500MHz RF input impedance mismatch
An incorrect impedance matching has been found throught schematic
The RF input jack is connected to a Minicircuit's RF transformer line balun, the secondary is connected to a 100ohm resistor (R76). The equivalent circuit after R76 has an impedance greater than 100ohm. The configuration of the RF tranformer is a "Guanella Transformer" (see ) which has an equivalent impedance on the primary equal to the impedance of the secondary (1:1). Since R76 has 100ohm of impendace, an impedance mismatch occurs. Minicircuit contacted , they agrees.
 Dear Mattia,Thank you for your query.
We have reviewed the diagram you provided and in order to be correctly matched the secondary impedance would need to be 50 Ohm differential. As the following circuits are high impedance we would agree that a 50 Ohm resistor should provide a better match than 100 Ohms.