[Elecraft] ALC indication on K2

[Rich McCabe]

Ron,

Thanks for the reponse. See comments below



> The first question to answer is whether the K2 makes full RF output in CW
> mode (10 watts if a K2 or 100 watts for a K2/100) into a suitable dummy
> load. If not, then you need to  troubleshoot the transmitter signal path
to
> find out why it's low.

Yes, seems to do OK,  Little over 100 watts on some bands but a few as low
as 85 watts.

> If the CW power reaches spec then take a  close look at how the ALC
behaves
> as you reduce the POWER setting.
>
> First, be sure you have SSBA set to 2 or 3. SSBA 1 attenuates the mic
input
> about 10 dB.

Have tried SSBA 2 and 3 both. Not using 1.
>
> Next, see how close to full output you are. If you start to see ALC on 160
> as you drop the POWER control slightly below maximum (say, down to 9 watts
> instead of 10 for a K2 or 90 instead of 100 watts for a K2/100) then you
> have ALMOST all the gain you need. It's probably too close to care about.
> But if you have to drop the POWER level too far, then you probably need a
> little more audio into the mic jack. (The K2 RF indication on the
bar-graph
> is a "peak reading" output meter, so you can see directly how much power
you
> are getting by watching it too).

Well on the 100 watt unit I have to get down to around 40 watts before I
start to get 1 bar of ALC on the 100 amp. On the K2 alone have to get down
to around 1 watt. Both are occasional flickers with normal voice. As I
mentioned 80 and 40 are higher. They get a couple bars at full output. The
other bands are about 1 bar at full output with the exception of 10 meters
which I have to drop to about 85 or 90 watts to pickup a bar.

>
> Increasing the audio level from your microphone is the usual way to
increase
> the RF signal path by getting more out of the balanced modulator. That
works
> FB as long as you don't use so much extra amplification in the mic that
you
> over-drive the audio or balanced modulator.
>
> One easy mod to get more audio without changing mics or adding an external
> mic pre-amplifier is to change R14 on the SSB board. The "stock" value is
> 1k. Raising it to about 6K ohms will provide substantial additional gain
> with most mics.

I might have to try the resistor swap and see how it works. Looks like 160
is the biggest culprit. I was just worried I was not getting the output I
need. I am having a little trouble getting the VOX right. Have to "talk up a
little" to get it to stay in and then sometimes even the slightest breath
can trip it.

Thanks again,

73,

Rich
kd0zv