[Elecraft] [K3] Roofing filters are misunderstood

[Jack Brindle]

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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