Here I have an elusive schematic of a 20 dB amp at around 20 MHz. It works as a unity gain amp when the control line IFG2 is open. When grounded it amplifies by 20 dB. The diode is a pin diode and supposedly has 83 ohms when the current is flowing through it. The +10 volts comes from a temperature compensated regulator, +15 volts from a normal regulator. This is what's intriguing, why is the base voltage of Q4 actually more than the supply voltage. It's 10.3 V And secondly, what is the purpose of L7 = 22uH, does it defeat the purpose of R32. I'd appreciate any insights.