November 2024

What is a Roofing Filter?

On a recent club net, one of the stations checking in, asked about roofing filters. The roofing filter in a radio is the filter through which the first IF must pass. According to Elecraft, the term "roofing filter" has most often been used in relation to triple- or quadruple-conversion receivers. Such receivers have an IF above the highest RF band covered; it's typically something in the range of 30 to 70 MHz or higher. But "roofing" as a term should be interpreted as "protective," not "high in frequency." A roofing filter protects later stages, including amplifiers, mixers, narrower filters, and DSP subsystems, just as the roof on your house keeps rain out of all of the rooms.


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Roofing Filters in Context

A YouTube video discussing adding a roofing filter to enhance CW operation: https://youtu.be/CIRJqBGRCUI?si=1l8_pj6VfnoSKcSi

Demo of roofing filter on 20 meters: https://youtu.be/mKnoxmjNstI?si=ef7yik0zRg_touab

A YouTube video about installing a roofing filter in a Yaesu radio: https://youtu.be/5Af9Je-JrNw?si=pnyGyU0wKToQGcWH

Here's another video about the difference between roofing filter and DSP filter: https://youtu.be/_FRkpfGh7Ik?si=g6LTjqKtFgmMhSRR

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