Cross Country Wireless have just released a HF Upconverter. This will allow HF or VHF SDR receivers such as the RTLSDR dongles, Funcube or our own SDR-4+ receiver to work on HF, LF and VLF.
Unlike other upconverters currently available we have added the RF protection features from our SDR-4+ receiver including an antenna isolation transformer and RF over-power protection. This protects the SDR receiver or dongle and the attached PC from damage caused by static electricity charges on the antenna or nearby high power transmitters.
There are two versions of the Upconverter. One has a 125 MHz local oscillator and the frequency range is 12 kHz to 45 MHz. This is intended for use with the RTLSDR and Funcube dongles.
The other version has a 10 MHz local oscillator and is designed for use with the SDR-4+. This has a frequency range of 12 kHz to 1.6 MHz.