The K9DP QRP broadcast interference (BCI) filter allows QRP (low-power) amateur radio operators to reduce or eliminate unwanted broadcast interference in their receive signals. Primary designed to help HF transceivers and receivers that struggle with front-end overload from AM broadcast stations, such as Xiegu X6200, X6100, X5105, G90, G106 and other SDR transceivers or receivers.
This lightweight and portable filter is ideal for use in field operations such as Parks on the Air (POTA), Summits on the Air (SOTA), and Field Day. They have been tested at power levels up to 20 watts with SSB, CW, and digital modes, and its small size and low weight make it easy to take with you wherever you go. Measuring only 3 inches (77mm) in length and weighing just 20 grams, it's a convenient choice for on-the-go operations.
Available as a complete built filter or for those with a soldering iron, the kit option includes all of the materials and components needed to build the filter, including BNC connectors, capacitors, enamelled wire, toroids, and a printed circuit board. The high quality online instructions provided with the kit will guide you through the process of soldering the components onto the board and assembling the filter, step by step. Once the filter is built and tested, it can be easily attached inline with your radio equipment using the BNC connectors.
Overall, these filters are a great way for radio operators to enhance their radio’s performance and improve their communication experience. These filters have a 50Ω impedance and are symmetrical, so it's not important which end is the input or output.
Check out the videos in with the photos on how they work.
Caution: High SWR can damage the filter. The filter should be inserted inline between the transceiver and tuner, rather than between the tuner and antenna. If your radio has an internal tuner, be sure to use a resonant antenna or an antenna with a matching circuit, such as an EFHW (end fed half wave), in combination with the filter.
