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Should I tune for Resistance or Impedence?

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Mar 27th 2023, 06:13
KT8DX Joined: Apr 4th 1998, 00:00 Total Topics: 0 Total Posts: 0	I have recently resurrected my old MFJ-204b antenna bridge/analyzer. It measures Resistance and resonance frequency. I also have a YouKits FB-01 that measures Impedance (z) and SWR. I typically have been using the FB-01 to test my portable and station antennas at the coax end by the transmitter, but I want to get more precise by adjusting the antenna at the feed point. Would it be better to use the MFJ and measure resonance and resistance or use the FB-01 to measure SWR and Z. I've read all kinds of stuff about this and frankly my head is swimming. Any thoughts or info would be greatly appreciated! Bob KT8DX
Mar 27th 2023, 07:32
W1VT Super Moderator Joined: Apr 4th 1998, 00:00 Total Topics: 0 Total Posts: 0	A Smith Chart is a graphical representation of impedance that is more intuitive than R +/- jX If you use a Smith Chart normalized to 50 ohms, the closer you get to the center the better the SWR.
Mar 28th 2023, 11:25
KT8DX Joined: Apr 4th 1998, 00:00 Total Topics: 0 Total Posts: 0	I'm planning on using this in the field for my POTA setups to gain more efficiency from my temporary antennas. Not sure carrying around a Smith chart is practical. Which of the two testers would give me more useful information? Thanks
Mar 28th 2023, 18:49
WA0CBW Joined: Apr 4th 1998, 00:00 Total Topics: 0 Total Posts: 0	In essence they are both telling you the same information about your antenna. You want a low SWR to make the radio happy. You want the antenna at resonance to make the antenna happy. Those don't necessarily occur at the same point. Your antenna may be resonant but not at the impedance of your radio/coax (50 ohms). Bill
Mar 31st 2023, 09:32
W1VT Super Moderator Joined: Apr 4th 1998, 00:00 Total Topics: 0 Total Posts: 0	If your head is swimming, it is likely that you aren't a math genius that can easily understand numbers well enough to tune by them. Many folks think in terms of pictures, so graphical representations are more understandable. You may want to investigate other analyzers to see if there is something with a display you understand. It may help to practice at home.