[Elecraft] adding 250Hz filer, any improvement?

[Dave Hachadorian]

I had both filters installed for a while.  They both work equally well. 
The 250 produces a beautifully symmetrical, optimal width, spectral plot on 
the MMTTY FFT display for RTTY, so I decided to standardize on that filter, 
and sold the 400. Now I have 250's in both of my K3's.  I told the K3's 
that the filters were 400's, so they switch in at that dsp bandwidth.


Dave Hachadorian, K6LL
Yuma, AZ




-----Original Message----- 
From: Scott Ellington
Sent: Tuesday, February 08, 2011 12:07 PM
To: Elecraft Reflector
Subject: Re: [Elecraft] adding 250Hz filer, any improvement?

QRM levels are generally much lower outside EU or NA.  Years ago, I did a 
CW contest from ZL with a TS-50 and a single 500 Hz filter.  That would 
have been woefully inadequate in NA, but it was fine there.  So, the 
question I would ask is whether anyone in a non-EU or NA QTH has compared 
the K3 400 Hz filter with narrower DSP with the 250 Hz filter.  Surely, the 
400 Hz fliter +DSP would be far superior to that old TS-50, so I would 
expect it to be fine.  Note that the K3 "250 Hz" filter is really about 370 
Hz wide, compared to 435 for the "400 Hz" one, so the difference isn't that 
great, anyway.

Perhaps Jorge can check this out in the next contest:  Set the "I" filter 
to 400 Hz, and the "II" filter to 250 Hz, both with the 400 Hz xtal filter. 
I'd be interested in the results.

73,

Scott  K9MA



On Feb 8, 2011, at 11:49 AM, Jorge Diez - CX6VM wrote:

> Hello,
>
>
>
> I have both KFL3A-400 (400 Hz 8-pole) and KFL3A-1.8K  (1.8 kHz 8-pole)
> filters in my K3.
>
>
>
> If I add a KFL3A-250 (250 Hz 8-pole) filter I will notice it better to 
> use
> in contests?  Or with the 400Hz is enough?  Notice I am not in USA or EU
> with strong stations near me, I don´t have the QRM this big populations
> have, trying to reduce the splatters.
>
>
>
> 73,
>
> Jorge
>
> CX6VM/CW5W
>
> k3 #4077

Scott Ellington
Madison, Wisconsin
USA



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