Hi Alberto I have designed a simple frontend with a bandpass filter in several versions of which one for 3 to 8 MHz using a MAR-4 for amplifier doing about 15 to 20db gain. See http://www.gnuradio.nl/pascal/BasicHFfront.html
You welcome to contact me if you are interested. Pascal _______________________________________________ Discuss-gnuradio mailing list Discuss-gnuradio@gnu.org http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
