There's been some recent discussion of how to properly set up the K3 in
SSB modes. I meant to respond sooner but was out of town for several
days.
MIC GAIN SETTING: Adjust MIC gain for an ALC meter peak at around 5 to
7 bars during normal speech (rev. D owner's manual, page 28). This
applies even to TX TEST mode, meaning you can set it off-air. This
indication does not mean that you're "hitting the ALC really hard."
When you get to around 5 bars, you'll be "tickling" the DSP's ALC. More
on this below.
ALC METERING: The K3's ALC meter is a bar graph, not an analog meter,
and we felt that 5 bars would provide the right granularity at the
target ALC level. The 5th bar of the ALC scale is heavier than the
others, serving as a reminder of the this level.
ALC DESIGN GOAL: The K3 was designed to minimize transmit splatter and
other effects that plague some rigs. To achieve this, we apply all ALC
*before* the crystal filter, and minimize the application of ALC in
general. The levels have been carefully calibrated to that 5-to-7-bar
level mentioned above. The result is that the crystal and DSP filters
remove the types of artifacts that in many other rigs end up as
transmitted wideband noise or clicks. I believe this is why we continue
to hear excellent reports from K3 users regarding their on-the-air SSB
signals. (We've also heard, from some experts in the subject, that the
K3's compression is among the most effective they've ever measured.)
PER-BAND POWER CONTROL: With some vocalizations, speech energy may
build up within a narrow crystal filter to produce a slight peaking
effect. Because of this, the user must set the K3's power output level
such that it peaks at or below the safe level for any external
amplifier under all speech conditions. To facilitate this, you can use
per-band power control (refer to the PWR SET configuration menu entry).
We have many customers using this method. It compensates for per-band
gain variation in the external amp or the K3 itself, again reducing the
need for ALC. For example, all crystal filters have a small amount of
ripple (typ. +/- 0.5 to 1.0 dB) that can result in a slight difference
in average power output between LSB and USB with some voice
characteristics. But since you typically use only one of the two
sidebands on a given ham band, per-band power control can conveniently
compensate for small variations.
TX GAIN COMPENSATION FOR VOICE MODES (TXG VCE): If you find that your
speech peaks are routinely above the desired level (i.e., higher than
CW power output using TUNE), you can adjust the TXG VCE menu parameter
downward in 0.5 dB steps. Conversely, if your normal speech
characteristics result in lower power output compared to CW TUNE, you
can increase TXG VCE above the 0.0 dB level.
I'll be happy to answer any further questions. Our goal is to improve
the manual to make the above as clear as possible.
73,
Wayne
N6KR
* * *
OK?
W
---
http://www.elecraft.com
_______________________________________________
Elecraft mailing list
Post to: Elecraft@mailman.qth.net
You must be a subscriber to post to the list.
Subscriber Info (Addr. Change, sub, unsub etc.):
http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/subscribers.htm
Elecraft web page: http://www.elecraft.com
