K3 SSB Output Greater on USB

[Roy Morris-6]

I find the SSB peak output greater on USB than LSB.  This anomaly occurs on all bands and can be as much as approximately 15 to 25 watts peak difference depending on band.  I hope this can be corrected in firmware.  Roy Morris  W4WFB  K3  #323
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[michael stevenson-3]

I also find USB gives a greater peak output than LSB, filter 2.7k. Hope this
can be fixed.
Peak power output still only about 80 watts with CONFIG: TXG VCE set to +3dB
but if this means the output is very clean, I can live with this lower
output power.

Mike G8ALS
----- Original Message -----
From: "Roy Morris" <[hidden email]>
To: <[hidden email]>
Sent: Tuesday, May 06, 2008 1:14 PM
Subject: [Elecraft] K3 SSB Output Greater on USB


I find the SSB peak output greater on USB than LSB.  This anomaly occurs on
all bands and can be as much as approximately 15 to 25 watts peak difference
depending on band.  I hope this can be corrected in firmware.  Roy Morris
W4WFB  K3  #323
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[Jerry Flanders]

Most amps in common use provide a negative-going ALC voltage. And
most rigs in common use are compatible with this. The K3, however,
requires a positive-going voltage.

According to the K3 FAQ at
http://www.elecraft.com/K3/K3FAQ.htm#SignalArchitecture , " Once ALC
is working to our satisfaction, we'll provide simple interfacing
information that will allow the use of negative control voltages
(probably a resistive divider pulled up to a positive supply, or at
most an op-amp circuit)."

The ALC appears to be working OK now. If this is correct, I would
like Elecraft to give me the information to build the interface circuit.

Whether or not someone on this list thinks that ALC is not necessary
or not wise in the average ham station is not important to me at this
time - the engineers at Yaesu do not agree with you concerning their
Quadra amp. They tell me that I must connect ALC for emergency
protection of the finals.

Quoting from my Quadra's manual p4.:
"The ALC cable must be connected between
the transceiver and VL-1000 to
prevent overdrive of the amplifier, and especially
to facilitate the proper operation of the
protection circuitry if sudden antenna system
problems should cause the SWR to rise to dangerous
levels."

Jerry W4UK (Two Quadras, One K3 with another K3 on order.)

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[wayne burdick]

Jerry Flanders wrote:

> Most amps in common use provide a negative-going ALC voltage. And most
> rigs in common use are compatible with this. The K3, however, requires
> a positive-going voltage.
>
> According to the K3 FAQ at
> http://www.elecraft.com/K3/K3FAQ.htm#SignalArchitecture , " Once ALC
> is working to our satisfaction, we'll provide simple interfacing
> information that will allow the use of negative control voltages
> (probably a resistive divider pulled up to a positive supply, or at
> most an op-amp circuit)."

Jerry,

The ALC function is still disabled, but I plan to turn it on and
provide the interface details by the end of this week. Would you like
to test the implementation prior to general release?

73,
Wayne
N6KR

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[DL5OCD]

Hello,

this occurs since i have my K3 #776. It was Rev. 1.78 i think.....

73
Michael

Roy Morris-6 wrote

I find the SSB peak output greater on USB than LSB.  This anomaly occurs on all bands and can be as much as approximately 15 to 25 watts peak difference depending on band.  I hope this can be corrected in firmware.  Roy Morris  W4WFB  K3  #323
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