Re: [TenTec] Roofing filters

[Bob Henderson <bob@cytanet.com.cy>]

I believe the term was derived because the roofing filter determines the 
largest b/w available.  Subsequent filtering can narrow b/w and can 
improve skirt  gradient but cannot increase b/w.  The first filter has 
therefore applied limits to the system or put a "roof" on it.
That's how it was explained to me many years ago and it seems to work.

73  Bob, 5B4AGN, P3F



w8au@sssnet.com wrote:

> At 10:11 PM 12/24/2003, RON ZOND wrote:
>
> > Please explain the term "roofing filter". What type of filter is it, 
> > and how
> > does it get its name? How does it differ from the standard filters with
> > which I am familiar?
>
> In the Microwave world, "roofing filters" refer to low pass filters
> with a high frequency cutoff.   (symbolic of a "roof")
> I have noticed all the talk about roofing filters with respect to
> receiver front ends, and have not questioned it as you have, since
> I knew what was being spoken of.
>
> But your question is a good one.  How did a basic "bandpass"
> filter become known as a roofing filter?   Ham interpretation?
>
> Perry     w8au
>
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