K9DP QRP BCI Filter
$4.99 – $39.99
- Designed to help HF radios and receivers that struggle with front-end overload from AM broadcast interference, such as Xiegu radios X6100, X5105, G90, G106 and SDR receivers.
- Lightweight and portable design, only 3 inches (77mm) in length and weighing just 20 grams. Perfect for Parks on the Air (POTA), Summits on the Air (SOTA) and Field Day.
- Tested up to 20 watts with SSB, CW and digital FT8.
- Quick and easy to build, see online instructions here.
- High quality C0G (NP0) capacitors and Micrometals toroids.
All kits and prebuilt filters sold on this website, Ebay and Amazon are Version 2 now. Version 2 has much higher AM band rejection. If you specifically want version 1 please contact me.
The K9DP QRP broadcast interference (BCI) filter kit allows QRP (low-power) amateur radio operators to reduce or eliminate unwanted broadcast interference in their signals. Primary designed to help HF radios and receivers that struggle with front-end overload from AM broadcast stations, such as Xiegu X6100, X5105, G90, G106 and SDR receivers.
This lightweight and portable kit is ideal for use in field operations such as Parks on the Air (POTA), Summits on the Air (SOTA), and Field Day. It has 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.
The kit includes all of the materials and components needed to build the filter, including BNC connectors, capacitors, enameled 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 female BNC connectors.
Overall, this kit is 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.
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.
Video by Steve KM9G testing version 2 of the filter.
Video by Thomas K4SWL testing the filter in the field.
Video by W6IWN
|Kit or Prebuilt
Kit, Prebuilt, Board Only
Female BNCs, Male/Female BNCs