200 Hz 5-pole filter

[Wes (N7WS)]

Why?

On 7/26/2015 2:02 PM, Bill Breeden wrote:

>
> Since Sherwood's Dynamic Range Narrow Spaced measurement is of great interest
> to CW operators, it only makes sense to make the measurement using a CW
> filter, optional or not.  The measurement would be meaningless to CW operators
> if made using the stock sideband filter.
>
> 73,
>
> Bill - NA5DX
>

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[Bill Breeden]

Wes,

Rob Sherwood's presentation at the following link answers the "why"
question a lot better than I can:

http://www.sherweng.com/RochesterMN2009/NC0B-W0DXCC-4dRochester_MN.pdf

At the following link, Eric explains why selecting a narrow filter for
CW operation in a K3 offers superior performance over selecting a wide
(sideband) filter and adjusting the DSP to a narrow bandwidth:

http://www.elecraft.com/K3/Roofing_Filters.htm

The point I am trying to make is that a K3 with a 2.7 KHz filter and the
DSP cranked down to 400 Hz will not perform as well for CW during
crowded band conditions as a K3 with a 400 Hz filter.

73,

Bill - NA5DX



*Wes (N7WS)*wes at
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/Sun Jul 26 19:48:20 EDT 2015/

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------------------------------------------------------------------------

Why?

On 7/26/2015 2:02 PM, Bill Breeden wrote:
>//>/Since Sherwood's Dynamic Range Narrow Spaced measurement is of great
interest />/to CW operators, it only makes sense to make the measurement using a CW />/filter, optional or not. The measurement would be meaningless to CW
operators />/if made using the stock sideband filter. />//>/73, />//>/Bill - NA5DX />



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[Elecraft mailing list]

Agreed (but not "meaningless)!  
The additional narrow cw filters clearly provide a BIG improvement over the wider SSB Filters(e.g., the 400 HZ filter shows a 16 db improvement in 3IMDDR and 35 db improvement in BDR over the stock 2700 Hz SSB Filters).  Meaning it "is" very helpful to cw operators to know how the radio performs with the more narrow cw filters.  The ARRL Table in the K3 2009 review shows the figures.  Can't tell how the rig would have tested if the DSP was narrowed to, say, 400 HZ while using the wider SSB filter....
Bob/AA6VB
      From: Bill Breeden <[hidden email]>
 To: [hidden email]
 Sent: Sunday, July 26, 2015 2:02 PM
 Subject: Re: [Elecraft] 200 Hz 5-pole filter
   

Since Sherwood's Dynamic Range Narrow Spaced measurement is of great
interest to CW operators, it only makes sense to make the measurement
using a CW filter, optional or not.  The measurement would be
meaningless to CW operators if made using the stock sideband filter.

73,

Bill - NA5DX


On 7/25/2015 1:47 PM, [hidden email] wrote:

> Message: 27
> Date: Sat, 25 Jul 2015 11:04:20 -0700 (MST)
> From: XE3/K5ENS via Elecraft<[hidden email]>
> To:[hidden email]
> Subject: Re: [Elecraft] 200 Hz 5-pole filter
> Message-ID:<[hidden email]>
> Content-Type: text/plain; charset=us-ascii
>
> Apples and oranges.
>
> The K3 is still no 2 with the 200 Hz 5-pole filter.  You just can no longer
> buy the radio with that filter.
>
> I have always found it a little strange that Sherwood never stated that
> the filters used in his test were optional on the K3?
>
> If the K3 was tested with the stock filter it may make it into the top 10.
>
> Don't get me wrong I have a K3S on order.  I'm just looking at the data

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[Jim Brown-10]

On Sun,7/26/2015 5:33 PM, Bill Breeden wrote:
> The point I am trying to make is that a K3 with a 2.7 KHz filter and
> the DSP cranked down to 400 Hz will not perform as well for CW during
> crowded band conditions as a K3 with a 400 Hz filter.

Hi Bill,

That point is not lost on anyone, and is the reason that serious
contesters use narrow roofing filters. I said exactly that in my earlier
response.  But the point that you are missing is that the K3, K3S, and
KX3 are complete radios with the stock 2.7 kHz 5-pole or 2.8 kHz 8-pole
roofing filters, and are comparable to the receivers we have used for as
long as I have been a ham (60 years).

What's different are 1) the some of the hardware with which those older
radios and the K3/K3S/KX3 are built. Our older receivers used physical
coils and capacitors in the IF, while these newer ones simulate those Ls
and Cs in DSP; 2) the system architecture that Wayne developed (for
example, his choice of IF frequencies, his methods of reducing phase
noise, keying transients, etc.; and 3) they're a lot better radios that
most of those older ones.

A ham who doesn't participate in major contests is unlikely to need
anything more than the 2.7 or 2.8 kHz roofing filter.

73, Jim K9YC


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[Petr, OK1RP/M0SIS]

Hi all,

I found over there the Plots for the Elecraft filters
http://www.elecraft.com/K3/K3_filter_plots.htm
but KFL3A-200 is missing.
Is it possible to find somewhere the Plot also for this filter please?

Thank You,

73 - Petr, OK1RP