K3 Roofing Filters

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.

K3 roofing filters.

Driving the k3 with more noise made the greatest difference in the plateau effect noted in earlier measurements. A roofing filter is simply a filter in the radio s first if through which all signals must pass before they will be seen by later receiver stages. O needs vhf roofing filters wide cheap or narrow expensive o excellent image rejection o close in dr varies down conversion architecture 9 mhz typical 1 st if o performance near if is not uniform o image rejection near ham bands requires design attention o needs only hf roofing filters narrow cheap. There are recommendations in the k3 owner s manual see crystal filter setup indexed on page 46.

In general you ll want to add 1 2 db for 400 500 hz filters and 3 4 db for 200 250 hz filters. 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. K3 filters and dynamic range. You must have at least one in your k3 and the basic k3 includes the kfla3a 2 7k 5 pole 2 7 khz filter.

Kxfl3 kx3 dual passband roofing filter kit regular price 169 95. Which is yout best choice. The curves below is the response with the k3 if set for 1khz and with the 250hz roofing filter or the 400 hz roofing filter in place. 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.

Icom ic 756 pro ii iii roofing filters. Consider signals falling out of the sky onto the receiver front end. Use vfo a to set the gain in db. But a roofing filter can be equally at home at a low first if if that is how the radio is designed.

Kfl3a 500 500 hz 5 pole roofing filter for cw note that the radio comes with a 2 7 khz roofing filter as standard click on all images to see the photo in full size. Installed 2 8k 1k 400hz 250hz 200hz for cw and digital mode.