[Elecraft] KX3 Filter Blow-By

[Wayne Burdick]

You might see suppression of as high as 70-75 dB, but it varies a bit per-band and with signal pitch. The worst case will still be ~50-55 dB as with other receivers using the same direct-conversion I/Q architecture.

73,
Wayne
N6KR

On May 6, 2013, at 4:41 AM, Bill W4ZV <btippett at alum.mit.edu> wrote:

> What is the OSB suppression after calibration using this procedure?
> 
> 73,  Bill  W4ZV
> 
> 
> wayne burdick wrote
>> Hi Jim,
>> 
>> This is most likely related to opposite sideband suppression, not  
>> filter blow-by. Nominal factory calibration results in OSB suppression  
>> of around 55-60 dB. You can improve on this using a new procedure we  
>> developed a month or so ago. It requires a strong signal source on  
>> each band to be optimized. I can send you the firmware and  
>> instructions if you're interested.
>> 
>> 73,
>> Wayne
>> N6KR
>> 
>> On Oct 8, 2012, at 10:46 AM, 
> 
>> Jimk8mr@
> 
>> wrote:
>> 
>>> A recent KX3 owner (# 1677), I've noticed hearing out of passband   
>>> signals
>>> from loud CW stations. I can hear such stations up to several KHz   
>>> away. I
>>> suspect the range is limited by the audio response of the system,   
>>> including
>>> my ears. Both sides of zero beat, though less so on the opposite  
>>> side  of
>>> the zero beat.
>>> 
>>> In the CA QSO Party this weekend, maybe the loudest 10% of the  
>>> stations on
>>> 10 CW Saturday afternoon were leaking through. (I've heard the  
>>> leakage on
>>> other  bands as well.)
>>> 
>>> I don't have any roofing filters. (I figured any stations weak  
>>> enough  for
>>> me to need the filter to hear, would never be able to hear me anyway).
>>> 
>>> Is this normal, or is there some shielding or other issue affecting my
>>> unit? (It is a kit version).
>>> 
>>> 
>>> 73  -  Jim  K8MR
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> 
> 
> 
> 
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