[Elecraft] K3: APF effectiveness

[Pete Smith]

Heck, I can hear thiose phantoms with the radio off (tinnitus).  
Fortunately it subsides in the presence of other noise - just like with 
the APF, which works FB for me on the low bands.

73, Pete N4ZR

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On 1/25/2011 7:55 PM, Barry N1EU wrote:
> What you're describing ("hear signals that aren't even there") sounds to me
> like the APF is working just as intended.  You're hearing faint ringing at
> your sidetone frequency when no signal is present.  When a signal is present
> and tuned in, it will have precisely that same tone but will pop further out
> of the noise than that "phantom" signal.  It just demands a little practice
> and patience along with fine tuning.
>
> If someone wants a lower Q APF with less gain, they should try a dsp width
> of 50hz without APF.
>
> 73, Barry N1EU
>
>
> Ralph Parker wrote:
>>> ...perhaps less gain and a little wider BW
>>> or give the user the tools to do it ourselves.
>> I was thinking exactly that myself last night on 160m - no problem with
>> the
>> bandwidth, but I'd gladly give up a db or two of APF gain to reduce the
>> ringing.
>> Because of the ringing, I can hear signals that aren't even there!
>>