400Hz 6-Pole Roofing Filter for K3 Transceiver.
KFL3C-400 Elecraft 400Hz 6-Pole Roofing Filter for K3 Transceiver. This is the most popular CW filter for use with the K3. It is a steep sided 6-pole filter that provides a fine balance between selectivity and tuning around a narrow band sector. As with all Elecraft filters used in the K3, they are automatically selected as the bandwidth is reduced. They can also be manually selected from a simple button press from the front panel,