A manual #antennatuner opens up for a lot of fun 🤩

With a VNA you can watch real-time what happens when you adjust the inductance and capacitor dials, gradually closing in on the desired 50ohm.

Did you notice something funny as I just did? I’m sweeping from 6.9-7.1MHz and initially the 270ohm load impedance shows up as a single dot when the tuner is in ‘bypass’ mode.
Once I switch the tuner to ‘inline’, I get a small line instead. This is the frequency response of the matching network (a T-section) inside the tuner itself.

Had this been a real antenna with its own frequency response, and not just a 270 ohm resistor, the final bandwidth of the system would have been a combination of the antennna and the matching network.

#hamradio #testandmeasurement #hamr #mfj #nanovna #rfengineer