[Elecraft] [K3] Roofing filters are misunderstood

[Fred Jensen]

I have imperfect recollections that the source of the term "roofing 
filter" came from the idea that the filter put a "roof" over your 
receiver to prevent very strong, off-frequency signals from getting in. 
  You'll need to crank up your imagination here ... similar to the roof 
of your house keeping out things falling from the sky while desired 
things can still enter through the doors.  I did say "imagination." :-)

I do also agree, it's probably not a particularly descriptive name, but 
the filters do have a purpose in SDR's like the K3.  I think most of the 
thread was aimed at the differences between the various filters 
available for the K3.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2014 Cal QSO Party 4-5 Oct 2014
- www.cqp.org

On 5/12/2014 12:01 PM, Bill Turner wrote:

> I still don't get it. What does the word "roof" have to do with
> bandpass? That's where the confusion comes from.
>
> 73, Bill W6WRT
> dezrat at outlook.com