K3 single band mic audio anomaly

[K5SM]

As I am (almost exclusively) a cw operator, I had not noticed this until
recently. On 6 meters (and only 6 meters), when I first turn on the K3,
if I am in ssb mode, the audio level (output) seems to be very low.
However, as I continue to speak, it gradually (a few seconds) builds up
to normal output and behaves normally until I turn the radio off. I
suspect this is an audio issue, as I have full output on cw from the
first dit. SSB operation on other bands is normal.  I set the audio
levels and compression using the operator's manual instructions, but
only after the output has built up. Are audio (mic) settings are band
specific? Should I do my setup from a cold start and not after the
output has normalized? I suspect this is operator error of some kind,
but just can't seem to sort it out. Anyone have any ideas?

Bob K5SM
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[Joe Subich, W4TV-4]

 > Are audio (mic) settings are band specific?

No, but the power (gain) calibration is band specific.  You might be
able to eliminate the problem by running the power calibration process
in the K3 Utility (or doing a manual single band calibration on just
six meters).

73,

    ... Joe, W4TV


On 7/18/2011 1:59 PM, Robert Redmon wrote:

> As I am (almost exclusively) a cw operator, I had not noticed this until
> recently. On 6 meters (and only 6 meters), when I first turn on the K3,
> if I am in ssb mode, the audio level (output) seems to be very low.
> However, as I continue to speak, it gradually (a few seconds) builds up
> to normal output and behaves normally until I turn the radio off. I
> suspect this is an audio issue, as I have full output on cw from the
> first dit. SSB operation on other bands is normal.  I set the audio
> levels and compression using the operator's manual instructions, but
> only after the output has built up. Are audio (mic) settings are band
> specific? Should I do my setup from a cold start and not after the
> output has normalized? I suspect this is operator error of some kind,
> but just can't seem to sort it out. Anyone have any ideas?
>
> Bob K5SM
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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[Terry Posey]

Hi Bob -

It is not an operator error problem, and it is not a microphone level or
compression problem.

I have experienced the same problem you are describing with my K3 on 6m.
The cause of the slow ramp-up of SSB audio (RF output) is due to the K3's
internal RF power automatic gain control.  The K3 uses band specific gain
control factors to set the RF amplifier stage gains.  These gain control
factors are calculated and stored during the power calibration process in
the K3 Utility (or by doing a manual single band calibration on just six
meters), as Joe W4TV stated. On 6m, the K3 Utility performs the power gain
calibration at 52.0 MHz and stores the resulting gain control factor for use
across the entire 6m band: 50.0 MHz to 54.0 MHz.  However, if the K3 power
amplifiers or RF band pass filters are not flat (constant gain) across the
band, then the 52.0 MHz RF gain control factor will be incorrect at other
frequencies and you will experience slow AGC ramp-up to the target RF output
level.  A faulty RF band stop filter was the cause of my K3's slow ramp-up
RF output.

If you are unsuccessful in eliminating the problem by running the power
calibration process in the K3 Utility, I recommend you immediately contact
Elecraft support.

73, Terry K4RX


>>>>>>>
As I am (almost exclusively) a cw operator, I had not noticed this until
recently. On 6 meters (and only 6 meters), when I first turn on the K3,
if I am in ssb mode, the audio level (output) seems to be very low.
However, as I continue to speak, it gradually (a few seconds) builds up
to normal output and behaves normally until I turn the radio off. I
suspect this is an audio issue, as I have full output on cw from the
first dit. SSB operation on other bands is normal.  I set the audio
levels and compression using the operator's manual instructions, but
only after the output has built up. Are audio (mic) settings are band
specific? Should I do my setup from a cold start and not after the
output has normalized? I suspect this is operator error of some kind,
but just can't seem to sort it out. Anyone have any ideas?

Bob K5SM

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