[Elecraft] Roofing Filters

[Ron D'Eau Claire]

I see that Lyle (Mr. DSP) stepped in with the answer I couldn't have given
you anyway <G>. That's the beauty of this reflector: lots of expertise and
resources. I seldom "answer" a question without learning something myself! 

Someone else dropped me a note reminding me that Wayne discusses roofing
filters on the Elecraft web site and, in particular how he addressed the
design issues of employing them in the K3. That FB write up is here:

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

Ron AC7AC



-----Original Message-----
From: Dave Van Wallaghen [mailto:w8fgu at comcast.net] 
Sent: Wednesday, February 20, 2008 2:21 PM
To: 'Ron D'Eau Claire'; elecraft at mailman.qth.net
Subject: RE: [Elecraft] Roofing Filters


First, thank you Ron for putting that in a very comprehensive manner that
even I could understand ;-) As usual, you've turned on the "light bulb".

Now, when I purchased my K3 and debated on my purchase of the roofing
filters, I spoke with a few hams who said that the roofing filters were
primarily for blocking out close in and powerful signals and that if I
didn't have that problem where I live, that the standard DSP filter with the
standard 2.7khz filter would probably suffice. And that is what I did.

But I wonder (always dangerous), if operating on some of the noisier bands,
would there be a benefit to using a narrower filter to cut down on the
amount of energy hitting the DSP in order to help with digging out weak
signals? Or is that not a consideration with this particular implementation
of DSP in the K3?

As is, it has been fun playing around with digging out weak signals and
enhancing them. I need to get a better antenna to rig switching setup so I
can make a/b comparisons with my K2.

Thanks in advance,
Dave W8FGU

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