[Elecraft] [K3] Roofing filters are misunderstood

[Greg]

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




On Mon, May 12, 2014 at 9:45 AM, Jack Brindle <jackbrindle at me.com> wrote:

> Jerry,
>
> Why do you say it has been corrupted? This is exactly the purpose for the
> Roofing Filters in the K3.
>
> Jack B, W6FB
>
>
> On May 12, 2014, at 9:33 AM, Jerome Sodus <jsodus at comcast.net> wrote:
>
> > Hello Bill,
> > The term "roofing-filter" made sense back in the 1980's when I designed
> > roofing-filters at 70 MHz.
> > Bandwidths would be in tens of KHz.
> > The purpose then was to protect downstream circuitry by rejecting very
> > strong out-of-band signals that could cause overload; selectivity was not
> > the purpose.
> > Selectivity was done further downstream.
> > So the term has become corrupted over the years.
> > 73 Jerry KM3K
> >
> >
> > -----Original Message-----
> > From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of
> Bill
> > Turner
> > Sent: Monday, May 12, 2014 1:07 AM
> > To: elecraft at mailman.qth.net
> > Subject: Re: [Elecraft] [K3] Roofing filters are misunderstood
> >
> > ORIGINAL MESSAGE:          (may be snipped)
> >
> > On 5/11/2014 7:25 PM, Fred Jensen wrote:
> >> I too think roofing filters are really not well understood.
> >
> > REPLY:
> >
> > A large part of the misunderstanding is due to the name. Whoever chose
> > the name "roofing" did a great disservice. A better name would simply be
> > it's function:  1st I.F. filter.
> >
> > That's what it is and that's what it does.
> >
> > I have always thought that "roofing" was a marketing ploy to imbue it
> > with some kind of magical powers.
> >
> > 73, Bill W6WRT
> >
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