[Elecraft] KX3-MIC & COMP Setting / Metering

Discussion:

Jim - W6VAR

2012-09-12 14:50:15 UTC

I'm curious what MIC GAIN and COMPRESSION settings everyone are using with
the MH3 microphone. ALC metering is quite spotty after getting an initial
peak and compression metering doesn't show much either. Gary tells my to
just adjust for power out, but this is complicated when on battery, because
power is folded back and the metering automatically switches back to
ALC/CMP.

I have made one SSB contact with a MIC setting of 12, and received favorable
audio.

Compression seems to kick on hard listening with the monitor, so a left the
setting at only one.

Hopefully, future firmware will fix the ALC/COMP metering to be smoother and
more responsive like the K3.

Jim

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Don Wilhelm

2012-09-12 16:36:20 UTC

Permalink

Jim,

Rather than getting someone else's settings, why not adjust yours the
"way it should be"
Work into a dummy load or turn the power to zero - then
First set compression to zero, then adjust the mic gain to produce 5 to
7 bars on the ALC meter. You mic gain may be 25 or higher, but the
number of ALC bars is the most important factor.

Then turn up compression to suit your operating desires - listen on the
monitor until it sounds right.

73,
Don W3FPR

Post by Jim - W6VAR
I'm curious what MIC GAIN and COMPRESSION settings everyone are using with
the MH3 microphone. ALC metering is quite spotty after getting an initial
peak and compression metering doesn't show much either. Gary tells my to
just adjust for power out, but this is complicated when on battery, because
power is folded back and the metering automatically switches back to
ALC/CMP.
I have made one SSB contact with a MIC setting of 12, and received favorable
audio.
Compression seems to kick on hard listening with the monitor, so a left the
setting at only one.
Hopefully, future firmware will fix the ALC/COMP metering to be smoother and
more responsive like the K3.
Jim
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James Kohnke (W6VAR)

2012-09-12 17:00:10 UTC

Permalink

Understood, but the metering isn't working right. Protocal described was from Gary at Elecraft.

Sent from my iPhone

Jim,
Rather than getting someone else's settings, why not adjust yours the "way it should be"
Work into a dummy load or turn the power to zero - then
First set compression to zero, then adjust the mic gain to produce 5 to 7 bars on the ALC meter. You mic gain may be 25 or higher, but the number of ALC bars is the most important factor.
Then turn up compression to suit your operating desires - listen on the monitor until it sounds right.
73,
Don W3FPR

Don Wilhelm

2012-09-12 17:40:45 UTC

Permalink

Jim,

OK, but I did not think there was a problem with the metering - the KX3
manual says to adjust for 5 bars, but the K3 says to go up to 7 bars, so
the 5 to 7 bar comment was in error.

I have 1.12 firmware in my KX1 Yes, it is difficult to drive the ALC
above 5, but I suggest driving it up to 5 bars and then go just a bit
higher - then bring up compression to your taste. My MH3 runs about 35
on the mic gain and 15 on compression.
OTOH, I have a Yamaha CM500 running with an adapter to connect only the
tip instead of the stock plug that connects the tip and ring together -
that runs well with the mic gain set to 20 and compression to 15 - that
is one hot microphone element.

73,
Don W3FPR

Post by James Kohnke (W6VAR)
Understood, but the metering isn't working right. Protocal described was from Gary at Elecraft.

Oscar Staudt

2012-09-12 19:15:49 UTC

Permalink

Well, maybe some KX3s react a bit differently. I, also, noticed the
phenomenon Jim described. With the KX3, and either the MH3 or my Yamaha
CM500 I couldn't seem to talk at a volume to get 5 bars ALC (or 4, or 3) by
raising and lowing my voice volume level even with mic gain up near 40 (and
comp set to 0). If I talked loud, I'd show 6 or 7 bars, if I decrease my
voice volume a bit, I'd get no bars.

As Jim described, this is very unlike my K3, where the ALC level (shown by
number of bars) seems very linear, and tracks with my voice volume. With
the KX3, it's more like an "all or nothing" meter reading. Perhaps there's
some other setting not right. I still have the original firmware as
shipped (serial 1130).

At least on my KX3, adjusting the mic gain does not feel at all like doing
the same thing on the K3

I might also note a few other factors:
1. I was able to turn the mic level way down after adjusting TX EQ
bringing up the mid and high frequencies by 12db (and two lower frequency
bands down by 10db). This made everything a bit better.
2. When listening to my voice with mon on, the voice volume/level DOES
seem to be linear and follow the volume of my speech - it's only the ALC
metering that appears not so linear.
3. Using the same CM 500 on my K3 and my KX3, with about the same TX EQ
on both, people have commented the KX3 sounds like it has a lot more bass.
This may not be related...

Oscar, WB5GCX

Post by Don Wilhelm
Jim,
Rather than getting someone else's settings, why not adjust yours the
"way it should be"
Work into a dummy load or turn the power to zero - then.......

Jim - W6VAR

2012-09-13 13:40:29 UTC

Permalink

Well,

Mostly because Gary at Elecraft told me he monitors power output since the
ALC meter isn't driving right and that is what he recommends. That is
difficult in the field on batteries because the target power is variable
based on voltage. Also, the meter defaults to ALC when adjusting mic gain
making it hard to see power while adjusting since this can't be overriden.

I'm also concerned about having a dirty, overmodulated signal, so I'm
staying conservative. As near as I can tell, I may be okay with a setting as
low as 10-12, and 1 on compression but others are saying they are driving
with as much gain as 40+ and significanltly higher compression.

This seems to be a pretty broad range for everyone with identical equipment
to be properly adjusted (understanding minor differences may occur with
different voice characteristics)

I haven't had a chance to coordinate a contact with a local friend and I
have difficulty listening to my own voice in a second receiver.

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Ignacy

2012-09-13 14:52:11 UTC

Permalink

I use a small electret mike form an old computer. Mic gain of 6 causes ALC
activity just below full scale. Reports indicated that COMP to the max (30)
produced punchy and undistorted signal. When listening on K3, varying mic
gain from 4 to 10 caused very little difference in speech quality.

IM in KX3 strongly depends on the combination of power and voltage. See a
document in file section on yahoo KX3 site. Too much power at low voltage
can cause IMD of -20db. The effect of mic gain and compression on IMD is
much lower than that of voltage. Confirmed on P3.

KX3 seems to be very sensitive to low voltage as far as efficiency is
concerned. For example, at 12V the radio draws 2.2A and produces 10W.
About 38% efficiency and 16W dissipation. At 8V (NiMH under load), the radio
produces 2.5W and draws 1.8A, for 17% efficiency and 12 W dissipation.
Voltage and amp readings from KX3.

Setting power to 5W at 12V, the radio draws 1.1A, for 38% efficiency and 8 W
dissipation.

Not all of it is bad as many other radios stop working < 11V.

Ignacy, NO9E

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