[Elecraft] Re: filter selection

[Stan Rife]

I'd like to add that, I personally, was initially confused by all of the filter selections and was totally ignorant on the subject of "roofing" filters. But after reading a lot of the posts and asking some questions, I think I have a handle on it enough to make an informed decision for myself on what I might need as far as these filters go.
   
  Like Wayne stated, these various selections are an end result of what different people like, and have requested in the past. So now these options are available. One person might like 200hz, and another 250hz. It may be somewhat intimidating to the un-initiated (me for sure), but this list and Elecraft have always been here to clarify and answer our questions. I hardly believe that it will intimidate anyone to the point that they will not buy a K3.
   
  And if anyone thinks that it is unecessarily complicated, that is their opinion, but in the end I doubt that it will affect your paycheck any.
   
  Stan Rife
  W5EWA
  Houston, TX
  K2 S/N 4216
  

wayne burdick <n6kr at elecraft.com> wrote:
  Bill Tippett wrote:

> My point is that you introduce unnecessary complexity with the vast 
> number of roofing filters. 400 vs 500, 250 vs 200, etc.

We're providing a range of options so the customer can decide which 
they want. We may add supplemental information to the order form to 
make decisions easier, but we're not likely to reduce the number of 
filters offered.


> As one example here are Elecraft's own specs for the 400 8-pole versus 
> 250 8-pole:
>
> Filter 6 dB BW 60 dB BW
>
> KFL3-400K 435 Hz 935 Hz
> KFL3-250K 370 Hz 785 Hz

The reason we offer both of these INRAD filters is that they're both, 
historically speaking, very popular. I agree that the frequency spacing 
of these filters could be clarified in their literature, but again, we 
offer them because our customers asked for them, and we're passing 
along the model numbers used by INRAD.

We offer our own narrow filter (200 Hz) for those who really want to 
maximize rejection of unwanted signals in CW and data modes. Such 
narrow bandwidths have been very popular over the years, including in 
the K2.


> In my opinion these filters are redundant and unnecessarily complicate 
> the ordering process. 65 Hz difference in 6 dB BW is hardly worth 
> bothering with, especially since both are 8-pole and their IMD/BDR 
> performance is likely to be identical.

As I explained above, this is a somewhat anomalous historical 
situation. If INRAD would like to create alternative filters with 
different specs, we're open to offering them.


> It's your decision of course but I'm a believer in "keep it simple". 
> I would offer only the best filter for a given BW, predetermined by 
> Elecraft and based upon actual IMD/BDR measurements inside the K3.

Eventually we'll have such measurements. For now, we're not about to 
limit anyone's personal choice.

We'll also provide great leeway in letting customers change their order 
if new information causes them to rethink their filter complement.

73,
Wayne
N6KR


---

http://www.elecraft.com

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