[Elecraft] What crystal filters for the K3 are linear phase delay (constant group delay) ?

[Joe Subich, W4TV]

 > Joe is well aware of the issue. Hiss answer that the phase distortion
 > issue trumps S/N ratio.

K1JT is correct as it relates to EME where one does not generally have
strong interfering signals.  Remember the detection bandwidth in WSJT-X
is on the order of a few Hertz - not the 2.8 to 5 KHz audio bandwidth
that would be the case with human decoding of CW or SSB.

Note that K1JT also recommends operating without AGC if possible.
However, when we get to HF with its mixture of weak and strong signals,
narrow filters are sometimes necessary in order to prevent blocking
(AGC and/or ADC overload).

73,

    ... Joe, W4TV


On 4/21/2014 5:28 PM, Jim Brown wrote:
> On 4/21/2014 1:59 PM, Larry Lopez wrote:
>> But what about:
>>
>> very weak signals reducing the bandwidth increases the signal to noise
>> ratio.
>> very strong signals reducing the bandwidth can prevent the DSP chain from
>> desensitizing the receiver and/or saturating the a/d converter.
>
> Joe is well aware of the issue. Hiss answer that the phase distortion
> issue trumps S/N ratio. You may want to study what he has had to say on
> the issue. Joe reads the WSJT list.
>
> 73, Jim K9YC
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