This roofing filter substantially reduces the third order intermodulation from multiple strong signals in the 2 to 20 kHz region either side of the tuned frequency. It has much of the benefit of the IF Noise Reduction Mod and in addition it reduces the close in IMD. This is particularly important for stations with big antennas or stations which regularly receive loud signals.

This is a plug-in, no-solder mod that can be easily removed. The roofing filter also works in the Mark V and Mark V Field, except it requires soldering two connections.

Please see our document titled "A Few Words About Roofing Filters" for more details.

Note: This unit cannot be installed along with the Inrad FT-1000MP IF Noise Reduction Mod. Only one or the other can be used.

The product has been reviewed in Feb 2005 QST and Jan 2005 RadCom. (Reproduced through the kind permission of the ARRL and the RSGB.)

• FT-1000MP: Installing the Inrad Roofing Filter Mod