The SBL-1 wants to see +7 dBm at 50 ohms, which comes out to 500 mV RMS. http://www.vk6fh.com/vk6fh/RF%20MIXERSdiode.htm To convert RMS to peak-peak, multiply by 2.82. Thus, 1.41 V p-p. http://wiki.answers.com/Q/What_is_the_conversion_for_rms_voltage_to_peak_to_peak_voltage 73, Jim, KR1S http://qrp.kearman.com/