[Elecraft] KX3: ALC on digital issue

[David Anderson]

In reply to Jim et al

Using Digital modes like WSJT JT65b and FSK441 here with my KX3 and let me explain what I see and how I interpret it. I am curious to know if you see something different.

Using Mode DATA A (Important because it turns off any transmit equalisation and compassion you may have set on SSB mode).

Initially turn Power down to 0  while setting up. To prevent any accidental QRM, or use a dummy load.

While sending data from the digital software, adjust mic gain and or level from sound card interface to get just over 4 bars on the "ALC" bargraph. This is not really ALC but rather audio level that the bargraph is displaying. It is not until 5 bars that ALC is actually produced, so try to keep it just below 5 bars. The transmit audio level is now set correctly and should need to be touched again.

Still while transmitting data you can now adjust POWER with the control and you will not see any change in the ALC level, however the power that you have set will be shown in numerals on the display. If you have an external RF power meter you can confirm that indeed the power level is adjusted in realtime as you vary the POWER control while transmitting in DATA A. [It is this part that you seem to have a different result? Are you saying the POWER control does not adjust the power out while transmitting ? - It most certainly does on my KX3]

It is important to not try and adjust power by varying the audio level from the sound card interface or the mic gain control, as that will lead to an unstable power level. 

Ignore any online instructions that tell you to adjust power and ALC by audio level adjustment, they refer to non Elecraft radios which work in an entirely different manner.


73 from David GM4JJJ

> On 5 Feb 2016, at 16:37, Thorpe, Jeffrey <jthorpe at liberty.edu> wrote:
> 
> I actually noticed the same thing too...the only difference was that I was transmitting Contestia 4/250.
> 
> Jeff - kg7hdz
> 
>> On Feb 5, 2016, at 08:36, Jim Rodenkirch <rodenkirch_llc at msn.com> wrote:
>> 
>> Hey, guess what I found out.....I saw the same thing while operating JT9/65.
>> 
>> BUT, every time I rotated the pwr control knob, the ALC was exactly where I
>> had adjusted it to, SOOOOOOOOOOOOOOOOO, I experimented a little and varied
>> the pwr out prior to transmitting.....guess what???? The power level bars
>> indicate exactly where I set the pwr at....looks to me like the KX3 will
>> display then set pwr when you start transmitting in JY9/65 and, if you touch
>> the pwr knob after you start transmitting the KX3 display your ALC
>> setting.....just sayin'!!!
>> 
>> I don't do any other digital/rtty mode so don't know how the KX3 works wid
>> 'dem!!!
>> 
>> 72 de Jim R. K9JWV 
>> 
>> 
>> 
>> --
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