[Elecraft] K3--Too much ALC creates energy on opposite sideband?

[Wes]

What has any of that to do with opposite sideband rejection?

Wes  N7WS

BTW, The HPA kicks in at 12 W.

On 8/28/2019 12:55 PM, Jim Brown wrote:
> Numerical readouts for Mic Gain and Comp are pretty meaningless, because the 
> output of good mics varies widely from one model to another, how close the mic 
> is to the mouth, how loud we talk. The right way to set (and understand) these 
> controls is to look at indicated ALC and CMP on the bar graph display while 
> transmitting. Both adjustments should be made AFTER setting TXEQ. I have long 
> advocated 10 dB of indicated CMP on voice peaks.
>
> It is well known that IMD in the K3 and K3S increases when operating from low 
> DC supply voltage. It also increases when the output stage is operating near 
> its limit, and when the antenna is not well matched to the output stage. If 
> the 100W amp is present, it does not engage until output power is set above 
> about 15W, so IMD is also higher when running 12-15W. The increased IMD of the 
> 100W state can be clearly seen in this set of data.  DC voltage was in the 
> range of 12.5V for these measurements. 
> http://k9yc.com/P3_Spectrum_Measurements.pdf
>
> Pink noise is widely used by audio professionals because its spectral 
> distribution more closely corresponds to music and speech than does white 
> noise. For that reason, pink noise is the best test signal for the evaluation 
> of speech processing systems (like CMP and peak limiting).
>
> 73, Jim K9YC
>
> 8/28/2019 10:45 AM, Wes wrote:
>> Although the manual doesn't say so, according to an ARRL review, the K3S is 
>> specified to have undesired sideband suppression of >50 dB.  ARRL claims an 
>> optimistic >70 dB.
>>
>> So if you are extremely strong at the other guy's place, he might easily hear 
>> an opposite sideband, even though your radio is operating correctly.  Ask him 
>> what the ratio is.
>>
>> Wes  N7WS
>>
>> On 8/28/2019 9:40 AM, Nate Bargmann wrote:
>>> I received a note this morning advising that I should check my ALC as he
>>> is seeing some energy on USB when I check into a 75m voice net on LSB.
>>> I am using an MC-50 microphone and am running the mic gain at 35 and the
>>> compression at 11.  My thinking was that generating opposite sideband
>>> energy would be quite difficult with the K3's DSP.  Am I wrong?
>>>
>>> I'll try working with him some morning and back down the mic gain a bit
>>> and see what that does for him.