How do you compensate for the derating with frequency change? I am using a techtronics scope to measure voltages at 10-30 megs and I see from the manual that voltage derates up to 5 fold from 1 to 9 MHz and continues thereafter. How do you take any meaningful measurement of voltage without an accurate reference voltage at near the same frequency? I need to measure the voltage generated by a heterodyne oscillator circuit that puts out 5 different selectable frequencies depending on the band selected. The frequencies range from 10-35 MHz, and the voltage range from 6-11 volts. When I measure them, they all come up at nearly half what is specified, but I am thinking based on the manual for the Techtronics probe, the measurements will of course be low.