[Elecraft] KX3: Is this a serious error in KX3 Firmware affecting the IQ output?

[Don Wilhelm]

Tom,

Look up Weaver demodulation on the web and you will see that when that 
demodulation technique is used, there will be content in the low 
frequency portion of the audio and aalso on the high end, with little 
signal in the middle of the audio spectrum.
It should happen in both LSB and USB, and I believe the starting point 
is for a bandwidth of less than 1.8 kHz.

It seems to me that the 'center of the passband' should be about halfway 
between the two peaks, but a closer study of Weaver demodulation may 
give you a better clue to deciding how it should be displayed.

73,
Don W3FPR

On 9/22/2014 7:50 PM, Tom Blahovici wrote:
> Hi
> If this is the case is there any way to determine exactly where or when this happens? Does it happen as I described?  Can one use the BW command to  actually compensate?  Does it occur in USB only?
> Thanks for any insight.
> 73's Tom
>
> On Sep 22, 2014 7:25 PM, Don Wilhelm <w3fpr at embarqmail.com> wrote:
>> Tom,
>>
>> I don't know the answer, but what I can inject is the fact that the KX3
>> shifts to Weaver demodulation at some point, it may be at 1.7 kHz.
>> That would affect the signal peaks without substantially changing the
>> sound of the signal on the KX3.
>>
>> 73,
>> Don W3FPR
>>
>> On 9/22/2014 7:13 PM, tomb18 at videotron.ca wrote:
>>> Hello,I received reports recently about the signal peaks that are seen in software based panadapters appear to shift by approximately 1.25kHz when the bandwidth control is changed from 1.8 to 1.7. in USB mode on the K3
>>>
>>>
>>> At 1.8 the IS command returns 1500 in USB and the BW command returns BW0180
>>> AT 1.7 the IS command returns 1500 in USB and the BW command returns BW0170 which is normal behavior.
>>>
>>>
>>> I have investigated this and it indeed happens when the bandwidth is changed from 1.8 to 1.7
>>> The sound of the signal nor the tuning of the radio is changed. However, a QSY to the original peak will detune the signal.
>>> This has been confirmed in Win4K3Suite, NAP3 and HDSDR.
>>>
>>>
>>> Can someone check this please on the PX3?
>>> This is on the latest firmware of 2.19
>>>
>>>
>>> Thanks, Tom va2fsq
>>>