[Elecraft] [KX3] JT65 and JT9 possible TX issues

[Don Wilhelm]

Gary,

You need to increase the audio drive to produce 4 bars solid on the 
"ALC" meter with the 5th bard flickering.
The KX3 "ALC" meter shows the relative audio level in the 1st 4 bars - 
this is not actually ALC activity, but more like a VU meter.
The onset of ALC is indicated by the 5th bar and above.

Do not attempt to control the KX3 power output with the audio input - 
run the audio input full and adjust the desired power level with the 
power knob.  I know that is different from the conventional advice given 
for other transceivers, but the way the KX3 controls power is different 
from the power control mechanism on other amateur transceivers.  If you 
do not drive the KX3 audio fully, the power control circuits will "power 
hunt".

73,
Don W3FPR

On 5/7/2015 1:11 PM, Gary Hawkins wrote:
> I've successfully setup my KX3 with HRD 5.4.28 and WSJT-X, using a 
> Signalink to interface audio to computer (my first attempt at digital 
> operation).
>
> Everything seems to work well on receive, and I can hear and decode a 
> good number of stations in both modes (WSJT-X will do simultaneous 
> decode of both JT65 and JT9 with BW set to 4kHz).
>
> While TX is functioning (running 3W, ALC=0, have not done temp 
> compensation but have VE7FMN heatsink), reception by other parties has 
> been difficult.  Using JT65-HF I've had a couple of incomplete QSOs - 
> the receiving station has been able to decode and respond at least 
> initially.  Using JT9 the one station I contacted reported unable to 
> decode, after trying on several different occasions/times.
>
> So my questions are what are the capabilities of the KX3 in this 
> configuration for these modes, i.e. running at 3W and with heatsink 
> fitted?  Should I expect the KX3 to be able to function in both modes 
> TX without issue, particularly relating to internal heat build-up, 
> freq stability)?  Any thoughts on likely issue - pls ask for more 
> details of setup if required?