I believe the promised X2 signal enhancement by the transformer isn't so essential for the amplifier, apart from this detail it's a buffer amplifier with high input impedance.
I believe the promised X2 signal enhancement by the transformer isn't so essential for the amplifier, apart from this detail it's a buffer amplifier with high input impedance.
The diode is protecting the FET against ESD and other possible input overvoltage.
Voltage must be below 6 dB, hopefully it's greater than 0 dB. Antenna effective height and output impedance is the more interesting part of the problem.
You mean the gain of the amplifier, right?
0db is no gain, so what is the meaning of having the preamp in place? Maybe all the voltage gain depends on the transformer and the transistors are there as current amplifiers? (a guess)