On Mon, Apr 7, 2025 at 09:47 PM, Terry W7AMI wrote:
I wouldn't worry to much about the impedance miss match for doing an
alignment. Once you are past the 1st RF amplifier it won't make any
difference.
The impedance presented to the front-end can affect tuned-circuit tracking and Q in the RF amplifier, which can affect receiver sensitivity. It can affect receiver selectivity if the tuned circuits have high Q and the tracking is off. Even if the car antenna is resonant, the impedance at the receiver input can be far from 50 ohms due to impedance transformation from the low-capacitance cable, which isn't anywhere near 50 ohms.
Brian
