Sherwood Roofing Filter

Transmission is not changed as it does not pass through the roofing filter.

Sherwood roofing filter.

The sherwood 600 hz cw roofing filter fixed the r 4c in 1976. These mod s do transform the receiver to a completely higher level and are worth the investment. 80 85 db 2 khz contest community examples. The roofing filter mod inserts a narrow band crystal filter between the rf assembly and the if board.

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. Elecraft k3 now also offers multiple roofing filters in 2008. O nc0b rob sherwood. Click to view or to save right click save target link.

The filters will reduce qrm leakage overload and eliminate blanker false triggering from adjacent stations. Ideal for dx and contest work. The sweet thing about the r 4c is that it has all of the sherwood mod s including the cw ssb roofing filters. Variable bandwidth can be obtained by offsetting first and second if filters with passband tuning control.

Roofing filters transmitted bw receiver performance. The overall shape factor is better than 1 5. 80 db 2 khz cw 70 db ssb o w8ji tom. Read about the ultimate selectivity number that appears in the sherwood test report.

Contesters dxers pileup operators need the best receiver possible especially for cw operation the sherwood 600 hz cw roofing filter fixed the r 4c in 1976 and the ten tec orion put that concept in a commercial design in 2003. Maximum skirt selectivity with maximum intelligibility. Mst monday friday. Powerpoint acrobat.

Yccc boxborough ma 2008. If a roofing filter is observed to improve the selectivity of your transceiver then the if filtering was inadequate in the first place compared to better receivers. Now the elecraft k3 also offers multiple roofing filters of am ssb cw bandwidths. Ground screen replace compliment a radial system.

Reducing the bandwidth at this point in the radio helps to keep strong off frequency signals out of the second mixer where they can cause intermodulation. Dayton contest university 2009. Slide show only ppt or pdf click to view or to save right click save target link.