9:1 Impedance Converter (BALUN) for RTL-SDR with BNC Connector

9:1 Impedance Converter (BALUN) for RTL-SDR Long Range Antenna with BNC Connector

This impedance converter can be used with a long wire antenna (or any wire) for HF reception on an RTL-SDR with an upconverter. The impedance of a long wire antenna is approximately 450 ohms (very roughly, as impedance varies with frequency and length). The 9:1 BALUN allows for matching with a 50-ohm receiver, which is close enough to the 75-ohm input of the RTL-SDR. A small amount of impedance mismatch is insignificant for RX, but larger mismatches can lead to degraded reception.

With a working frequency of 100K-50MHz, small dimensions, and easy mounting and demounting, it is suitable for outdoor and QRP usage.

Note: For long-term outdoor use, the top and bottom covers of the casing must be sealed and secured with silicone.