[Elecraft] K3 QSK

[David Gilbert]

With all the discussion about what may or may not be a "thump" and what 
it actually sounds like, I'm a bit surprised nobody has bothered to post 
a simple recording of it so that the rest of us don't have to guess at 
what you're hearing. 

Dave   AB7E


Merv Schweigert wrote:
> I posted that I could not duplicate the thumps on #2603.  After trying a 
> few more times
> I am hearing exactly what Mike describes, and after talking with Toby, 
> it may be a
> difference in terminology, at least on my part.  I hear the same thing 
> but I describe it
> as pops or clicks,  and as Mike says it seems to be from the high 
> background noise,
> not that I have a high level of background noise, mine is S2,  but from 
> the high level
> of the RF gain control,  I never hear these artifacts due to the way I 
> use the AF/RF
> controls,  my AF is usually set about 12 o'clock and RF about the same,  
> I use the
> RF as the gain control,  I think this was described many times in the 
> past by others.
> The thump is also noticeable if there are signals on the band inside the 
> passband,  I have
> the monitor volume set high enough that it equals those signals in 
> volume so the
> thump is less noticeable.
> Some of these anomaly are hard to define,  and finding a word to 
> describe the sound
> is difficult.  To me its pops or dull clicks,  others its thumps, but we 
> agree we are
> hearing something.
> 73 Merv KH7C
>
>   
>> I can duplicate what might be called QSK thumps with high volume settings
>> and using earphones or speakers. I have the choke change but have not
>> modified low frequency response with larger caps. I think the thumps come on
>> key up not key down.
>> Everything is fine when I have the volume set at a normal level. I begin
>> hearing thumps at a volume setting of 11 O'Clock.
>>
>> What I believe I am hearing though is not an artifact but just high band
>> noise between dits that give an impression of thumps. The high band noise is
>> being gated by TR switching. I suspect if I didn't live in a high noise
>> environment I wouldn't here this.
>>
>> Mike Scott - AE6WA
>> Tarzana, CA (DM04 / near LA)
>> NAQCC 3535
>> K3-100 #508 / KX1  #1311
>>
>> I sat down in TEST mode and tried all the combinations you mentioned again
>> and can't produce thumps. I even tried every possible combination of AF/RF
>> and MON levels with no thump. 
>>
>> So I'm sri to say obviously something is different between our rigs and
>> setups, but I can't imagine what. 
>>
>> The only audio mod involving a change on the main board is to change a
>> choke, not a cap. It reduces the resistance of the choke to improve the
>> voltage regulation at the AF Amp. I've made that too. When I said my K3 was
>> "stock" Elecraft, it does have the Elecraft-approved and documented mods
>> made while writing the app notes. 
>>
>> I asked wondering if the capacitor changes some have made to improve the
>> low-frequency response were making the low frequency 'thumps' stronger and
>> audible. If you've not done them, we should have similar rigs. 
>>
>> Ron AC7AC
>>
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>
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