Receiver Roofing Filter

Icom ic 756 pro ii iii roofing filters.

Receiver roofing filter.

The down conversion type receiver construction is similar to the ftdx5000. Other radios with similar performance. O roofing filter width test tone spacing width o test tones are attenuated by roof o dr3 value is limited by upstream components includes the roof in band. Drake r7 and tr7 ic 781 collins 75s 3b c ts 930 ft 1000x t t omni v or vi.

A roofing filter is a type of filter used in a hf radio receiver it is usually found after the first receiver mixer. A roofing filter is one which is placed ahead of the main gain stages in a if stages of a superheterodyne receiver. The down conversion type receiver construction is similar to the ftdx5000. Roofing filters installed in the main and sub receivers are the 12 khz 3 khz and 600 hz plus a 300 hz filter is installed in only the main receiver.

Rodhe recent advances in receiver design qst nov 1992. For ssb a single 15 khz roofing filter is adequate such as in the icom 756 pro ii pro iii with a close in dynamic range of 75 db. Three optional roofing filters are available the 300 hz ysu xf 129cn for the sub receiver and the 1 2 khz ysu xf 128sn for the main and ysu xf 129n for the sub receivers also only available by. The goal of a roofing filter is to limit the passband of the first intermediate frequency if stage.

These roofing filter can help reduce the third order intermodulation from multiple strong signals in the 2 to 20 khz region either side of the tuned frequency. By incorporating a filter early in the gain stages of the receiver strong off channel signals can be removed or reduced in strength so that they do not overload the later stages prior to the main filter. Crystal roofing filters produce phenomenal multi signal characteristics. For more detailed information on roofing filters please read a few words about roofing filters this mod is significantly more challenging to perform than inrad s other roofing filter kits and.

The goal in applying roofing filters to a price signal is to simultaneously attenuate high. Strong signals outside the channel which may cause overloading and distortion by the following amplifier stages and mixers are blocked. It depends on your mode of operation. How many roofing filters are needed.

Crystal roofing filters produce phenomenal multi signal characteristics. Roofing filters are a type of bandpass filter conventionally used in hf radio receivers in the first if stage to limit the frequency spectrum passed on to later stages in the receiver.