[Elecraft] 1 Khz filter

[Bill Breeden]

Jim,

I think most K3 owners understand that.  Those who call CQ during 
crowded band conditions also understand that their ears will take less 
of a beating when using a 1 kHz DSP bandwidth in conjunction with a 1 
kHz roofing filter instead of the next wider roofing filter, which, in a 
K3 is often a 2.7 or 2.8 kHz filter.  That's the wonderful thing about a 
K3, the owner can equip it according to his or her personal preference.  
My ears have taking enough beatings over the years from stations outside 
of the filter bandwidth pumping the AGC while using lesser receivers to 
know that I prefer a tight roofing filter bandwidth so that the stations 
outside of my DSP bandwidth have minimal effect on what I am hearing.   
I have used my "Field Day" K3 to call CQ during crowd banded conditions 
before and after I added the 1 kHz filter and have found the improvement 
well worth the price of the filter.  Your mileage may vary.

73,

Bill - NA5DX

On 7/25/2017 10:08 PM, Jim Brown wrote:
> On 7/25/2017 7:11 PM, Bill Breeden wrote:
>> I found that I was missing stations that were calling on the skirts 
>> of my 400 Hz filter, so I added a 1 kHz filter.  When I tune the band 
>> to answer CQs I still prefer listen through the 400 Hz filter. 
>
> It's important to remember that IF bandwidth is determined by DSP, and 
> continuously adjustable. The plug-in filters are ROOFING filters -- 
> their primary function is to protect the DSP from overload by very 
> strong stations outside the bandwidth of the DSP IF. They have the 
> secondary function of adding the filtering provided by the DSP, and 
> when the DSP and the roofing filter are at the same bandwidth, the 
> filter skirts become steeper (sharper).
>
> Bottom line -- we don't need to buy a 1 kHz filter to get 1 kHz IF 
> bandwidth, because the DSP already provides that. This is not your 
> grandfather's radio! :)
>
> 73, Jim K9YC
>
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