While o find SWR useful, I also show the smith chart, phase and log mag. I set the SWR to a wider range, 10:1 and use log mag to focus on the useful 3:1 range as essentially they are the same measurements. The smith chart is probably the most revealing as it shows what I need to do to tune the antenna. Whether or not the antenna needs capacitance, inductance, or is resonant but a higher or lower impedance feed with a transformer. The phase also assists with finding resonance in the antenna and match unit.
@@HamTechRadioScannerDrones we had a centre dipole for 80m we were setting up for a friend of ours. It was a little close to the ground that the impedance at resonance was too low and so they couldn’t get a decent SWR. They were shortening / lengthening. Nothing was working Having the NanoVNA with a smith chart, it showed that the antenna was closer to 20 ohms at resonance. I got them to lengthen one end and shorten the other moving the feed point slightly off centre and increasing the feed point impedance without screwing up the resonance. If you’re building a mag loop this is really important as resonance is key for efficiency. You want to find resonance first then match the feed to the loop
While o find SWR useful, I also show the smith chart, phase and log mag.
I set the SWR to a wider range, 10:1 and use log mag to focus on the useful 3:1 range as essentially they are the same measurements.
The smith chart is probably the most revealing as it shows what I need to do to tune the antenna. Whether or not the antenna needs capacitance, inductance, or is resonant but a higher or lower impedance feed with a transformer. The phase also assists with finding resonance in the antenna and match unit.
Hi great info thanks .
@@HamTechRadioScannerDrones we had a centre dipole for 80m we were setting up for a friend of ours. It was a little close to the ground that the impedance at resonance was too low and so they couldn’t get a decent SWR. They were shortening / lengthening. Nothing was working
Having the NanoVNA with a smith chart, it showed that the antenna was closer to 20 ohms at resonance. I got them to lengthen one end and shorten the other moving the feed point slightly off centre and increasing the feed point impedance without screwing up the resonance.
If you’re building a mag loop this is really important as resonance is key for efficiency. You want to find resonance first then match the feed to the loop