars on solid and then increase it a bit more until you 
just barely see the 5th bar illuminate.

Contrary to "classic" instructions, that say you should not have any ALC 
indication, the K3 "ALC" meter is both a "VU" meter and an "ALC" meter.  
The onset of ALC does not occur until the 5th bar - below that it is an 
indicator of audio drive.

The most common result of having the audio into the K3 too low is just 
as you have stated - it takes a long time for the K3 power output to 
come up to the requested level.

Bottom line, ignore the "classic" advice, and drive the audio as 
instructed in the K3 manual, and adjust the power output with the K3 
power control knob.  Attempts to control the power output by adjusting 
the audio drive level will result in the "Power Creep" that you have 
observed.

The way the K3 controls power output is different than that if most 
other transceivers.  The K3 actually monitors the power output and 
attempts to control the transmit gain accordingly.  Other transceivers 
use their ALC mechanism to control the power output - the K3 does not 
(for those listening, the K2 is similar).

73,
Don W3FPR

On 2/12/2011 11:41 PM, aa4v at bellsouth.net wrote:
> I noticed today when starting to transmit on RTTY in the WPX test, although the power out from the K3 was set on 60 W, the rig only put out about 30 W for the first several transmissions then the output gradually rose to 60 W as selected. The antenna SWR is 1.5.
> Any ideas? S/n is 855 But has bEen updated to current specs.    Steve KH6/AA4V
> Sent from my Verizon Wireless BlackBerry
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